Sudden Overheating with New Water Pump

[Buck36952]

Ok, for the sake of full disclosure, I did a lot more than just the water pump.
Start: August 8 …….there are no issues and all is well with my TB (other than sounding like a B-52). Engine temp via dummy gauge is 210.
Now Enter August 9th – Ok, so my kids have a new basketball goal that requires antifreeze in the base. The penny-pinching side of me says to flush the systems to use new coolant in the cars and old coolant in the basketball goal. So, I use Prestone Super Cleaner on my 150K 2002 TB….LS w/ a crappy paint job. I run the prescribed 6hrs and decide to quiet things down w/ a new Fan Clutch. This is accompanied by a new Water pump. I add one more Super Cleaner for good measure and fire her up. Runs more quietly and idles at a perfect 210. However, first time on the road and temps begin to climb to approx. 220-230 (again, according to the dummy gauge). I replace the thermostat and the radiator cap. No such luck. I try burping the system, parking on an incline…etc. Nothing works. I recheck my water pump (NAPA premium line “Gates”) and hear a growl. I change that out and put in Prestone Extended Life (green). I do notice that the water pump impellers look almost charred whereas the old pump impellers look new…and was marked GM, so I assume it’s the original 2002 pump. Still have the same overheating issues. I can generally keep the temp down to 210 if I baby it and have the heat cranked. Lord have mercy, this thing has a heater. I took it in to a radiator shop and had a three way flush done since the mechanic found cool spots in the radiator. It now holds a uniform temp but still heats up the same. It appears the cooling system is generating a lot of pressure. Driving it a short distance makes the upper hose very firm…to the point that I’m uncomfortable standing by it …don’t want it to burst or anything. I tried a block tester (no change in fluid color), but you have to do that at idle and this thing will idle at 210 all day long. It only heats up when it's being driven. Sorry for being so long winded, but hopefully something in here will provide insight for a suggestion/diagnosis.

Thanks

 

[meerschm]

Welcome.

if you fill in the vehicle details, it helps.

you may want to get a way to read the temp from the OBD. only way to really see what is going on.

the radiator cap should limit pressure to 15 psi. that is what it is there for. you just changed it so it should be ok. can you see the overflow tank increase in level when it is hot, and decrease as it cools off?

do you have a check engine light on?

and the coolant you used is not the recommended one.

did you change the thermostat and water pump yourself?

( I wonder if you could have got one of the gaskets on funny which may interfere with the flow, or perhaps something got jammed in the thermostat from the radiator flushing activity which keeps it from opening properly.)

 

[triz]

FWIW I had a pump go bad right out the box.

 

[Mooseman]

The green coolant, although not the correct one, should not affect how well it works. Just the longevity of the coolant itself.

A bad water pump would still work unless the impeller completely falls off the shaft where it would just overheat all the time. Even if it had bad bearings or leaked, it would still work.

The two things that would really affect the temperature in this case are the fan clutch and thermostat. It is possible you got a bad thermostat although you had the same results with the old and new one . So this leaves the fan clutch that you changed because it was locked up. Maybe you got a dud? Once it's hot and running, can you stop the fan with your hand using a rag? If yes, then it's either a dud or there is something with the wiring to it. Swap the fan relay with another similar one. Another indication is if the temperature still goes up or down at highway speed. Just the air through the radiator from forward movement should be enough to keep it cool (like mine with efans). Oh and I used a Gates pump as well, no issues.

 

[gmcman]

Have you tried cleaning the coils of the radiator? Generally they stay fairly clean but it's something worth trying.....even though this seems to have happened after the repair.

I agree the stat could be faulty, did you also change the temp sensor as well with the stat? These are a good pair to change out at the same time.

 

[Buck36952]

Meerschm - Not exactly sure what else to say about the vehicle details. It's an 02 Trailblazer LS w/ 150K. I agree with your idea to check the temp out via OBD, but that will have to come when I get it in to a mechanic since I don't have anything like that on hand. There are no check engine lights on at present.
I did enjoy the opportunity of replacing my own stat and, yes, the gasket did remain in place......the second time.
Water pump and Fan Clutch... I replaced both myself. Twice on the water pump. But, I see no way possible to screw up a water pump.

Gmcman – It just seems awful coincidental that the temp sensor would register 210 every day since I’ve owned it and then suddenly start acting as though I’m overheating (only when driving). Is this typical of how bad temp sensors behave when they go out? In regards to the stat, the owner of the radiator shop stated that he had used his heat gun to confirm that the stat was opening at appropriate temp. One thing he did mention was that the engine SEEMED to air lock when he drove it. ...perhaps that would explain the charred appearance of the first water pump (well, the first one I changed).

Mooseman – Ignorant question of the day here, but… if the clutch IS good, how concerned do I need to be about my digits on the other side of that rag?
Ok, you mentioned temp going up at highway speed. If I go above 40mph or so (w/o heater on high), my temp will raise up on me. It doesn’t matter if it’s side road or highway driving. It definitely seems to be affected by the driver getting on the gas (like merging onto the highway).

 

[meerschm]

http://gmtnation.com/f25/overheating-after-repairs-see-details-inside-8001/index2.html

check out this thread.

 

[Mooseman]

I would ball up the rag and use it on the outer ring of the fan. Imagine an old drum brake. You should only need moderate friction to stop it if the clutch is bad. Basically it's just freewheeling.

As for the speed thing, more importantly, does the temperature drop at 60-70mph?

 

[Buck36952]

http://gmtnation.com/f25/overheating-after-repairs-see-details-inside-8001/index2.html

check out this thread.

Yeah, I ran across this thread the other day. The main difference that I notice is that his heats up at idle and cools at driving speeds. Mine is the opposite. If I could idle to work every day, I'd be golden.

There was a mention of a PCM update. How would I know if mine requires an update?
Another question: If there were exhaust escaping into the coolant system, why wouldn't the radiator cap allow pressure to bypass once pressure exceeded 15psi?

 

[Buck36952]

[SUP][/SUP]

I would ball up the rag and use it on the outer ring of the fan. Imagine an old drum brake. You should only need moderate friction to stop it if the clutch is bad. Basically it's just freewheeling.

As for the speed thing, more importantly, does the temperature drop at 60-70mph?

Moose - No, the temp doesn't regulate down. Only had one or two times that I got up to that range w/o the heater on full blast. Guess I'm a bit paranoid about heating to the point of damage. I can check it out again tonight to have one more opportunity to reference.

Ball up the rag and outer ring...check. Just now replacing the skin from the fan when I did the clutch. I can deal with losing a layer of myself on a car...just don't want to move on to leaving chunks of myself!

 

[gmcman]

Gmcman – It just seems awful coincidental that the temp sensor would register 210 every day since I’ve owned it and then suddenly start acting as though I’m overheating (only when driving). Is this typical of how bad temp sensors behave when they go out? In regards to the stat, the owner of the radiator shop stated that he had used his heat gun to confirm that the stat was opening at appropriate temp. One thing he did mention was that the engine SEEMED to air lock when he drove it. ...perhaps that would explain the charred appearance of the first water pump (well, the first one I changed).

Seems very coincidental and not likely. Reason I stated that is it's just good practice to change both when one goes out, since the PCM and gauge read from the sensor.

Has the engine been overheated? Your issues almost sound like a bad head gasket...leaking air bubbles into the water jackets will cause overheating issues. Overheating can warp the head causing this, has a coolant pressure test been performed?

 

[Buck36952]

Seems very coincidental and not likely. Reason I stated that is it's just good practice to change both when one goes out, since the PCM and gauge read from the sensor.

Has the engine been overheated? Your issues almost sound like a bad head gasket...leaking air bubbles into the water jackets will cause overheating issues. Overheating can warp the head causing this, has a coolant pressure test been performed?

Understood. The engine has definetely not overheated within the last 4-5 years (ie - duration of my ownership). The guy at the radiator shop said he thinks the radiator cleaners are resposible for gasket failures. Although, he would have a vested interest so I don't know that I can take that claim as anything more than supposition.

It really just doesn't make a lot of sense to me b/c it ran perfectly before the water pump/fan clutch replacement and then heated up the first time afterward.

 

[Buck36952]

I guess I should throw this question out there:

What is the coolant capacity for a 4.2 that has had the water pump replaced and radiator drained via the lower hose? Reason I'm asking is that I could only ever get 2gal into this thing. I realize that some will remain in the block, but I just want to make sure I don't have some massive air pocket trapped in there. If it requires more, are there any good methods for bleeding the system?

Just seems odd that a vehicle would take almost as much oil as antifreeze to run on!

 

[meerschm]

13.9 quarts

http://www.vadengmpp.com/owners-manual/chevrolet/2002-Chevrolet-TrailBlazer.pdf

I could not get two gallons(8 quarts) in after a drain from the bottom radiator hose.


the rad cap should relieve pressure, which would go to the overflow tank.

how does that look? again from the owners manual:

The vehicle must be on a level surface. When your
engine is cold, the coolant level should be at FULL
COLD, or a little higher. When your engine is warm,
the level should be at the base of the filler neck or a
little higher.


if there are gasses getting into the coolant, i would expect this not to be the case. (would overflow and/or suck down below full when the engine cools) if there is a bad leak in the engine/rad, no coolant would be sucked back in when it cools.

you may want to warm up from cold with the rad cap off. should see smooth flow, and some flow into the coolant recovery tank via the hose from expansion. if it is outgassing plenty, it will not cool properly. in operation, the coolant inside the radiator and engine is supposed to be all liquid, and under pressure.(up to 15 PSI) as it expands, some flows into the recovery tank.

 

[Buck36952]

meerschm - Just kind of pisses a guy off. I mean, it's not rocket science...it's a coolant system. I should be able to figure this one out. I see myself as above average for being mechanically inclined.

But yeah, I can put 8qts into a dry radiator if I've let it drain for about 30 minutes (well, I think that was also when I removed the water pump). I've got an appointment w/ a guy on Monday to see if he can figure it out w/ his diagnostic equip. He was telling me temp sensor all the way, until I told him it idles fine but heats up as you drive.

 

[chief0299]

Everything you have described leads me to believe you have blocked or partially blocked passages in the radiator. When you introduced the chemical into the coolant system to flush it, there is a good chance a chunk of, or a collection of, dirt or built up crud in the cooling system broke loose and collected in the passages of the radiator. The easiest way to confirm this is to buy a temperature gun and run it across the front of your radiator while the engine is running. However this may not be feasible due to the A/C condensor being in the way. Remove the radiator cap (when the engine is cooled down!!!) and start the motor. Look down in the hole as best you can and look for chunks of stuff floating around or obvious signs of built up crud.

At idle, the radiator is able to dissipate the moderate amount of heat the engine produces. Under load when there is more heat generated, the radiator can't dissipate the extra heat.

 

[Mooseman]

At this point, I'd have to agree with Chief, when the fan was locked and pulling tons of air, it could have compensated for a blocked radiator. The only thing left to replace is the radiator. Amazon has one for $77
Amazon.com: Sunbelt Radiators Inc. New Replacement Radiator OE Quality for BUICK RAINER: Automotive

Even though it says it's for a Buick Rainier, it interchanges with the TB with the same engine. Picture is also the same. Others are around $100.

When I was first running my efans, I found it ran a bit warm but nowhere as bad a yours. I put in a new radiator, helped bring it down.

 

[gmcman]

Chief's post sounds very plausible, I wouldn't have used the cleaning agent. Anytime I have flushed mine out I picked up about 8 gallons of distilled water from Walgreens and just used it to flush the system. Then refill with dexcool either premix or straight dexcool then mix with the distilled water.

Does the lower hose even get hot? Don't probe the stat housing since that could be misleading. Disconnect the temp sensor and see if the fan fully engages....should engage as a safety feature.

Which fan clutch and thermostat did you get?

Without going out and looking, can the fan be installed backwards?

Either the radiator is restricted as stated or the stat may possibly be faulty.

The fan clutch should spin slow and should be able to stop by a rag fairly easily when cold. Once warm you should be able to hear the air pulling through the radiator as it picks up speed. Generally there will be a code if the PCM commands a fan RPM and the corresponding RPM is not being seen by the PCM.

Definitely check to see if there is any debris in the radiator

 

[gmcman]

Any chance you can take a pic of the front of the motor showing all the pulleys, fan, belt etc? Let's make sure everything is rotating the correct way.

 

[Wooluf1952]

Not to be a smart ass here, but is it possible to install the serpentine belt so that the pump/fan runs backward?

 

[gmcman]

Not to be a smart ass here, but is it possible to install the serpentine belt so that the pump/fan runs backward?

Looking at the diagram for a few minutes... I think if you ran the belt from the PS pump, then over the top of the water pump pulley and under the idler above the AC compressor, then over the alternator.....it would run backwards. Not even sure if the belt would even fit that way but either case, the water pump will always turn opposite the crank (correct rotation) unless you route it this way......I think.

Would likely squeal like crazy when revved though on the water pump pulley with the minimal surface contact.

 

[Buck36952]

http://gmtnation.com/f25/overheating-after-repairs-see-details-inside-8001/index2.html

check out this thread.

I know there has to be a better way to do this, but I'm not familiar with the proper format. The above mentioned link has an image uploaded by Roadie on the first page. I have the Serp belt routed per that diagram.

I guess it's completely plausible that there is a radiator blockage. I kind of took the radiator guy's word that the flush had the radiator cooling evenly. He said he used his heat gun on it. Ended up running out of time yesterday, so I didn't get a chance to look at it at all last night. Will have to get to it tonight to check that fan clutch.

Thanks for all the input and keep those ideas firing. I do appreciate it!

 

[triz]

Just tossing this out there. Relay 45. Doesn't that have to do with the fan clutch?

 

[Buck36952]

Does the lower hose even get hot? Don't probe the stat housing since that could be misleading. Disconnect the temp sensor and see if the fan fully engages....should engage as a safety feature.

- Ran the TB last night for a bit to check things out. I didn't disconnect the Temp Sensor (will try tonight), but I did notice that the lower hose never did get warm. I was running with the rad cap off, so I don't know if that causes the stat to stay closed, but the lower hose remained spongey and cool...much cooler than the alt.

Which fan clutch and thermostat did you get?

- I picked up the clutch from NAPA. Not exactly sure who manufactures that. The stat is a Murray Plus that I picked up.

There had been mention of the fan clutch being suspect. I did test this out as Moose suggested. It did take a fair amount of pressure to stop, but it would come to a full stop.

 

[gmcman]

Upper hose should get a little warm during warmup, lower hose should be hot when temp needle is straight up or about 1 tick to the left of 210. Was the lower hose cool with the temp needle at thos positions?

Did you use RTV for the stat? Should only be an O-ring, no RTV needed.

I would recommend cutting your loss and change the stat to an AC or perhaps a Stant...I personally like to keep these items in the GM family, especially the temp sensor. Just that this would cover a base and it's not terribly expensive to do.

Double check the fan again but the fact the lower hose is cool, and if this is at normal oper temp, then I would definately check the coolant level and if good replace the stat.

 

[meerschm]

- Ran the TB last night for a bit to check things out. I didn't disconnect the Temp Sensor (will try tonight), but I did notice that the lower hose never did get warm. I was running with the rad cap off, so I don't know if that causes the stat to stay closed, but the lower hose remained spongey and cool...much cooler than the alt.

Pressure makes the hoses hard. with the cap off, both should be similar.

the upper hose will warm up after the engine gets warm enough to open the thermostat.

as the radiator fills with warm coolant, it will eventually enter the lower hose and back to the engine the lower hose should warm up after the radiator is full of warm water, minus the heat removed by the radiator.

The thermostat operates by temperature, not by pressure.



you may want to check the temp of the lower hose after a drive.

if it never gets warm, the rad could be mostly blocked. (since you said in a previous post about letting it drain for 20 minutes, i suspect this may be the case)

 

[Buck36952]

Upper hose should get a little warm during warmup, lower hose should be hot when temp needle is straight up or about 1 tick to the left of 210. Was the lower hose cool with the temp needle at thos positions?

Did you use RTV for the stat? Should only be an O-ring, no RTV needed.

I would recommend cutting your loss and change the stat to an AC or perhaps a Stant...I personally like to keep these items in the GM family, especially the temp sensor. Just that this would cover a base and it's not terribly expensive to do.

Double check the fan again but the fact the lower hose is cool, and if this is at normal oper temp, then I would definately check the coolant level and if good replace the stat.

Yeah, Temp needle is indicating an even 210 and the hose is completely cool. I did run a dab of RTV black on the o-ring to keep it in place. First install of new Stat resulted in the O-ring getting out of position. Leaked horribly and noticed that O-ring was cut in half when I removed. Reused old gasket with a film of RTV black to seat old gasket. Waited full 24 hours prior to filling radiator. All this happened after the initial overheating issue and before it went in to the radiator shop. Coolant level is spot on, but I do wonder if it a bad stat wouldn't result in a huge air pocket that can't be expelled. That, or it simply won't allow the cooler temped fluid to circulate. Geez! And those stats are such a PITA! More annoying than difficult, but still.

 

[Buck36952]

The thermostat operates by temperature, not by pressure.

Agreed. Just wondering if you have a working knowledge of how a stat can be checked accurately? Can it be done w/ a heat gun? How would you "see" that the stat is opening? May be ignorant....but then again, maybe I am!

you may want to check the temp of the lower hose after a drive.

if it never gets warm, the rad could be mostly blocked. (since you said in a previous post about letting it drain for 20 minutes, i suspect this may be the case)

Good idea. Need to get her on the road and really check that. Had baseball practice last night, so I wasn't able to accomplish much afterwards

 

[meerschm]

Agreed. Just wondering if you have a working knowledge of how a stat can be checked accurately? Can it be done w/ a heat gun? How would you "see" that the stat is opening? May be ignorant....but then again, maybe I am!



Good idea. Need to get her on the road and really check that. Had baseball practice last night, so I wasn't able to accomplish much afterwards

you could monitor with an IR thermometer, but the only way for sure would be to remove the thermostat and warm it on the stovetop in a pan of water and watch it open

there are some posts here where this was done, and some thermostats were seen to not open as far as others.

 

[Buck36952]

I did heat it on the stove, but the flaw in my process was that I had no clue at what temp it was opening. It did open though.

I need to look up the article about stats opening to varying degrees. Of course right now, I'd be happy to know for certain that mine if opening to ANY degree.

 

[meerschm]

http://gmtnation.com/f25/bad-thermostat-radiator-heats-up-along-engine-6355/index2.html

some light reading.

esp see post 37

(fyi, stovetop water should boil at 212f a bit less at altitude.)

 

[meerschm]

I did heat it on the stove, but the flaw in my process was that I had no clue at what temp it was opening. It did open though.

I need to look up the article about stats opening to varying degrees. Of course right now, I'd be happy to know for certain that mine if opening to ANY degree.

If the upper hose was warming up at idle, and you noticed some heat getting to the radiator, I am thinking it opened, at least some.

 

[gmcman]

The upper hose will get warm because it in contact with the coolant at the top of the block

 

[meerschm]

have to review the way this thing works.

coolant goes from the top of the block to the radiator, flows from top to bottom, then exits bottom. flow back to the block is controlled by the thermostat.

is this correct?

 

[meerschm]

http://www.justanswer.com/chevy/27p...lutch-fan-replaced-water-pump-thermostat.html

good discussion here of the various components.

except the discussion has wrong the detail as to where the thermostat is on the 4.2. it is between the radiator and the block, not the other way around.

 

[chief0299]

have to review the way this thing works.

coolant goes from the top of the block to the radiator, flows from top to bottom, then exits bottom. flow back to the block is controlled by the thermostat.

is this correct?

Correct. Hot fluid leaves the engine and goes to the radiator via the upper hose. This is why I believe you have a clogged radiator. Soft and cool lower hose, hot and stiff upper hose... pretty good indication of inadequate flow through the radiator.

 

[Buck36952]

Well, I dropped off the TB at the mechanic last night. He's going to look at it today and get back with me when he finds something out. I did take a minute to check the lower hose when I got to the shop. At idle, my lower hose was showing no sign of heat. Well, after driving about 10 miles at light to moderate pace (nothing above 65 and easy on the accelerator), I checked the lower hose and it was also firm and warm/hot.

I looked over the following thread



http://gmtnation.com/f25/bad-thermostat-radiator-heats-up-along-engine-6355/index2.html

and see a similarity between the pics of the stat. When placed in boiling water, my stat closely resembled the AC/Delco that was barely cracked open, as opposed to the Motorad that was wide open. However, replacing the stat was a step that was kind of in the middle of everything, ..once I'd already had a overheating issue.

I do appreciate all the suggestions from everyone. Chief, you had mentioned a blockage in the radiator. I definitely won't rule it out as a possibility, but I have mentioned previously that a professional shop had done a 3-way flush for me (following my own attempt with the Prestone Super Cleaner). Time will tell how thorough that flush was. It's always possible that your explanation is spot on and that the flush was not sufficient.

Bottom line is, the coach has benched me for the rest of this game and I'll be watching my replacement from the sidelines. Since it's her car, I can't put up too much a fuss....well, that and the fact that it's still not fixed Thankfully, it's not at a stealership and my new mechanic knows that he was referred by a whole line of family members/church members. Hopefully all turns out well. Will post updates as I get them. Perhaps it will give answers to someone else with issues down the road.

- - - Updated - - -

 

[chief0299]

Well, I dropped off the TB at the mechanic last night. He's going to look at it today and get back with me when he finds something out. I did take a minute to check the lower hose when I got to the shop. At idle, my lower hose was showing no sign of heat. Well, after driving about 10 miles at light to moderate pace (nothing above 65 and easy on the accelerator), I checked the lower hose and it was also firm and warm/hot.

I looked over the following thread



http://gmtnation.com/f25/bad-thermostat-radiator-heats-up-along-engine-6355/index2.html

and see a similarity between the pics of the stat. When placed in boiling water, my stat closely resembled the AC/Delco that was barely cracked open, as opposed to the Motorad that was wide open. However, replacing the stat was a step that was kind of in the middle of everything, ..once I'd already had a overheating issue.

I do appreciate all the suggestions from everyone. Chief, you had mentioned a blockage in the radiator. I definitely won't rule it out as a possibility, but I have mentioned previously that a professional shop had done a 3-way flush for me (following my own attempt with the Prestone Super Cleaner). Time will tell how thorough that flush was. It's always possible that your explanation is spot on and that the flush was not sufficient.

Bottom line is, the coach has benched me for the rest of this game and I'll be watching my replacement from the sidelines. Since it's her car, I can't put up too much a fuss....well, that and the fact that it's still not fixed Thankfully, it's not at a stealership and my new mechanic knows that he was referred by a whole line of family members/church members. Hopefully all turns out well. Will post updates as I get them. Perhaps it will give answers to someone else with issues down the road.

- - - Updated - - -

Let us know how it turns out.

 

[Buck36952]

Ok, got a call back from the mechanic. He's stumped. He said that GM specs are something like 225 +/- 5 degrees and that the TB is running up to 237. At this point the fan engages and cools it down to like 207. He said that the radiator is free of blockages but that the hoses do seem a little more pressurized than normal. However, no sign of exhaust in the coolant. In all, he can't find any issues. I know it's been mentioned on here already that there is a bulletin for a PCM flash for these new fan clutches. He mentioned it to me as well as his only other option.

So, it's about $110 for diagnostic at the stealers, but they drop the diagnostic once you have them fix it. Currently, I've got $15 in Rad cleaners, $250 in a fan clutch and water pump, about $30 for a new stat and rad cap, $35 in coolant and water, $65 for a flush, and $70 for the mechanic.

Running at about $465 and my ride still doesn't ride so good...

 

[chief0299]

Ok, got a call back from the mechanic. He's stumped. He said that GM specs are something like 225 +/- 5 degrees and that the TB is running up to 237. At this point the fan engages and cools it down to like 207. He said that the radiator is free of blockages but that the hoses do seem a little more pressurized than normal. However, no sign of exhaust in the coolant. In all, he can't find any issues. I know it's been mentioned on here already that there is a bulletin for a PCM flash for these new fan clutches. He mentioned it to me as well as his only other option.

So, it's about $110 for diagnostic at the stealers, but they drop the diagnostic once you have them fix it. Currently, I've got $15 in Rad cleaners, $250 in a fan clutch and water pump, about $30 for a new stat and rad cap, $35 in coolant and water, $65 for a flush, and $70 for the mechanic.

Running at about $465 and my ride still doesn't ride so good...

What part of Oklahoma are you in?