H3 3.7 Auto Overheating

Hi Guys

Huge problem, I had no problems with my H3, towing ext. before. In the last three weeks I have been doing some towing. First my camping trailer, no problems. Doing the same route with my boat, going there, no problem, comming back on the same route the rig starts to overheat.
:gaah:
Normally the temp ran below the middle mark and then it leveled out just above the middle mark. Then it just kept going up to the 3/4 mark when the "oil" warning lights started to flash. I pulled over and it stopped. As I am starting to get closer to home, the temp starts going down but never lower that the middle mark.

So, got the radiator tested for gas and pressure. No problem. The radiator not blocked at all.
:huh:
Took the fam on a camping trip last weekend, drove a short distance with the trailer and it started to heat up again. The rig is Auto so I switch from Drive to 3rd, keep the refs up, doing between 60 and 80 km/h. The temp falls, still above middle mark, and stays there. The moment I slow down or increase the speed, it overheats again.

I know this is alot of info but if anyone could give me any advise I would really appreciate it. I want to take the truck to the dealers but they are a couple of ours drive away. Before I do that, maby it could be something small.

Thanks in advance....

3/4 on the temp gauge is still within the normal range. When the truck overheats I don't think you get oil warnings but instead it shuts down the a/c and (maybe) goes into a reduced power mode.

If you are getting oil messages then I would look at oil levels, oil quality, time since last change, etc.

I'm sure others will have some other ideas as well

X2 on what Alrock said. Oil warning lights are not associated with heat on H3's to my knowledge. On my '08 H3 Alpha, the following applied, I think it still applies to 3.7's but you should consult your owner's manual:

3/4 on the temp gauge is not abnormal at all for an H3. I saw mine run in that range several times, just driving around town on hot days. Only when you get to the red mark and / or get an "ENG HOT" in the display is the truck running too hot. At that point the AC will shut off to ease the strain on the engine.

Definitely get your engine oil checked out as soon as possible.

Sometimes, when you have "cheap" non synthetic oil, when the temp goes up, it loses it's viscosity and the oil pump loses pressure, setting off alarms.

Thanks guys. Awesome, I never thought that it could be the oil although the alarm sead OIL. :emb: Will do that asap. When I saw the temp rise, I thought the oil alarm would be the trucks way of telling me its overheating. The AC works 100%. No problem with the AC and it kept on running. I have to say that I did check the oil but the level was fine. I even added but it kept on giving me an alarm. I will check the gearbox....... Thanks a mil. Awesome advise.

Hi ZachH3

It was normal for my 3.7 H3 to go to 3/4 when pulling my trailer, if you get yourself a OBD2 scanner and monitor the radiator temp, you will be a bit more relaxed my needle would go to 3/4 but the actual temp would be 99C. Just get the oil levels checked, and beware most fuel stations only stock Dex III :shame:so rather go to GM for the right stuff :thumbs:

Thanks allot man.:cheers:

I think that would be the best. Spoke to the guys from Wesvaal and they sead I'd better bring it in so they can rig the comp on. I see you are also from South Africa. Where about?

Good luck, please let us know how things turn out

Hi guys. I posted a new thread under "Help". My truck got sorted and then all of sudden it started again. I changed thermostate, oil, filters and the oil pump and after doing some driving started all over. Will you guys please refer to that tread an if possible give me some advise. Thanks a lot for your help because I don't know if our mechanics know what they are doing.....

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Can007 said:

Is the gauge actually going into the red??? I took my H3 to the dealer because my truck was always running right on the 3/4 marker, I thought it was overheating but the dealer told informed me that’s how H3 run but I had it tested anyway, I have used it like that with no problems. Now the oil sign is a different issue, does the alarm go away when u step on the gas while driving and turn on when u let go of the gas or stopping??? I had a similar issue with that.

Click to expand...

Hi there. I got my truck back today. The temp was always below the half mark. When I towed my boat up a very steep and long hill, the temp went up to just below the 3/4 mark. It then gave me an "oil" alarm. (Indicating low oil pressure). I stopped and it went silent. Since then the temp stayed above the half mark. All was otherwise ok. I took the truck in to get it checked out and they told me the oil need to be changed. So I changed the oil and filters.

Since then, the temp kept going to just below 3/4 and then an "oil" alarm. Lang story short, changed the oil switch, thermostat, oil pump, got the radiator tested. Cost me n bucket full money..... I left the garage and 10 minutes later oil alarm again. At this stage, it doesn't give me an alarm when the car is getting hot, but when I stop.

They changed the battery when they changed the oil and never cleaned the spill. I then took out the batt, all the covers, and found a part of the elect harness between the batt and fuse box. I opened it and foun 9 damaged wires. I then fixed them. Took it back and told them what I did, and then they started to look for elect problems. They went trough all the wire and found nothing. They then got a mobile comp system, rihgged the truck up and drove the whole day till it gave an alarm. Earth fault on a sensor. So they cleaned it and all ok. The temp stays between half and 3/4 and their plan to sort that is to install an additional cooler system for the gear box.

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Glad you got it fixed up. It appears that the "overheating" and the oil were two unrelated issues. Actually, I would say that you never had an overheating issue in that running at 3/4 is normal under load or in higher heat. My temp gauge is "normal" for about six months of the year at just above 1/2. Nonetheless, a separate transmission cooler can be beneficial.

I agree. I'm going to look into an additional oil cooling system. I still don't know why my truck always ran below half and since the alarm, above and up to 3/4. At least the temp of the oil and water is fine. Thanks allot for all the support.

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