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View Full Version : High Temp (Suburban) ... thermostat?


PendO
11-05-2007, 02:11 AM
So, the suburban seems to be idling at high temps and operating at high temps when driving in town, but goes down to 210 when I'm at 60 on the hwy ... thermostat?

07 6.0L

PendO
11-05-2007, 02:12 AM
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PendO
11-05-2007, 02:13 AM
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Chicago190
11-05-2007, 02:18 AM
Are the fans operating properly? I'd check the fans, burp the cooling system, and then drain and refill the coolant before replacing the thermostat. Although since its cheap and easy you may want to replace it while you have the system drained anyway.

PendO
11-05-2007, 02:27 AM
the auxillary fan (loud one) is on almost all the time

how would I burp the cooling system?

I have a 7:45 appointmet at the dealership so I hope they can trouble shoot it out since it is still under warranty ... allegedly 230 is within acceptable limits?? ... they seemed skeptical that they could do a warranty claim for the thermostat unless it was overheating (I hope I don't have to take it to 260 for a warranty claim) ... so I said I would pay to have a new t-stat put in and see if that fixes it (and if so they can warranty out the part - otherwise I don't mind starting there on my dime) ... then over the weekend I took these pictures so I hope that can help the tech troubleshoot (and the problemseems to be getting progressively worse)

Ric
11-05-2007, 08:18 AM
I think your problem is all that dust and guuk built up on the instrument panel

bcampbe7
11-05-2007, 08:22 AM
Holy smokes Pendo... You already have 20+K miles on that thing!

I did just get a notice from GM about faulty instrument panels. I think it is just for the 04-06 models though.

BrianM
11-05-2007, 09:19 AM
Holy smokes Pendo... You already have 20+K miles on that thing!


That sounds about right to me. My '07 Avy has right at 28k on it.

With 20k+ miles Pendo is now at about $1 a mile in body repairs :rolleyes:

88 PS190
11-05-2007, 10:06 AM
Most of the time faulty thermostats cause the auto to run cold from what I've experienced, as they often fail in the open posistion.

But that doesn't mean they couldn't fail closed.

Chicago190
11-05-2007, 05:55 PM
the auxillary fan (loud one) is on almost all the time

how would I burp the cooling system?

I have a 7:45 appointmet at the dealership so I hope they can trouble shoot it out since it is still under warranty ... allegedly 230 is within acceptable limits?? ... they seemed skeptical that they could do a warranty claim for the thermostat unless it was overheating (I hope I don't have to take it to 260 for a warranty claim) ... so I said I would pay to have a new t-stat put in and see if that fixes it (and if so they can warranty out the part - otherwise I don't mind starting there on my dime) ... then over the weekend I took these pictures so I hope that can help the tech troubleshoot (and the problemseems to be getting progressively worse)

Burping is only usually necessary right after changing the coolant because air pockets get trapped and cause the engine to run hot. The procedure is listed here: http://www.ehow.com/how_7369_burp-cars-cooling.html Hopefully the dealer takes care of everything for you.

TX.X-30 fan
11-05-2007, 07:16 PM
What degree thermostat is on the vehicle? 225 sounds hot to me, I would let that cool some before I burped it. :D

I have a 165 on my wife's suburban, that may not work in the colder area's though. We have serious global warming down here. :rolleyes:

I can't see why they would want the coolant to run that hot, but I didnt stay in Holiday Inn Express last night so what do I know?? :D

Ski-me
11-05-2007, 07:59 PM
I would think that it would have a 195 thermostat in it. All the suburbans and K5 Blazers I've had started with a 195. With a reading like that, I would bet it's an instrument/electrical issue rather than the actual temperature of the engine. If it was running that hot, you would surely be getting a check engine light and the truck would probably be running in "limp" mode.

Let us know what they find. I assume it's still under factory warranty.

dog paw
11-05-2007, 08:17 PM
If it's full of coolant I'd be getting those fans checked out. The Stat is down at the water pump on that one. If the "high" fan is the only one running something is wrong...

Here's a breif description of operation..


The engine cooling fan system consists of 2 electrical cooling fans and 3 fan relays. The relays are arranged in a series/parallel configuration that allows the engine control module (ECM) to operate both fans together at low or high speeds. The cooling fans receive positive voltage from the cooling fan relays which receive battery positive voltage from the underhood fuse block. The fan relay coils receive ignition 1 voltage from the powertrain relay.

During low speed operation, the ECM supplies the ground path for the low speed fan relay through the low speed cooling fan relay control circuit. This energizes the low speed fan relay coil, closes the relay contacts, and supplies battery positive voltage from the low fan fuse through the cooling fan motor supply voltage circuit to the left cooling fan. The ground path for the left cooling fan is through the cooling fan series/parallel relay and the right cooling fan. The result is a series circuit with both fans running at low speed.

During high speed operation the ECM supplies the ground path for the low speed fan relay through the low speed cooling fan relay control circuit. The ECM grounds the high speed fan relay and the cooling fan series/parallel relay through the high speed cooling fan relay control circuit. This energizes the cooling fan control relay coil, closes the relay contacts, and provides a ground path for the left cooling fan. At the same time the high speed fan relay coil is energized closing the relay contacts and provides battery positive voltage from the high fan fuse on the cooling fan motor supply voltage circuit to the right cooling fan. During high speed fan operation, both engine cooling fans have their own ground path. The result is a parallel circuit with both fans running at high speed.

SunCoast 83
11-05-2007, 08:24 PM
Maybe a sensor in the computer?....my Explorer has had a false oveheat before due to a sensor.

Jerseydave
11-05-2007, 08:38 PM
How's the temp with the A/C on? This should make the fan(s) come on and stay on.

I would demand the dealer fix under waranty. I would think 210-220 would be the normal temp at the most.

TX.X-30 fan
11-05-2007, 09:00 PM
Maybe a sensor in the computer?....my Explorer has had a false oveheat before due to a sensor.



Before or after it burned to the ground? :D

PendO
11-05-2007, 09:13 PM
turns out it was a fautly temp. sensor ... should be fixed tomorrow with the part being overnighted ... dship even offered me a loaner ... thanks fellas

service writer was way nicer today ... no more telling me it was w/in specs ... maybee the pics helped:)

Workin' 4 Toys
11-05-2007, 09:42 PM
For the amount of times you smashed that thing already, it could be a few problems. My first guess is air in the system. Guess #2 issues with the sensor, possibly even a pinched wire. You never know what might come of it after what that poor truck has gone through.
Guess #3- Ric is probably right..8p

dog paw
11-06-2007, 08:23 AM
For the amount of times you smashed that thing already, it could be a few problems. My first guess is air in the system. Guess #2 issues with the sensor, possibly even a pinched wire. You never know what might come of it after what that poor truck has gone through.
Guess #3- Ric is probably right..8p


Is this the same vehicle that was posted a while back crushed to hell and back that everyone walked from? I think at the time it was brand new.

A little bit of dust never hurt nothing my dash is covered with doberman fur :D