Engine temp gauge moves up a couple of lines only

Ariel Guerra

Original poster
Member
Jul 11, 2012
17
Over the past month after driving on the highway as soon as I come to a stop the temp gauge goes from the 210 mark it had ben at the whole time up 2-3 lines above that. It never goes above that and stays there. The gauge will go down a line or so once I start driving again, and back down to 210 if drving on the freeway again.

So what gives? Is temp of 212/218 my truck's new norm? Obviously it doesn't get near to over heating but still isn't "normal" like before.

I replaced the water pump a couple of weeks after the gauge started doing this, but that was because it was causing the wobbling rattle.


Could it be a thermostat problem? Is the fan clutch be going? It does spin/work, but could it be not working correctly or beginning to fail?

Any ideas?

My vehicle is an '02 Envoy 190,000 miles
 

christo829

Member
Dec 7, 2011
508
Fairfax, Virginia
Mine has started to do the same thing on the days where the ambient temperature sensor
reads about 96 or higher. My guess is that I either have something obstructing some of the cooling
fins on the radiator, some plugged tubes in the radiator, or the fan clutch isn't doing the job.

Unfortunately, I haven't had time to dig in and assess the problem, haven't been driving
for long periods of time, and really been trying to avoid driving when the temps are that
high. Those are days when I'm really glad I don't do field work any more... :wink:

If I figure out why mine is acting up, I'll post back in, but those three items are where I'd start.

Good Luck!

Chris
 

Ariel Guerra

Original poster
Member
Jul 11, 2012
17
christo829 said:
Mine has started to do the same thing on the days where the ambient temperature sensor
reads about 96 or higher. My guess is that I either have something obstructing some of the cooling
fins on the radiator, some plugged tubes in the radiator, or the fan clutch isn't doing the job.

Unfortunately, I haven't had time to dig in and assess the problem, haven't been driving
for long periods of time, and really been trying to avoid driving when the temps are that
high. Those are days when I'm really glad I don't do field work any more... :wink:

If I figure out why mine is acting up, I'll post back in, but those three items are where I'd start.

Good Luck!

Chris

I'll check the radiator when I wash the truck today, and if you find out what it is it'd be great to hear from you.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
An '02 that's never had the fan clutch replaced with the '05 redesigned version is a ticking time bomb. Yours might have failed. It will always spin due to residual friction in the clutch assembly, but if you can easily stop it with a rag, it's not engaging properly if your temp is anywhere above 210.

Only a Tech II tool or equivalent that ran read commanded fan RPM versus actual fan RPM is going to be a firm diagnosis, and that might cost you 1/2 of the cost of a new clutch. I'd also double-check the harness and connector going to the clutch, but if that has an open connection, it should light up the SES lamp with a code.
 

Ariel Guerra

Original poster
Member
Jul 11, 2012
17
the roadie said:
An '02 that's never had the fan clutch replaced with the '05 redesigned version is a ticking time bomb. Yours might have failed. It will always spin due to residual friction in the clutch assembly, but if you can easily stop it with a rag, it's not engaging properly if your temp is anywhere above 210.

Only a Tech II tool or equivalent that ran read commanded fan RPM versus actual fan RPM is going to be a firm diagnosis, and that might cost you 1/2 of the cost of a new clutch. I'd also double-check the harness and connector going to the clutch, but if that has an open connection, it should light up the SES lamp with a code.


I checked my records and I found that I replaced the clutch almost 4 years ago exactly. Of course it was also about 60k miles ago, if mileage makes a difference with these things.

Do you know if having the redsigned version make a difference with my situation Roadie?


Also, since I just replaced the original alternator two days ago, I'm a bit strapped for cash. About how much time do you think the clutch may last? I'm hoping five weeks till the 1st of September if possible.
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
It's not like the fan clutch is guaranteed bad, just that it needs a proper diagnosis. It's also not going to be horrible if it fails totally, as long as you watch the gauge and if you're in slow traffic and it gets too hot, turn off the AC, turn on the heater, roll down the windows, put the HVAC blower on high and use the heater core an an auxiliary radiator.

And as Chris posted, it may not be the fan clutch at all.
 

Ariel Guerra

Original poster
Member
Jul 11, 2012
17
the roadie said:
It's not like the fan clutch is guaranteed bad, just that it needs a proper diagnosis. It's also not going to be horrible if it fails totally, as long as you watch the gauge and if you're in slow traffic and it gets too hot, turn off the AC, turn on the heater, roll down the windows, put the HVAC blower on high and use the heater core an an auxiliary radiator.

And as Chris posted, it may not be the fan clutch at all.

Cool, then I'll keep an eagle eye on it and get it checked as soon as I can.

Thanks guys.
 

Wooluf1952

Member
Nov 20, 2011
2,663
Milwaukee, Wisconsin
Ariel Guerra said:
Over the past month after driving on the highway as soon as I come to a stop the temp gauge goes from the 210 mark it had ben at the whole time up 2-3 lines above that. It never goes above that and stays there. The gauge will go down a line or so once I start driving again, and back down to 210 if drving on the freeway again.

So what gives? Is temp of 212/218 my truck's new norm? Obviously it doesn't get near to over heating but still isn't "normal" like before.

I had the almost the same problem on me Envoy, except mine ran at 217* and climbed to about 225* when coming to a stop.
As I would start driving again, the fan made the jet engine sound, so the fan clutch was working right.
I changed the t-stat and temp sensor and it now runs at a solid 210*.
Yesterday I saw, for the first time ever, the outside temp reading of 100* and even with the AC on, the engine temp was solid at 210*.
 

gunrock

Member
Mar 27, 2012
22
Wooluf1952 said:
I had the almost the same problem on me Envoy, except mine ran at 217* and climbed to about 225* when coming to a stop.
As I would start driving again, the fan made the jet engine sound, so the fan clutch was working right.
I changed the t-stat and temp sensor and it now runs at a solid 210*.
Yesterday I saw, for the first time ever, the outside temp reading of 100* and even with the AC on, the engine temp was solid at 210*.

Yeah I have the same thing...runs a tick below 210 (which is around 199-201? on my odbcii reader, IIRC) most of the time, until it get's 90 degrees F plus out, then it creeps to 210 on the truck guage, then sometimes two notches above that which is about 220 on the reader. Once it went higher, 230, then the fan kicked in high.

I can idle all day and it won't get hot. Only when it's 90 plus out driving or 85 plus and towing. Temps will come down either hitting the highway or by kicking in the heat for a few (or sometimes just idling). I had a few times where highway speeds alone wouldn't bring down the temp, then kicked in the heater, all was fine.

Assuming all else is fine (no rad blockage or leaks, coolant sensor good), could this be a symptom of a bad thermostat? Could it be lazy and open quick enough to get up to temp, but not enough to allow for the hotter ambient temps? I only ask because I read an article from an engineer from Stant on how they work and this is my interpretation of it.
 

CaptainXL

Member
Dec 4, 2011
2,445
Assuming the water pump is working well I would be checking for over-concentrated coolant, fluid level, radiator cap pressure and fins for damage or obstruction. Fins can easily be damaged when replacing the fan clutch so make sure the shop didn't do that.
 

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