Another trans cooling thread...

[06 H3]

Today was in the 60s. For me I seem to run hotter then most others. I can pull 200 degrees in 50 degree weather. 2 weeks ago heading up a grade with a strong headwind I pulled 230 in 55 degree weather.

Once I am warmed up and driving for a while the minimum temp I will run is 160 as the stat would start to bypass. In the summer we will hit 110 degree weather and I climb some grades at freeway speed daily. It will get a good test so I will be reporting back. If I need more cooling I'll add a 2nd cooler like reloader did. After putting one in I realized it would be easier to stack 2 small ones then mount one big one.

 

[digglesworth]

That's the biggest difference I noticed in comparing several models. Some were 3/4" thick and some were 1 1/2" thick. As soon as my cooler gets here, I'll be doing the install.

 

[Medic_Morgan]

Not to derail this thread but I'm interested in seeing what my trans temps are. How do I program my ScanGauge to see it? I'd like to start tracking this since I recently had Tustin replace my cracked radiator(under warranty thankfully!) and I wanna make sure I'll make Moab safely this year


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[Best4x4]

After all this cooling issue/trans stuff I checked my 07 Adventure and I swear the transfluid has a slight orange color to it...... If I was getting DexCool in my trans wouldn't it turn milky vs just having a slight orange tint to it? It smells like trans fluid, but I DO NOT WANT to have my new Hummer blow a trans!!

It also raises the same question I had a while ago when I just had my Alpha. Is this just a transcooler line failure with the OEM radiator?? Or is it even happening to aftermarket models? I can see one maker like ACDelco having an issue, but I don't see how every single company would have the same issue. I can get an aftermarket radiator for 130.00

I have an aftermarket cooler laying around from my 05 Jeep Wrangler that I never installed. It's about an inch thick and maybe 10x12 in size. I could mount it in place of the OEM cooler, but which line is in/out on our OEM setups?

Also if I drop the pan on the H3 and change out the fluid and filter I'm not going to get all of the old fluid out since some will still be in the convertor. Will that work or do I need to have it professionally flushed after I drop the pan and change the filter myself?

I'm going to look at the fluid one more time, but if my eyes aren't playing tricks on me I swear it has a orange tint to it vs red

 

[06 H3]

The lines have never been an issue until recently when some started posting the lines are leaking. Even then that's not the main issue. the main issue is contamination. If the rad cracks and gets into the trans cooler your screwed.

That's why a lot of us are running thermostats to help with warming up the trans and completely bypassing the oem cooler. Now you have the added piece of mind that if the rad leaks you can still drive as long as you watch your temps. Without a cooler I was skeptical to risk driving and killing my trans

 

[06 H3]

Medic I have the code to do the temp on the scan gauge. I'll explain how you do it too...just need to look through my phone to find it.

 

[Best4x4]

Thats the part I guess I am clueless about.. Isn't the cooler in the oem radiator just a metal finned line running thru the lower tank? How can the radiator cracking get into the line unless the actual line is failing? I tried to post a pic via my phone, but I can't.

Dipped my dipstick on a white paper towel fluid looks brownish/orange/red

Dipped into my coolant and it shows up red on a white paper towel.

 

[06 H3]

Thats the part I guess I am clueless about.. Isn't the cooler in the oem radiator just a metal finned line running thru the lower tank? How can the radiator cracking get into the line unless the actual line is failing? I tried to post a pic via my phone, but I can't.

Dipped my dipstick on a white paper towel fluid looks brownish/orange/red

Dipped into my coolant and it shows up red on a white paper towel.

If thats the case I would avoid driving it. when I checked mine it was still bright red.

To be honest I am not sure how the oem trans cooler works but I was under the impression it was a small tank inside the rad and if the rad cracks, depending on where it does crack the trans cooler can crack too.

 

[alrock]

Best, the issue isn't limited to GM. A quick Google search shows the same issue with other manufacturers that have transmission coolers integrated into the radiator. I don't think it's an offroad issue either. For example, Cotilo's H3 has never seen anything more severe than an accidental curb hop and she had mixed fluids but luckily she had an extended warranty to cover the $3000+ repair.

Radiators (and all parts) are subject to fail from wear and tear, poor workmanship or poor materials. My second OEM radiator failed in about 18 months - not a trans cooler fail, but a simple hole in the core on the back side, so it wasn't caused by a rock or something like that. The issue with the possibility of the trans cooler fail is the devastating effect it can have on your wallet vs. a $100 modification to your truck in the form of an external trans cooler. Yes, it shouldn't fail but it can. We can't reasonably protect ourselves against all of the failures that can happen in our trucks, but the risk/reward on this particular modification is certainly worth it in my mind.

I'm not going to spend hundreds on RCV CVs to stave off $60 CV failures, but I'm willing to spend $100 to stave off a $3000 repair. And there's not much of a middle ground if the trans cooler fails - it is catastrophic in its effect.

The aftermarket trans coolers are somewhat universal. You just need to find one that fits your cooling needs and has the appropriately sized inputs if this is a mod you want to do.

 

[Best4x4]

Yep thats why I have to fix this asap. Just worried that dropping the transmission pan, filter change, and new fluid isn't going to get it all out.

I can modify the hoses and connect that small cooler I have in front of the radiator no biggie.

It also looks like my radiator was replaced at one point and maybe they never did the transmission flush afterwards..

It's cold here so I may bypass it for a test and see if coolant comes out of the trans line in the radiator to be 100% sure wth is going on.

I'm used to seeing a metal finned line running thru the lower tank. Radiator can totally blow out, but the two never mix due to aluminum line ran thru lower plastic tank. The only way that would fail would be corrosion to the aluminum line inside the tank, a wreck where both are damaged, or a bad weld, most I've seen are a solid line with threaded ends with no welds.

If it's a plastic tank with metal line connectors in our radiators then that is just "CHEAP" and stupid.

On my 94 Range Rover and 97 Discovery they had a stock setup with a long external coil type cooler mounted just behind the grill.

My wife has to drive it until I can do something to it over the weekend. I am sure it's been like this since before I bought it. Doubt a few days is gonna be the end of it all the sudden.

 

[alrock]

Forgot your other question.
Many people are against trans flushes on older transmissions as you stand a chance of dislodging stuff that might want to stay lodged. A pan drop and fill will get about half of the fluid, and that's still a good improvement.

 

[Best4x4]

Yeah I've heard flushes aren't all that great, but neither is coolant in the transmission fluid, I just don't wanna drop the pan, replace the filter, re route the cooler to an external one, then top off the fluid and still have it blow up 2k down the road.

One last question, should the external cooler be mounted between the radiator and HVAC condenser or in front of the HVAC Condenser? I'd think it would reach temp faster between the two and cool closer to OEM vs sitting out front of it all.

I am shopping for a trans filter, line for my external cooler, and fluid which I am guessing is Dexron VI.

 

[poncho1965]

In front of the AC condenser. I did install a bypass valve. My observation so far with the external cooler is that the trans fluid heats up just as fast as it did when it was in the radiator.


Mike

 

[Best4x4]

Okay in front she goes, and I just got a new filter, gasket, and 8 quarts of full synthetic VI.

I will be bypassing the OEM setup 100%. If it leaks coolant I'll know it was INOP and then I'll just cap the fittings on the Radiator.

Hope thats good enough to save it!!

 

[Best4x4]

Okay I just got done, and now that I've seen the radiator from top to bottom, I can now say the only way you're going to get coolant in your transmission is if the aluminum block cooler inside the radiator fails (rare or a factory defect), or if the O-Rings around the transmission block cooler, and transmission line O-Rings fail. The plastic tank cracking will not effect the transmission setup unless it causes the O-Rings to fail. From what I could tell with my situation one of the O-Rings on the transmission line end was not seated properly (going to guess from a transmission flush or previous owner repairs).

I cut my OEM lines by the oil filter, connected my rubber lines, routed it to the right side of the radiator along the frame. Then I mounted the transmission cooler behind the horn as high as I could get it. Dropping the pan wasn't all that hard, but the one thing that ticked me off was when I replaced the transmission filter the OEM one came out without the seal on it (it was still up inside the transmission), and I couldn't find the new one to save my life. I just installed the new filter with the original seal (it fit nice and snug), and after I had it all back together and running guess what I found in my Auto Zone bag? lol.

I didn't get a chance to test drive it, but I do have a Scangauge II in both my H3's so I'd love to know how setup the trans temp on both of them.

 

[Best4x4]

Drove the Hummer today and after about 15 miles I got a P0128 fault. It's been in the upper 30's here and while going 65MPH the max temp the engine got to was 168-172. Not sure if I have an air bubble in my cooling system since I removed the radiator, or my thermostat is stuck open. At idle it'll get up to 180, but that's it at 38F. I'm not at all familiar with the I5 as my Alpha is sitting at 195 to 205F while cruising down the road in the same weather. The heater is warm, and the upper hose feels pretty tight and warm.

My wife and I have a baby shower to go to tomorrow, and I'm going to take the Adventure and see if the P0128 returns. I'm thinking it has to do with me removing the radiator and changing out the coolant vs a thermostat, or with the transmission cooler being separate now that I'll have cooler engine temps, but I didn't think it would be 15F and causing a P0128 and the trans does take a while for the converter to lock/unlock when it's cold. After about 5 miles it's good to go and it drives/shifts normally.

 

[digglesworth]

I could see it being opposite. Cooler trans temps since the fluid isn't cycled through the radiator anymore.... They say the radiator helps to warm up the trans fluid since the engine warms up faster than the transmission.... The engine should be warming up the same as before. There might be an air bubble causing the code. I would hope the t stat didn't just go out in coincidence with changing the coolant. Where is the temp gauge? Mine was throwing a code but the temp gauge wouldn't go above 1/4... After changing the t stat, code was gone and the engine fully warmed up to just above 1/2 on the gauge.
Did you add a thermal bypass valve with your cooler? With temps that cold, it will naturally take your trans that much longer to fully warm up.... I don't think your issues are related. The code is either t stat, temp sensor or coolant level. My bet is coolant level. The trans is taking longer to warm up cause it doesn't have a warm radiator to help it along. In that case, a thermal bypass valve can help...

 

[Best4x4]

Well I finally looked online and got the ScanGauge II VPW protocol for the TFT. Showed 89F when I cranked it just a few minutes ago lol, but after driving it the temp was 110F and climbing, but I just made a quick trip around the block. XGauge was easy to tweak I just had to have the right code!

It's gotta be an air bubble, or air pocket that caused the P0128. I don't see how dumping the coolant on a cold engine would mess up the thermostat. The heater puts out fine, and at idle the ScanGauge shows 177-180F. Moving down the road is where it'll settle down into the 168-172F range depending on speed. The gauge cruising down the road is just above a 1/4, but at idle it goes between 1/4 and 1/2. I'll see how it does on the trip to Tomball, TX tomorrow which is about a 2HR drive one way.

 

[digglesworth]

Check the reservoir in the morning. Fill to the cold line. If it was low, you'll know if the reservoir is low when it's totally cold. Drive it on your trip and let it cool off overnight again and check it in the morning. I'd keep an eye on that dash gauge. I know they aren't 100% accurate but that's what told me my t stat was stuck open. I'd only get a code when temps were cold outside. Even in the summer, the temp gauge wouldn't go much over 1/4 but wasn't cold enough to throw a code. Now my gauge sits just over 1/2, which is from what I've heard, normal for the H3.

 

[Best4x4]

Yeah my Alpha with the 5.3L is a much warmer running rig. 195F is cool for it lol.

 

[Best4x4]

Changed the thermostat out and now the engine temp is around 198 to 206 at a stop light. The new thermostat was marked 187F. I'm guessing it has an air pocket in it. I drove it yesterday and let it cool down.

Then my wife drove it to work and she said it was 198 driving and just before she shut it off it was at 210.. If it doesn't start running a bit cooler I'll park it on a steep incline and try running it with the cap off to get the air out.

 

[digglesworth]

Fan clutch may be going....

 

[Best4x4]

Brand new put it on during the tune up.

 

[06 H3]

I haven't updated it much since I installed it back in February. The trans runs at 168 when cruising on the freeway in 60-70 degrees. In 80 degrees I'll hit 190 on long freeway climbs but it cools back down MUCH quicker then oem. In the past I would hit this specific hill I drive on everyday on the freeway and in 80 degrees I would hit 220 by the time I get home 7 miles past the climb I would be at 210 now right after the climb I start lowering the temps where in the past I wouldn't. Overall so far it's been great it runs cooler and when it heats up it still doesn't heat up as much as before and will cool back down much quicker.

Today is 95 out so now I'm getting to the good test. Will keep you posted

 

[RamRod]

Today is 95 out so now I'm getting to the good test. Will keep you posted

Thanks for he update, I'll be watching my temps this summer to see if I need to do the same! (never had a gauge hooked up before)

It hit 59 here today, that's the warmest it has been since October of 2013 hahaha..... I am laughing to hide the tears (frozen tears)

Needless to say, mother nature have been my trans cooler... haven't gone over 170 even after a 200 mile freeway drive...