Overheating after repairs (See details inside)

[eXplicit]

So, I'm kind of at a loss at this point. I'm pretty sure I might know what the problem is, but I can't be sure. I'll summarize what's happened in the last couple months:

I bought a 2002 Trailblazer LTZ with about 140K on the clock. I bought it in Daytona Beach, and drove it home, about 60 miles. Just about 5 miles from home, the engine begins to overheat. It appears that the upper radiator hose was not secured properly and was losing pressure and fluid. I relieved the remainder of the pressure built up, fixed the clamp and hose, filled it up with water and drove it home. Ended up driving it to St. Pete at night about a week later, didn't have any problems until I was driving back around middle of the day. About 1/4 of the way home, about 35 miles, the motor started overheating. AC was running because it was probably in the mid 90s that day. Turned off the AC and drove it home and it stayed cool until I got off the interstate and came to a light. It then started to heat up until I started moving again. I checked a few things, figured the fan clutch needed replacement because it was free spinning pretty easy spinning after turning the motor off. Replaced the fan clutch, drove it to work which is about 30 miles in the morning with no problems. Drove home, same distance in the afternoon when it was really hot out, started overheating as I got off the interstate closer to home. At this point, I'm checking everything. Found what might have been a small hairline crack on the filler cap for the radiator. Had the radiator (and thermostat for safe measure) replaced. Drove it to work again in the morning today, everything was fine. Drove it home, got around the same spot (hot as all hell this afternoon again), and started to get hot. Not quite overheating, but I didn't sit at the light very long either. I got home and check, looked like the fluid might've been a little low, so I filled it up and let the air roll out. I'm pretty sure I got it all out, but it still bubbles a little. The reservoir is full, and doesn't look like it's taking any fluid, but it's boiling when I stop. Let it cool off a little, then run idle for a little while, couldn't get it to go over Normal Operating Temp.

One interesting thing I've seen is that from cold, the engine heats up QUICK! Even in idle. When I say quick, I mean it's usually at operating temp in about 5 minutes in idle. When I've let it cool off, I can start it back up and then let it sit idle with the AC running on high forever, and it won't go above Normal Operating Temp.

Now, here's where I think I might need to look next. I know that the engine is very sluggish, and from what I've been hearing, the catalytic converters on these clog up pretty easy. It seems that I need to replace it, but could this ultimately cause my overheating?


TL;DR: Replaced fan clutch, radiator, and thermostat. Bled lines. Still getting over normal operating temp when idle, but not while driving. Catalytic converter might be clogged, could that be it?

Any suggestions would be great. If I do need a new catalytic converter, what's a good price for one? Should I replace direct fit, or get it cut out and have a new one welded in? Etc?

 

[signalnc]

the engine should be at 210; and 5 minutes to get to 210 is normal. It doesn't take long.

are you sure it's overheating? or could it be a bad sensor. have you checked it with an ir thermometer

when you say it's overheating, what is the temp gauge saying?

 

[djthumper]

I don't know how I missed this posting... When you say hot how hot is it getting? Have you done a pressure check on the cooling system to see if it is holding pressure? It could just be the radiator cap is not holding the pressure.

 

[triz]

I would check the radiator cap pressure first. If that's well I'm going to have to say your water pump may be on its way out. If you need a water pump I have one in the FS section. Its from Napa 35 shipped. I also recommend this.

AMSOIL Dominator® Coolant Boost

Its helps with maintaining better operating temps and helps burp the system. Your heater should have been on all the way and the radiator cap off till you see no more bubbles.

 

[eXplicit]

Sorry, just getting back to checking this.

the engine should be at 210; and 5 minutes to get to 210 is normal. It doesn't take long.

are you sure it's overheating? or could it be a bad sensor. have you checked it with an ir thermometer

when you say it's overheating, what is the temp gauge saying?

Basically, it'll stay at 210 until I get to the light off the highway, or wherever I stop next. I can sit and watch it rise small intervals at a time. If I'm driving with the AC on, I'll notice that while I'm in the highway, it'll get a little over 210 (let's say 225 for lack of a better idea). But when I stop, it'll slowly increase, maybe a small notch every 30 seconds or so. I never really let it sit to see how hot it'll get because I don't want to cause any damage, but as soon as I start driving again, it will go back down (not all at once, but fairly quick).

I don't know how I missed this posting... When you say hot how hot is it getting? Have you done a pressure check on the cooling system to see if it is holding pressure? It could just be the radiator cap is not holding the pressure.

Like I said above, can't really say HOW hot it's getting because I'm not letting it sit long enough to get really hot, but I've seen it get to the 3/4 mark on the gauge while sitting at a stop light.

I called my uncle who's a general manager for Goodyear and he's going to have the block tested for me to see if I may need a new head. Haven't seen any of the obvious indicators of a bad cylinder head (i.e. Exhaust smoke, milky colored oil, oil in the coolant, etc.). The cap is the only thing I haven't replaced, but that's because it's already sort of new.

I would check the radiator cap pressure first. If that's well I'm going to have to say your water pump may be on its way out. If you need a water pump I have one in the FS section. Its from Napa 35 shipped. I also recommend this.

AMSOIL Dominator® Coolant Boost

Its helps with maintaining better operating temps and helps burp the system. Your heater should have been on all the way and the radiator cap off till you see no more bubbles.

I'll give that a shot today when I get home from work.

 

[eXplicit]

So, a little update. I came home to run the truck again, and noticed a wobbly sound, almost like a squeaky wheel in the engine compartment. I'm thinking at this point it's the water pump. But oddly enough, the fan doesn't flop around when off. I can't wobble it with my hand or anything. Does that make sense?

 

[Playsinsnow]

So, a little update. I came home to run the truck again, and noticed a wobbly sound, almost like a squeaky wheel in the engine compartment. I'm thinking at this point it's the water pump. But oddly enough, the fan doesn't flop around when off. I can't wobble it with my hand or anything. Does that make sense?

Loosen and remove drive belt. Rotate all the pulleys by hand. Any spin less freely than the others? Idler tensioner was a squeaker was for me...

 

[triz]

If you want to single out the tensioner have someone give it gas a few times while you check to see if it tightens the belt. (don't put your hands in of course) The tensioner should tighten up the belt when you give it gas.

Mine just went out. Got that at Advance Auto.

 

[eXplicit]

At this point I'm almost certain it's the water pump. Grabbing the center of the fan and moving it up and down gives a little bit of movement and you can hear the shaft moving around. I'm replacing it tonight and will drive it tomorrow to and from work and see if I get anything else with it. At this point, if it's not the water pump, I'm probably going to lose my mind.

 

[triz]

I have a water pump for sale 35 shipped and you would most likely get it by tomorrow if you haven't bought one by tonight. Just PM me.

 

[eXplicit]

I have a water pump for sale 35 shipped and you would most likely get it by tomorrow if you haven't bought one by tonight. Just PM me.

What brand? New or Re-manufactured?

 

[triz]

Its new. A Napa water pump. I had it as a replacement but the original pump gave out on me before I could install so I had to buy one on the road so its in a GMB box. Post office is closed so I can get it out in the am. You should get it next day.

 

[eXplicit]

Its new. A Napa water pump. I had it as a replacement but the original pump gave out on me before I could install so I had to buy one on the road so its in a GMB box. Post office is closed so I can get it out in the am. You should get it next day.

Just picked one up on the way home. Thanks anyway. Picked up a Bosch pump for $49.99 at Pep Boys.

 

[djthumper]

Good luck!

 

[tb boy 05]

the engine should be at 210; and 5 minutes to get to 210 is normal. It doesn't take long.

are you sure it's overheating? or could it be a bad sensor. have you checked it with an ir thermometer

when you say it's overheating, what is the temp gauge saying?

I'm glad I saw this post. I replaced my stat and water pump, and I thought I was having overheating issues also. I made an appointment to change my cat for next Friday because I thought that was the culprit. I drove the truck 14 hours continuous from Louisiana to Illinois on a bad stat and water pump, so I thought I did damage to the cat. Now i can use that money for my exhaust. Still might change the cat though, truck is stalling at traffic lights and while sitting at the light it seems to stumble at idle while waiting for the light to change. Any thoughts on this? didn't mean to thread jack just having similar problems.

 

[eXplicit]

I'm glad I saw this post. I replaced my stat and water pump, and I thought I was having overheating issues also. I made an appointment to change my cat for next Friday because I thought that was the culprit. I drove the truck 14 hours continuous from Louisiana to Illinois on a bad stat and water pump, so I thought I did damage to the cat. Now i can use that money for my exhaust. Still might change the cat though, truck is stalling at traffic lights and while sitting at the light it seems to stumble at idle while waiting for the light to change. Any thoughts on this? didn't mean to thread jack just having similar problems.

Mine doesn't exactly stall, or really have any idle problems, but it does hesitate when I rev it and really doesn't have a lot of power when I need to get on the Turnpike on my way home in the afternoons. I'll finish replacing the water pump tonight and see if that fixes the temperature issue. I know I'll need a new catalytic converter, so I may just hold the money and get a nice Flowmaster set up.

 

[triz]

I'm glad I saw this post. I replaced my stat and water pump, and I thought I was having overheating issues also. I made an appointment to change my cat for next Friday because I thought that was the culprit. I drove the truck 14 hours continuous from Louisiana to Illinois on a bad stat and water pump, so I thought I did damage to the cat. Now i can use that money for my exhaust. Still might change the cat though, truck is stalling at traffic lights and while sitting at the light it seems to stumble at idle while waiting for the light to change. Any thoughts on this? didn't mean to thread jack just having similar problems.

Yours is probably a clean your MAF(p) and throttle body issue. Also run a bottle of Amsoil PI Performance Improver or Techron through the system.

I wouldn't waste your time on the cat. A cat wont cause you to overheat and you would probably suffer more of a rev issue way before you overheated anything. The TB's have a history of idle/stumble annoyances. I would try the above first.

I'm not exactly sure from your post if you are overheating or were. Your temp should be right around the 210 mark. If you replaced the stat and water pump. I would check your radiator cap and make sure you burped the system properly as you might have some bubbles in the system. Amsoils Coolant Boost is what I'd recommend here if the system seems normal. It will help with burping the system and lower your operating temps.

 

[tb boy 05]

No I thought I was overheating because my temp was 210. I just found the thread on cleaning the throttle body, So I'm going to try that this weekend. I have to look for the how to on cleaning the MAF. Thanks for the info.

I have to look for the Amsoils coolant boost where I live. And I will check my cap when I get home.

 

[eXplicit]

Yeah, you'd be amazed at how much a clean throttle body can accomplish. I cleaned mine the week I bought it and it didn't really look like it needed it, but it could definitely use a cleaning. And the air filter looks like it had never been changed. Might as well check that while you're at it.

 

[triz]

Yeah 210 is right around where you should be. The MAF(P) is simple but Im pretty sure there is a how to here on it. Literally a 5 minute job. Pick up a can of CFRC Maf Cleaner, disconnect the MAF(P) spray it a few times plug and done.

 

[djthumper]

Clean the throttle body first, it will make a world of difference.

 

[eXplicit]

Just finished installing the new water pump. I'll get a better idea on my way home tomorrow if that fixed my problem. The old one doesn't seem to have any wobble or turn any slower or faster, but there's a sound coming from it when I turn the crank on it. Not sure if that'd affect the performance of it, but we'll just have to wait and see tomorrow.

If it doesn't fix it, I'm definitely heading to the shop for a block test.

 

[eXplicit]

Well, now I really don't know what to do. It started to get really hot again after I parked my car in the parking lot at my office. Basically, it was starting to creep up as soon as I got off the Turnpike, but didn't make it over 210 (it was sitting just below 210 when I was driving on the Turnpike). As soon as I came to the stop, it started to rise. I made it to the parking lot and sat for a few minutes as it started to rise. It made it just over 3/4 of the way up the gauge before I started to rev it, and when I started revving, it started to cool back down. I did notice that on my way to work, I started getting a fluid on my back window, almost as if something was leaking while I was on the road. When I stopped and checked at the office, I didn't see anything leaking under the truck, just the water dripping from the AC drain. I didn't have time to inspect it under the hood, but I will when I get home this afternoon.

Any ideas?

 

[The_Roadie]

I know you said in post #1 that you changed the fan clutch. Have you tried to stop it from turning with a rag when you're stopped and the temp has risen? If airflow when moving is enough to keep the temp down, about all the difference can be when you're stopped is insufficient fan airflow caused by a bad clutch or debris in the radiator fins or low coolant flow due to a bad water pump or clogged coolant passages in the engine or the radiator.

I'd be thinking about a radiator interior cleaning, or at the very least measure the temp on various parts of the radiator by hand or a non-contact infrared thermometer.

Your hoses OK and not collapsing? That's generally a problem with higher RPMs, not idle, though.

 

[eXplicit]

I know you said in post #1 that you changed the fan clutch. Have you tried to stop it from turning with a rag when you're stopped and the temp has risen? If airflow when moving is enough to keep the temp down, about all the difference can be when you're stopped is insufficient fan airflow caused by a bad clutch or debris in the radiator fins or low coolant flow due to a bad water pump or clogged coolant passages in the engine or the radiator.

I'd be thinking about a radiator interior cleaning, or at the very least measure the temp on various parts of the radiator by hand or a non-contact infrared thermometer.

Your hoses OK and not collapsing? That's generally a problem with higher RPMs, not idle, though.

Well, I've replaced the radiator, thermostat, fan clutch, and just last night the water pump. I can drive it around town fine. I drove it last night for a good 30 minutes or so, even sat in a Steak N Shake drive thru for about 20 minutes, and it didn't get hot. It stayed below 210. The only time it happens that I've seen is when it's been driven on the highway for 20 minutes or so during the day, and as soon as I come off the highway it starts raising. I let it idle for a while last night and checked the temperature of the radiator fins with an infrared thermo and it read under 100 degrees (like 95).

 

[CaptainXL]

Sounds like a clogged radiator.

 

[eXplicit]

Sounds like a clogged radiator.

2 different radiators have done this. The one that's in it now has been in there less than 2 weeks.

 

[CaptainXL]

OK. So if it starts to cool down when you rev the engine its either one of two things.

A. The fan clutch isn't working right or wiring or pcm is bad.
B. There is a restriction in the cooling system somewhere.

What temps are you seeing when coming off the highway? What does it get up to?

 

[eXplicit]

OK. So if it starts to cool down when you rev the engine its either one of two things.

A. The fan clutch isn't working right or wiring or pcm is bad.
B. There is a restriction in the cooling system somewhere.

What temps are you seeing when coming off the highway? What does it get up to?

I'm going to rule out the restriction. I've been through the entire thing thoroughly and haven't seen a lack of flow in it. It's definitely circulating. As for the wiring, how would I test to see if the fan clutch is working right?

 

[CaptainXL]

I'm going to rule out the restriction. I've been through the entire thing thoroughly and haven't seen a lack of flow in it. It's definitely circulating. As for the wiring, how would I test to see if the fan clutch is working right?

What temps are you seeing when coming off the highway? What does it get up to?

An exhaust restriction can also cause an engine to begin to overheat by not allowing the cylinders to cool down. I suggest getting your exhaust pressure checked before proceeding any further.

 

[eXplicit]

What temps are you seeing when coming off the highway? What does it get up to?

An exhaust restriction can also cause an engine to begin to overheat by not allowing the cylinders to cool down. I suggest getting your exhaust pressure checked before proceeding any further.

They'll creep slowly past 210. I sat in the parking lot this morning when I got to work and waited for about 5 minutes and watched it go from 210 to whatever the 3/4 mark is on the gauge. I revved it and it cooled down pretty quick, almost down to 210. It didn't go straight down, but it gradually came down over like 10 seconds. Then I just shut it off.

 

[CaptainXL]

You need to get a scan tool to read coolant temps. Never go by just the analog gauge.

It really sounds like an exhaust restriction to me.

 

[eXplicit]

You need to get a scan tool to read coolant temps. Never go by just the analog gauge.

If I go to Advance Auto Parts, they can do that for me there, right?

 

[CaptainXL]

If I go to Advance Auto Parts, they can do that for me there, right?

They should. But considering all the money you have spent on shotgunning parts I was sure you would have sneaked a scan tool in there.

 

[eXplicit]

They should. But considering all the money you have spent on shotgunning parts I was sure you would have sneaked a scan tool in there.

Well, I can get access to one. I've been holding off on buying one of those bluetooth OBD2 plugs. Should just get me one of those.

 

[CaptainXL]

If you have an Android device and you work on vehicles then there is really no reason to not get a Bluetooth adapter and Torque Pro.

This would be like step 1 in diagnosing your vehicle. Check engine codes, coolant temps, etc...

Just make sure to get the exhaust back pressure checked next. You did state that the converter probably needs to be replaced.

 

[eXplicit]

If you have an Android device and you work on vehicles then there is really no reason to not get a Bluetooth adapter and Torque Pro.

This would be like step 1 in diagnosing your vehicle. Check engine codes, coolant temps, etc...

Just make sure to get the exhaust back pressure checked next. You did state that the converter probably needs to be replaced.

Yeah, but I haven't really gotten a clear answer as to that being the problem. Some say it would do it, other say it wouldn't.

 

[CaptainXL]

Yeah, but I haven't really gotten a clear answer as to that being the problem. Some say it would do it, other say it wouldn't.

You aren't making any sense and you seem a tad emotionally compromised. Understood. I think you might be better off having a shop look into it for you.

 

[eXplicit]

You aren't making any sense and you seem a tad emotionally compromised. Understood. I think you might be better off having a shop look into it for you.

Which will probably occur next week.

 

[eXplicit]

Well, I scheduled a time to go up to the shop tomorrow. We'll see what the test results are.