Weird overheating issue

[Steveinfl]

Hi Everyone,

Hadn't been on here in a while but Delila has had a fit and seems to be running a temperature, time to get her feeling better soon.

I had my A/C serviced and a leaky waterpump replaced at the same time. I have a suspicion that the mechanics sabotaged it somehow but I can't prove anything, its always possible something just broke. They didn't seem to be a fan of me for whatever reason.

My first long drive after getting it out of the shop from Orlando to Savannah it overheated the whole way, wavering between 215 and 220 according to the scan gauge. This was barely maintaining 70 on I-95 as well. I drove it home carefully and without the mattress and box spring on the car slowing it down I made it home at a better speed but still running upward of 212 the whole time. Heat isn't as effective as it used to be either, going to try and disconnect the hoses to the heater core and separately flush it one of these days. The Coolant temp sensor was replaced ~3.5 years ago along with radiator, water pump and t-stat.

Got the car home and:

1. flushed the radiator to all water, ran it for a day or so and re flushed it. I did this several times.
2. Replaced the thermostat and refilled with 50/50 dexcool and distilled.

Nothing changed, maybe a slight improvement. No funk came out of the radiator either. It was essentially clean from a visual perspective at least.

3. Replaced radiator
4. replaced water pump (again)
5. replaced fan clutch
6. replaced radiator cap

put it all back together with proper coolant and it is only slightly improved. Took it on the highway this afternoon and saw temps of 215 when I goosed it to get onto the highway. It settles down to 206-210 afterwards as long as I'm not passing or running it hard.

There is no frothy mess on my dipstick or film floating in the coolant to show a head gasket leak. I haven't lost any noticeable coolant either. I more than adequately burped the system when refilling and it does not bubble when I take the cap off and watch it. There is a flow of coolant noticeable as well so the thermostat is at least partially opening. Around town the car runs just fine, barely passing 203 on the scangauge. It is only at sustained 50mph+ that it slowly creeps up and only stops when I let off the gas. Trying not to waste too much more $
on getting it sorted.

transmission temp is inline with where it usually sits (<185) and I bet the extra trans cooler is helping things the way they are right now. This happens after a half hour or so of highway driving or when the car is fully up to temperature. The temperature reading is pretty consistent so I would be surprised if that is the culprit.

I have an old thermostat body which I removed the thermostat from. I just installed it today. Will see how it does tomorrow when its 100 degrees out.

Any thoughts?

I accidentally posted this on the "other" site first out of old habits. it amused me at least. Maybe you all as well.
Thanks,
Steve

 

[Blckshdw]

Sorry to hear about your luck Steve. Buddy of mine on this end of I4 is having the same situation with his XUV. We've replaced all the same components except for the radiator, which is next on the list.

I was just talking to him earlier today about trying to gut his old thermostat and using it the same way you did. His temps have been running a bit higher than yours and don't come down unless he turns the heater on. His transmission temps run higher as well, although he only has the stock tranny cooler.

 

[Mooseman]

Probably because the coolant doesn't have enough time to cool down through the radiator. Even a stuck open t-stat restricts the flow enough to cool it.

I have a feeling it's your t-stat that's causing the issues although I don't consider those temps as "overheated" unless it keeps creeping up heading towards halfway to the overheated end of the gauge. Mine sits at just under 212 with A/C off and just above with it on and hot out, although I haven't confirmed the accuracy of the gauge yet with either my Tech 2 or Torque.

 

[Steveinfl]

Took the truck out for a drive on the highway tonight. Around 85 degrees out and A/C on max. Drove around 50 miles I'd say and the temperature maxed momentarily at 195 and held steady at 179-186 the rest of the way at 75mph.

This was essentially with no thermostat, meant as a test only.

I had almost forgotten how much of a bugger that bottom thermostat bolt was to get to, not that the alternator bottom bolt is much easier.

 

[Steveinfl]

I know its not full blown over heating and I'm being overly careful. I don't think 220 is going to hurt the engine at all. Its just warmer than it used to be and the scangauge lets me keep way too close an eye on it. It'd be nice to know I can make a high speed highway run again without running too hot as well. This running with the pack at 75 ish doesn't always work.

 

[gmcman]

215 deg is I believe within the normal temps for the I6....on the high side but not out the question. Hopefully someone will post the service spec for the normal range.

 

[Matt]

I honestly don't think there's an issue. I just replaced my thermostat and water pump. Prior to that I was seeing up to 218°.

Now it runs between 203.8° and 210.2°. If I jump on it to get onto the highway, I see it go to maybe 212° and then settle down, this at 70mph.

So, seeing as though your air temp is somewhat higher than mine and you're running faster than me, I'd say your OK.

 

[coolasice]

Normal range is 204-217 with anything over 257 turning on the temp warning indicator...

 

[Steveinfl]

I'll get another thermostat ordered and see what happens. Hopefully it stays in that 201 to 207 range for the most part.

 

[Steveinfl]

It's better than it had been. I haven't seen it over 210 but it still behaves weirdly with the A/c on. I am going to have that looked at eventually. Thanks for the suggestions.

 

[jsheahawk]

Maybe a gunked up radiator? Have you tried running up to temp and hosing down the radiator with water?