Running hot in the mountains

chrismc · **Posted:** Mon Sep 10, 2007 6:11 pm

This past week and a half I was running trails in Ouray, CO and Moab (pics coming soon in another thread after I get them uploaded). In Ouray, most of the trails are around 10,000' altitude (or higher), and I noticed that on extended uphills in 4LO the engine temp gauge would start to creep up. It was never anything that running the heater on HI couldn't take care of, but I wasn't thrilled about it. My guess is that it was due to the lack of airflow over the radiator, but I encountered the same thing crossing Vail Pass on I-70 at about 65mph. I had no problem with engine power (the CRD was just cruising along), but it was starting to get hot. At first I thought it might have been due to mud/dirt in the radiator (I've had that problem on past vehicles), so I flushed out the radiator fins with the garden hose after the first day I noticed it. The water came out clean, though, so I don't believe there was any mud restricting the cooling.

Also, I noticed that after driving for awhile I would start to smell what I believe was the transmission. It wasn't an engine smell that I've noticed before, and it definitely wasn't brakes (I know that smell, plus it was on the "up" side of the trail). I've previously only had manual trannys, so I don't know what an auto smells like (I *do* know what a burnt clutch smells like, though). Additionally, when the tranny started to stink, the shifts started to get rough. It would hang in 2nd gear for awhile before very abruptly shifting into 3rd. I'd rarely get going fast enough to get to 4th (this was all in 4LO). The problem seemed to always be on the 2-3 shift. I even noticed it a couple times in 2HI on the way back to town after the trails. It never seemed to be a problem when first starting out in the morning.

Has anyone else seen problems like this? Are the tranny problems likely due to heat as I suspect?

Are there any aftermarket radiators and/or transmission coolers that might help? I'd really like to not worry about this. The weather was pretty cooperative on this trip (highs <80), but it could be a big problem in warmer weather.

Aside from the engine heat/tranny problems, the CRD did awesome. I was with 2 (much more modified) Xterras and an 07 Wrangler (rental). The diffs in the CRD seemed to "grab" much better than those of the Xterras, and I was able to climb over obstacles with much less tire spin than them. The CRD also gave me much better low-end torque to get over the nasty stuff (especially important at 10,000 feet). I didn't have nearly the ground clearance of the Xterras (they had 33" and 35" tires compared to my 31's), but I managed to keep up just fine. The only other problem I had was a slashed sidewall on the first day out on the trails. It was really sad to see a TrXus with <1000 miles on it go in the dumpster. I managed to pick up a (very) used spare for $20 in town, so luckily it didn't ruin the trip.

DarbyWalters · **Posted:** Mon Sep 10, 2007 6:31 pm

Transmission heat could have caused both the problems since the tranny cooler runs near the radiator. The stock Torque Converter seems to be a possible "weak point" with the CRD. I wonder if the SunCoast TC upgrade would stop this by keeping engine speeds down since it locks up earlier and stronger? The stock TC might have caused the engine to run faster (higher revs) than it should. That could have made it run a bit hot too...

Sir Sam · **Posted:** Mon Sep 10, 2007 6:31 pm

The engine warming up is pretty normal, I observe the same thing all the time around ouray, even then it doesnt creep too high.

What you describe does sound like a trans getting hot, I've experienced the same thing when running in 2hi on trails in ouray, never really had the problem with 4hi though.

I am not familiar with the trans cooler on the CRD, I cannot say if it is really large enough for that type of use.

hatchetman · **Posted:** Mon Sep 10, 2007 7:18 pm

This is why I added a aux tranny cooler. I don't do off roading, but due tow a 5000# toyhauler. Still have original torque converter and 29,000 miles on the libby. The aux trans cooler is mounted up high and on the driver's side.

BBB · **Posted:** Mon Sep 10, 2007 8:38 pm

We dislocated the plastic engine cover, hood sound mat, skid plate sound mat and skid plate to get the air flowing better in the engine compartment. I must admit that the engine cools down much faster than before. I could open the hood an hour after getting home and the engine would still remain almost too hot to touch. Now it cools much sooner. Don't know if it will help a moving vehicle cool better or melt the paint on the hood. :shock:

Our Dodge RAM CRD has no hood sound mats from the factory due to cheapness?.
Running without the skid plate would not be recommended for off road, but a road trip might warrant removing the two front recessed bolts and loosening the rear two slotted skid plate bolts to slide the skid plate off along with the other noise deadening/ heat retaining crapola. We'll just put the warm fuzzy sweaters back on in the winter

Sir Sam · **Posted:** Mon Sep 10, 2007 8:58 pm

BBB wrote:

We dislocated the plastic engine cover, hood sound mat, skid plate sound mat and skid plate to get the air flowing better in the engine compartment. I must admit that the engine cools down much faster than before. I could open the hood an hour after getting home and the engine would still remain almost too hot to touch. Now it cools much sooner. Don't know if it will help a moving vehicle cool better or melt the paint on the hood. :shock:

Our Dodge RAM CRD has no hood sound mats from the factory due to cheapness?.
Running without the skid plate would not be recommended for off road, but a road trip might warrant removing the two front recessed bolts and loosening the rear two slotted skid plate bolts to slide the skid plate off along with the other noise deadening/ heat retaining crapola. We'll just put the warm fuzzy sweaters back on in the winter

How does this affect the engine temps during cold weather(>30F)?

Pablo · **Joined:** Thu Feb 02, 2006 10:06 pm **Posts:** 1201

hatchetman wrote:

This is why I added a aux tranny cooler. I don't do off roading, but due tow a 5000# toyhauler. Still have original torque converter and 29,000 miles on the libby. The aux trans cooler is mounted up high and on the driver's side.

Do you have a pic of the tranny cooler? I am looking into doing that and into putting some vents in the hood. I just don't see enough space up there to sneeze, let alone put a tranny cooler.I was thinking about around the frame rails on the underbody-- but then I have to shield it from rocks and find a way to get air to it-- so I am not liking that either. Those tiny tranny coolers from summit racing do look promising, however.

hatchetman · **Posted:** Tue Sep 11, 2007 1:20 am

Pablo: I mounted the aux tranny cooler by epoxying in four studs for mounting at the back of the black grill mount/reinforcement, driver's side up high. I'll try to get some pics in the morning or afternoon and email them to you if I am unable to post them here. Wasn't a real hard job, just time consuming.

retmil46 · **Posted:** Tue Sep 11, 2007 10:16 am

Look underneath the front bumper where the tow hooks are mounted. Large recessed opening there, just in front of the stock tranny cooler lines. You can easily fit a sizeable frame rail or heat sink cooler in there, has good air flow at speed and also pulled in from the stock fans, fairly well protected from rocks/debris. And at either end of the bumper, there's a sizeable opening where you could route hoses to behind the radiator to tie into the stock cooling line.

I used a couple of short flat brackets on the inside mounting bolts for the tow hooks, and installed a Permacool Junior Frame Rail Cooler (18" long by 2 1/2" wide), plenty of room. If you think thru your mounting arrangement, you could probably fit a physically larger cooler if you want - I went with the 18" cooler since it worked nicely with the brackets I already had laying around.

For combined driving with temps in the high 90's, highest I've seen on return from the aux cooler has been 115 F.

chrismc · **Posted:** Tue Sep 11, 2007 4:18 pm

That aux tranny cooler looks promising. Please send me pics as well if you can't get them posted. What all did it take to install it? Did you have to drain/refill the tranny?

On the engine side, I found the DPG offroad sells aftermarket all-metal radiators for some Jeeps, but not ours (http://dpgoffroad.com/engine.htm). They are made by a company called CSF (http://www.csfimports.com/). It looks like they make one for both KJ gas engines, but not the CRD. I wonder if we could talk them into making one for the CRD? They're based in Rialto, CA. Anyone near there?

tugdrivinj · **Posted:** Mon Sep 17, 2007 1:24 am

i just towed a 3000# (roughly) trailer across the country, I-80 to I90. with little or no trouble, the only rough spot was an attempt to go to yellowstone. we started about 5700 feet up and were headed toward the park and the temp went way up no alarms or anything yet but i didn't want to get to a spot i couldn't get out of.

anyway, next day i pulled off the plastic engine cover which seemed to help. i'd love to see the trans cooler pics and does anyone know if there is a lube oil cooler out there seems to me that wuold make the turbos last a long long time.

Running hot in the mountains

Who is online