How much does your temp gauge vary in hot weather?

[bugeyed]

Until this hot weather & being stuck in traffic, my temp gauge was usually reading 210. I don't remember it ever moving above 210 before, but I may be mistaken. Now, in the heat (95+) & idling in traffic, the needle creeps up to 2 maybe 3 ticks above 210. I don't think it will go any higher than that, but haven't tested it. I changed the thermostat a year or two ago to get the reading up from a tick or so below 210. Should I be concerned &, if so, what do you think the problem is.

Thanks,
kev

 

[The_Roadie]

Yes, be concerned. How many miles do you have, and is there any other maintenance history?

The typical things are old or low coolant, cloggage in the radiator or crap in the fins between the radiator and the AC condenser, an about to fail water pump, bad fan clutch, bad hoses (although a collapsing hose usually happens at high RPM).

If you turn on the heater in the vehicle, does it act as a secondary radiator and help keep the gauge temp down? That's the typical emergency tactic to use, although passenger comfort suffers.

 

[bugeyed]

Yes, be concerned. How many miles do you have, 130k
and is there any other maintenance history? Fan clutch was changed years ago for the A/C at low RPM tech bulletin. No coolant flush, & not low. (Dex Cool)

The typical things are old or low coolant, cloggage in the radiator or crap in the fins between the radiator and the AC condenserI used a spray condenser coil cleaner on the condenser, but couldn't get to the radiator. I tried to get as much on the condenser coils hoping some would get through to the rad. then sprayed water through them.
, an about to fail water pump, bad fan clutch, bad hoses (although a collapsing hose usually happens at high RPM).

If you turn on the heater in the vehicle, does it act as a secondary radiator and help keep the gauge temp down? What would this tell me about the problem?
That's the typical emergency tactic to use, although passenger comfort suffers.

What do you suggest as a next step & then next & then after that?

Thanks,
kev

 

[tblazerdude]

Well coolant was due to be changed at 100k mi or 5 years. So do that. You are 30k overdue and 4 years late.

 

[The_Roadie]

What do you suggest as a next step & then next & then after that?

Depends on your budget and aversion to wasting money shotgunning and availability of friends with scan tools and if you need to drive it every day. Hard to predict what means the most to you.

Did you get the PCM update along with the new fan clutch, or did you not take it to a dealer and just change the fan clutch yourself?

I'd try to get it into the hot state with the coolant gauge over 210, then see if you can stop the fan with a rag on the edge. If the fan clutch is working well, it won't be possible to stop. If the clutch is marginal, it will be easy to stop.

But if you really have never changed or flushed the radiator, I'd start with that. Get a good cleaner, since low flow at low RPM can definitely be from clogged tubes. Or the water pump.

If the cabin heater helps cool the engine, it tells you the water pump is not the prime suspect.

 

[bugeyed]

Depends on your budget and aversion to wasting money shotgunning and availability of friends with scan tools and if you need to drive it every day. Hard to predict what means the most to you.

Did you get the PCM update along with the new fan clutch, or did you not take it to a dealer and just change the fan clutch yourself?

I'd try to get it into the hot state with the coolant gauge over 210, then see if you can stop the fan with a rag on the edge. If the fan clutch is working well, it won't be possible to stop. If the clutch is marginal, it will be easy to stop.

But if you really have never changed or flushed the radiator, I'd start with that. Get a good cleaner, since low flow at low RPM can definitely be from clogged tubes. Or the water pump.

If the cabin heater helps cool the engine, it tells you the water pump is not the prime suspect.

OK, going to change the coolant today. I have read the procedure for flushing the system & block & I don't want to remove the thermostat, as I replaced it a couple of years ago & it was a PITA! Anyway, can someone recommend the best procedure for getting an adequate coolant flush & replace without removing the thermostat?
BTW I did get the fan clutch replaced at the dealer with the PCM update & the A/C does work properly at idle etc. Also, As I mentioned I hadn't previously noticed the temp gauge going above 210 until recently. Does yours never go above 210? I had just changed the engine oil & cleaned the throttle body & had disconnected the battery. I did not do any reset procedure, so should I do something to reset the computer?

Thanks,
kev

 

[Sparky]

In really hot weather with the AC running and stuck in traffic my temp gauge has gone above 210 by a couple of ticks. I didn't see it as a cause for concern personally. It wasn't near the danger zone. Once traffic started moving again it dropped back, which makes me think the fan may not be able to move enough air to keep it quite as cool at the low engine speed.

 

[bugeyed]

In really hot weather with the AC running and stuck in traffic my temp gauge has gone above 210 by a couple of ticks. I didn't see it as a cause for concern personally. It wasn't near the danger zone. Once traffic started moving again it dropped back, which makes me think the fan may not be able to move enough air to keep it quite as cool at the low engine speed.

Well, I was only mildly concerned & so I inquired here. I stated exactly what you observed, 2 ticks above 210 & returning to 210 when moving & only after driving at highway speed & then stop & go traffic. It will sit idling in the driveway at 210 all day it would seem, at least it has for the last 30 min. The reason for my heightened concern is the first response I received was,
"Yes, be concerned. snip The typical things are old or low coolant, cloggage in the radiator or crap in the fins between the radiator and the AC condenser, an about to fail water pump, bad fan clutch, bad hoses (although a collapsing hose usually happens at high RPM)."

I do plan to replace the coolant today, as it's overdue. I let it go, because I replaced the thermostat 2 years ago, so I did replace some of the coolant then.
Thanks for your answer. Your's is the first response that answered the question in the subject line.

Thanks,
kev

 

[The_Roadie]

If I didn't explicitly answer the exact question, my apologies. At 100K miles, in 110 degree offroad desert conditions, using AC on full blast, at idle, my temp gauge stays at 210. Perhaps the difference is being at idle on black road surfaces so the IAT is 130-140 degrees? Can you get a scan tool on the vehicle to read the IAT, ECT, commanded fan RPM, and actual fan RPM?

 

[bugeyed]

If I didn't explicitly answer the exact question, my apologies. At 100K miles, in 110 degree offroad desert conditions, using AC on full blast, at idle, my temp gauge stays at 210. Perhaps the difference is being at idle on black road surfaces so the IAT is 130-140 degrees? Can you get a scan tool on the vehicle to read the IAT, ECT, commanded fan RPM, and actual fan RPM?

Not sure that my scan tool will do that. I think it only shows codes, sensors etc. I haven't done the grab the fan test yet, because I can't get it to run hot sitting in the driveway. Oh, BTW I can't find the manual & there are conflicting answers about the system capacity. What is it for the SWB 4.2l , 13.9 qt.? Thanks for all the attention to this.

Thanks,
kev

 

[The_Roadie]

Oh, BTW I can't find the manual & there are conflicting answers about the system capacity.

Google = Friend

http://www.vadengmpp.com/owners-manual/chevrolet/2004-Chevrolet-TrailBlazer.pdf

 

[Falcon LS]

It gets really hot here, up to 130 ambient, and my temp gauge stays at 100 C - I have metric instrumentation, I assume 210 is the equalivant. Having said that, I monitor coolant temperature on my ScanGauge-II and the highest I've seen it get to was 215 F. It's the ATF temperatures I'm more worried about, because it matches the coolant.

 

[CaptainXL]

Has the tranny fluid been flushed lately? I dropped 40 degrees going from Dexron 3 to Dexron 6. It usually runs at 175.

View attachment 29019

 

[Falcon LS]

Has the tranny fluid been flushed lately? I dropped 40 degrees going from Dexron 3 to Dexron 6. It usually runs at 175.

View attachment 15567

Absolutely, the pan is dropped at every oil change based off the OLM. I use Kendall Dexron-VI, one of the original formulators, and even did a line off flush.

Ambient temps are just too high here and the current cooler setup sucks. Getting a Derale pan with 2 additional quarts capacity and cooling tubes, as well as a proper cooler with a thermostat and fan.

 

[CaptainXL]

Its normal.

Found the following reply from GM in another forum about tranny temp.

I have consulted one of our dealers and am happy to inform you that I have the information you’ve requested.The normal operating temperature is between 160°F to 200°F (71°C to 93°C). For towing, the normal operating temperature is between 235°F (113°C) to 260°F (127°C).

You don't need to change the tranny fluid as often as the oil. I think your worrying about it too much. Every 30K is plenty.

Keep in mind I am in a cooler climate so compare 175 what I get to your highest temp of 215 in the hot desert and you notice its comparable.

Our cooler is more than enough. I would look into cleaning your radiator and checking your fan clutch.

In fact there was another gent on this forum (fadyasha) from the middle east and his radiator fins were full of dirt.

 

[Falcon LS]

Thanks very much for the input, Captain! Although that certainly makes me feel relief, I'm still looking to install that Derale transmission pan. An additional 2 quarts wouldn't hurt, and a drain plug will be a bonus. I'm looking to send a sample for analysis just to be in the safe, and see where that gets me.

I replaced the fan clutch with a GM part last month, and I blast my radiator with water on a weekly basis. Coolant (50/50 Dex-Cool to distilled water) is flushed out/replaced annually. One thing I'm looking into is replacing the radiator with something bigger, like the old Mopar one in one of the other threads.

 

[CaptainXL]

Thanks very much for the input, Captain!
Coolant (50/50 Dex-Cool to distilled water) is flushed out/replaced annually.

Umm. OK. You must like working on your truck a lot or spending money. Lol. Didn't you know that Dexcool is good for 5 years or 150,000 miles? Whichever comes first? Usually owners reach 5 years before 150,000 miles or 241,402 kilometers.

 

[Falcon LS]

To the best of my knowledge, GM recommends a 5 year/240,000 km coolant replacement interval on factory filled Dex-Cool. When you flush the system with a garden hose, there will always be impurities going in, even if you do mix distilled water in. Many manufacturers half the factory fill replacement interval for refills.

Having said that, living in a very dusty environment, dust/sand particles make their way into the coolant - despite it being a "sealed" system. It becomes apparent when you take the cap off the overflow tank and look at the bottom.

That said, it's only $22 for a gallon of ACDelco Dex-Cool here and that's all it takes to achieve a 50/50 ratio. :wootwoot:

 

[CaptainXL]

To the best of my knowledge, GM recommends a 5 year/240,000 km coolant replacement interval on factory filled Dex-Cool.

Yes, that's what I said.

When you flush the system with a garden hose, there will always be impurities going in, even if you do mix distilled water in. Many manufacturers half the factory fill replacement interval for refills.

There is no reason to flush out the system with a garden hose. Just remove the thermostat housing and lower radiator hose and drain. In order to do it right like this you risk damaging the thermostat. So that's why I am not recommending you do this so often. You did realize you need to remove the thermostat housing in order to properly drain the block?

Having said that, living in a very dusty environment, dust/sand particles make their way into the coolant - despite it being a "sealed" system. It becomes apparent when you take the cap off the overflow tank and look at the bottom.

You have sand in the coolant recovery tank? That doesn't sound right. Perhaps because you have never drained the block and are using tap water is the cause of the sediment (hard water). Flushing it the way you describe will only remove half of the coolant and leave a bunch of tap water in the system.

You just need to get it right one time and leave it alone. I realize you think changing it all the time is beneficial but in reality you could be doing more harm then good.

 

[Falcon LS]

My usual method is to remove the lower radiator hose and let it drain out. Then I take out the alternator, to remove the thermostat, and flush/back flush until it runs completely clear. Once it does, I always install a new OE thermostat, put the lower rad hose back in place, clean out the recovery tank thoroughly and refill with Dex-Cool/distilled water. I only use tap water to flush, not to dilute the coolant. There will always be some minor traces of tap water left in there though. Factory fill coolant is the purest the engine will ever see.

Very fine particles of sand in the coolant is actually quite normal in this part of the world, you even see it in the factory fill on brand new vehicles once it's been in service for a year. Quite a harsh environment for cars unfortunately - high sulfur gas, dusty weather conditions, temperature extremes in a lot of stop and go traffic, etc.

 

[CaptainXL]

Ok, my point is that you don't need to change the coolant every year. Nor the thermostat. If sand is getting into the radiator the only place it would be coming from is the recovery reservoir. For that all you need is a filter between the reservoir and the radiator. There is no benefit to replacing the coolant every year.

There, just save you a lot of time and money. Enjoy!