Solution to H2 overheating problems

[Michael Baker]

I live in Ecuador, and often drive up the Andes mountains to heights of 14,000ft as well as driving an hour and a half to the beach at 90mph in temperatures of 90-100 Fahrenheit. My H2 has a Vortech Supercharger, I have taken out the catalytic converters for even more power (makes a BIG difference), and I have installed four HID spots in front of the radiator grille. So if anyone should have overheating problems, it is me!

Before making the changes detailed below, I observed that when pushing the car hard the water temperature would rise above 210 to 230/240, and only went back down to 210 when I lifted the foot off the accelerator. The transmission oil temperature would also rise to 230/240 and remain there, even after lifting the foot off the accelerator. I have always used synthetic transmission fluid (Mercon 5), so I hoped that no permanent damage would be done to the transmission.

After reading innumerable comments on the Elcova web site, I did the following:

• I replaced the stock water radiator with a much larger aluminum one from BeCool ($800). This radiator includes the transmission oil heat exchanger. After replacing the radiator the water temperature never once budged from 210, however the transmission fluid temperature still rose to 230/240
• After reading carefully the description of PhilD ( http://www.*******club.com/tech/tranny_cooler_2.html ), where it seems that the solution given did not completely solve the problem, I decided to replace the stock transmission cooler with the largest one that would fit between the supercharger radiator and the air conditioning radiator. After extensive research, I chose the Tru-Cool MAX transmission cooler #4739-1 (without the external thermal bypass - Bulkpart.com $105). This transmission cooler is much larger at 8 1/2 x 22 3/4 x 1 1/4 inch than the Hayden 405 (10" x 15.5" x ??) installed by PhilD. I also replaced the stock transmission pan with the larger pan PML-9427 ($170 from Trail Duty) and installed a heat shield to cover the upper part of the exhaust as it passes under the transmission pan (THE-11630 Summitracing.com). After all these changes, the transmission fluid temperature fluctuates between 150 and 180, but never rises above 180.

Obviously all this costs, but I no longer have to worry about overheating problems!

I attach a photo of the installed transmission radiator and another of the new pan and exhaust heat shield.

[Dug]

Good information , thanks.

[HUMMERcustoms.com/TAZ]

Michael have You installed the 160 degree engine thermostat? This would be a very good upgrade. Can be done in 10 minutes and can get it from LIG as You did You gauge set.

TAZ

[GLBLWARMR]

Originally Posted by HUMMERcustoms.com/TAZ

Michael have You installed the 160 degree engine thermostat? This would be a very good upgrade. Can be done in 10 minutes and can get it from LIG as You did You gauge set.

TAZ

Is there any reprogramming that needs to be done to the computer when if you switch from the stock temperature thermostat? I swapped out one in another vehicle and because of the change I throw everything out of whack. The engine started running to rich and stalling out. I had gone from a 185 degree thermo to a 135 thermo. Once I switched back to the 185 thermo all the problems were fixed. Just curious if this was a problem with the H2??

[tomp]

MB, where did you get the heatshield from?

[Michael Baker]

Heat shield was obtained from Summit Racing:

http://store.summitracing.com/egnsearch.asp?Ntk=KeywordSearch&DDS=1&Ntt=THE%2D11 630+&searchinresults=false&N=+115&y=12&x=22

[H2 Bill]

Michael, not to change the subject but in the picture I can see your hood cable with the rubber tube or "coating" on it. Those tend to hold in the moisture thereby corroding the cable causing it to break. Can be kind of a scaring moment...The new replacement cables don't have the rubber on them.

[H2 Bill]

Mine were literally "white powder" inside after they broke.

[Michael Baker]

Where online could I get the new straps from?

[PARAGON]

As Phil can attest, mine are still in good shape because I spray mine with some anti-rust lubricant I use for everything.

[HUMMERcustoms.com/TAZ]

Originally Posted by GLBLWARMR

Is there any reprogramming that needs to be done to the computer when if you switch from the stock temperature thermostat? I swapped out one in another vehicle and because of the change I throw everything out of whack. The engine started running to rich and stalling out. I had gone from a 185 degree thermo to a 135 thermo. Once I switched back to the 185 thermo all the problems were fixed. Just curious if this was a problem with the H2??

Sorry for late reply. Holidays really messed up time. I would only lower the thermostat temp if I was in a normal condition with engine temp. and went to programmer that would in turn allow Me to run cooler thermo by telling computer you were doing so. Of course at same time getting the benefits of other options of programmer.

The only other way I would run cooler T-stat with stock tune is if You are in a hot temp part of the world and needed the cooler T-stat to try and get to a cooler engine temp and maintain a stock engine temp.

TAZ