Weird stuff happening--hot desert wheeling...

[Shahram]

Took the Cruiser out to the El Paso Mountains in the Mojave Desert yesterday. 111º-116ºF, dry as an oven, and some weird stuff started happening. A/C was cranked on the 2 hour drive from L.A. to the trail, no problems. Got to the trail, A/C started blowing warm and swampy air every time we stopped or drove slowly. Trail is a moderate windy dirt road with ruts and some small obstacles. Kept it in high range, figured I didn't need low range at the time. Engine temp gauge started rising. Uh-oh. Never seen it go above half way, at least not in the 4 months I've owned it. Put it into low range, turned off A/C, turned on heater, opened windows. Temp came down pretty quick.

We got to the camp site, had lunch, shot some cans, and after a few hours, we were back on the trail. No problems, but I kept the A/C off.

But, then I noticed that the Center Diff Lock light wasn't on, nor was my ABS disengage light on. I was getting a little worried. Tried locking up the brakes, could feel the ABS working. Kept driving to keep up with buddies, radioed that I might need to stop and think this through. Got to a nice lookout point, turned off engine, discussed problem. Everyone shrugged their shoulders. Turned engine back on. Nothing. Turned it off again. Turned it on, again nothing. Turned it off again. Hung out at lookout for a few more minutes, then decided to head home. On the way back down the trail, after about a minute and a half, Center Diff light and ABS light go on magically at the same time, then off, then on, then fade in, fade out, then gone. Two seconds later, back on again, this time strong. Locked up brakes, no problem. Went back down trail, turned A/C back on because the temp had dropped a little and we were going completely downhill. A/C worked fine, unless I stopped. When I stopped, it blew warm and swampy air again. We got to the road, switched out of Low and back to L.A. with no further issues.

Got back to Santa Monica where it was in the low 70ºs and humid. I've been having a "knock" sound (like a low-grade fuel ping) when I first throttle, which goes away at higher RPMs. Now, accompanying that is a low grumble in first gear. When I pull away from a stop, it sounds like a hibernating bear is stuck in the tranny. A/C is also noisy as hell now. I'm a little worried, but I have faith in the Cruiser and know that these problems, once addressed, will be easily remedied. But I'd like to have an idea what's up before I start trying to fix things.

I didn't wheel the Cruiser hard yesterday at all. Just some moderate dirt roads with some ruts and hill climbs. Any suggestions on what these problems are, and if they may be related? Having 'wheeled Nissans for a few years, I learned little nuances and signs that lead one to the source of potential electrical and engine problems (some of which are so far-fetched as to boggle the mind), but the Cruiser is new to me, so I'm trying to figure out which electrical and other components are related, or located near each other. I'm starting over from scratch, basically.

Sorry for the long-winded post, and thanks in advance for any and all help and info you may give. You guys are really helpful and your knowledge and generosity are not lost on me.

 

[IdahoDoug]

What year?

The ABS/center diff lock light are most likely a grundgy switch that can be pulled, cleaned and replaced in about 15 minutes. Do a search for this.

On a hot day like that, I'd have been in low range even for fooling around just to ease the heat load on the cooling system, but that's not your issue.

Sounds to me like you have a cooling system issue that kept your coolant temps bouncing in and out of the red zone, which automatically shuts down the a/c to protect the engine. I'd go through the cooling system completely as that was a clear warning and you got off easy. Next time you might be opening your wallet.

DougM

 

[parabola]

Excuse the possible stupid question and thread derailment, but how does using low range put less heat load on the cooling system?

Edit: Let me hazard a guess. In low range it is less load on the engine to get the vehicle moving and thus less load on the cooling system?

 

[IdahoDoug]

Yep, the engine's loafing to do the same work with torque basically doubled, the torque converter remains locked at all times (less heat generation), etc.

DougM

 

[miked]

Yep, the engine's loafing to do the same work with torque basically doubled, the torque converter remains locked at all times (less heat generation), etc.

DougM

you sure about the torque converter remaining locked? does it lock when in low?

 

[landtank]

Just a thought but a stuck e-brake can make a grumbling noise as well as put one hell of a load on the engine. Does the e-brake lever have some play before there is tension on the handle? Normal would be to pull up about 1/4".

 

[cruiserdan]

You have cooling system issues that need to be addressed.

 

[IdahoDoug]

Mike,

Looks like the year of the vehicle in question will remain a mystery, but I'm pretty certain I read that low range locks the torque converter on both trannies to provide max engine braking in all forward gears. But now you've made me wonder if this is only when coasting/using engine braking. I'll recheck and post.

DougM

 

[Shahram]

UPDATE....

Thanks for all the info and advice. My 80 is a '96 w/lockers. Yesterday, a buddy came by to check it out with me. The "hibernating bear" noise turned out to be my exhaust pipe had broken off a bracket, and is vibrating against the frame, resonating through the truck. It's worse when I take off because of the vibration under torque. Whew! I thought I was having some weird tranny issue. The A/C still sounds like a boat motor, but I now think it's the fan, because it gets louder as you turn the fan higher. It still blows cold, but like I said, it's making a wicked noise, and the noise exacerbates the vibration in the exhaust, so it's pretty loud. I don't know squat about A/Cs, so I'll have someone take a look at it.

As for the heating up issue, I'm thinking it was staying in high range. It was 115ºF out there, and once I got into Low, the temp dropped.

The Center Diff Lock and ABS thing is still puzzling. I went out in the dirt yesterday and tested it out. It worked perfectly. Only difference was it was 40º cooler outside. So I'm thinking it's got something to do with the heat. My Front and Rear Diff Locks were also really sticky, which they haven't been ever before. My Rear Diff took a good twenty seconds before it engaged.

I think you guys are right, though...I am having some cooling issues. I'll flush the radiator and check the system out and see what happens. I've never 'wheeled in such severe heat before, it was a good test to see how things work under those conditions.

 

[miked]

Mike,

Looks like the year of the vehicle in question will remain a mystery, but I'm pretty certain I read that low range locks the torque converter on both trannies to provide max engine braking in all forward gears. But now you've made me wonder if this is only when coasting/using engine braking. I'll recheck and post.

DougM

thanks Doug