Poor ventilation/truck overheating?

[Beastmaster]

After a mere 1 month of ownership and 1200 miles on the wife's H3, I've noticed an interesting trend of the vehicle running continuously hot. Most of the time, the temps are sitting at 3/4, and when climbing hills, will run up to the red zone to where the A/C will shut off.

The clutch fan has been replaced, and the dealer is now throwing their hands up in the air. Has anyone noticed any bad thermostats coming out of the factory? Or does the H3 have really bad airflow to where I have to add a pusher fan to the outside radiator area?

TIA,
Steve

[PARAGON]

Originally Posted by Beastmaster

After a mere 1 month of ownership and 1200 miles on the wife's H3, I've noticed an interesting trend of the vehicle running continuously hot. Most of the time, the temps are sitting at 3/4, and when climbing hills, will run up to the red zone to where the A/C will shut off.

The clutch fan has been replaced, and the dealer is now throwing their hands up in the air. Has anyone noticed any bad thermostats coming out of the factory? Or does the H3 have really bad airflow to where I have to add a pusher fan to the outside radiator area?

TIA,
Steve

The T-stat shouldn't have anything to do with it running hot under the circumstances you described unless it's very restrictive. It doesn't sound like a "sticky T-stat" situation. Meaning, you could probably remove the T-stat completely and still experience your overheating, as described.

Auto or stick? Any aftermarket add-ons that could cause airflow restriction?

Doesn't the H3 have an oil cooler? Where is it and what does the oil look like now?

[Michael1]

Have you removed the radiator cap (WHEN COLD!), to be sure the coolant level is all the way to the top. Also, is your coolant reservoir full. After the system gets hot, be sure the coolant reservoir is topped off, so that when it cools, and draws in coolant, the reservoir doesn't become empty and just draw in air.

It could also be that you have a defective radiator with blocked tubes, or there was material left over from manufacturing that has blocked some of the tubes. After running the engine, turn it off (remove the keys so someone doesn't accidentely start it), place your hand in between the fan blades, and feel the radiator fins for uniform temperature. It should be very hot and uniformily hot, so be careful not to burn yourself. If there are cool bands, the tubes are blocked.

In cool weather, does the temperature stabilize? If so, then it also could be a thermostat that works, except not opening all the way. If you see wide changes on coolant temperature, near "C" when going down hill, and near "H" when going up, your thermostat may be stuck partially open.

I have noticed that the H3 does run hot in slow traffic on hot days. It never quite overheats, though, and the temperature comes down quickly when the engine speed comes up (increases fan speed).

Michael

[HummBebe]

It is regularly 90+ here in the summer. Never had this issue.

Sounds like a Q for f5fstop.

Call Hummer, they will keep the dealer so busy he can't "throw-up his hands"

It's probably going to be something simple. My guess, could be a relay?

[BABHUMV]

While towing about 4500lbs in traffic, I got he temp gage to go high, never to hot though. I am tending that the radiator is defective, you should not need to put on an extra fan.

[ketcat]

I live in Phoenix and mine runs in about the middle of the gauge most all of the time. The only exceptions are when it's over 100 and I'm moving slowly (4 wheeling) or stopped (idling in parking lot). At those times mine has gone all the way to the bottom of the H on the gauge and I'm pretty sure if I kept letting it idle it would have continued to get hotter. The last time it happened I was in a store and my wife and kids were sitting in it idling with the A/C on for about 20 min. It was 113 and she was sitting in a parking lot in direct sun. When I got in the needle was all the way to the bottom of the H. After driving for about 5 miles the needle was back to the middle of the gauge. About 30 minutes after I got back in the H3 we went through two drive thru?s which took about 10 to 12 min and by the time we got moving again the gauge was back almost as high as before.

Note: While the gauge on mine has gone very high it has never puked any coolant or overheated and the A/C has never stopped working. So unless your are in 110 PLUS temps for a couple of months at a time I would not be too worried about the gauge moving. If the A/C stop?s I would go straight to the dealer.


From what I understand it is a common problem in this area and Jay at Lund Hummer is working on a larger aluminum radiator for the H3.

As a side note he has completed a tune for the PCM and is getting some very good HP and TQ improvements from what I understand.
You can contact him at:
www.lundhummer.com

[Beastmaster]

Originally Posted by PARAGON

The T-stat shouldn't have anything to do with it running hot under the circumstances you described unless it's very restrictive. It doesn't sound like a "sticky T-stat" situation. Meaning, you could probably remove the T-stat completely and still experience your overheating, as described.

Auto or stick? Any aftermarket add-ons that could cause airflow restriction?

Doesn't the H3 have an oil cooler? Where is it and what does the oil look like now?

Oil's fine. I looked at that the first time it's happened.

It's an Auto. No aftermarket stuff yet since I'm waiting for more hardcore stuff to come out from RubberDuck (Travis), like better/beefier rock sliders and a full end to end UCP.

The first thing on the aftermarket bin will likely be a winch. But not until this gets resolved.