GMC Envoy Air Suspension Who is the fix it guy?

Folks, here’s the situation. I have a 2002 Olds Bravada (same as the GMC Envoy) with self-leveling rear air suspension.

The problem is the suspension is leaking down anytime it’s below 20 degrees. the rear end bottoms out with the air spring bags fully deflated. I’m fairly exact on that cutoff line, above 20 everything seems fine. Below 20 F, it won’t reinflate. The compressor runs for 10-15 seconds, shuts off, and won’t re-start.

I’ve had it to the local Chevy dealership and an independent GM Certified mechanic. Neither could find a problem.

But here’s where I get a little frustrated. I already know if you pull the vehicle inside a heated shop, you WON’T HAVE a problem. I tell them that, but then they pull the vehicle inside a heated shop and tell me they can’t find any problem.

Parts for this thing are expensive, so I don’t want to start swapping parts. I need somone who knows what they are doing and who knows how to leak check these systems and how to test the mechanical/electrical side. I need a real mechanic who can toubleshoot, not just a keyboard jockey who can only do what the computer tells him to do.

Does any one know a go-to guy who really knows these systems? East metro preferred, but at this point I’d say give me anyone else as well

Thanks.

Grouse

Have you Googled the problem. Most unusual problems can be found and fixed with Google

Quote:

---

Have you Googled the problem. Most unusual problems can be found and fixed with Google

---

Yes, I have Googled the problem. The answer is “it depends”. Because parts are very expensive (each air spring on its own is $200), I don’t want to start swapping parts and hoping.

It’s a complicated system that must be 100% leak free. So if it’s leaking, There is no substitute for finding the leak or finding out why it’s not inflating.

So I really need the go-to guy who actually knows how to troubleshoot a problem.

Grouse

Put some soapy water in a spray bottle and start shooting the components of the system. Bubbles = leak.

Quote:

---

Put some soapy water in a spray bottle and start shooting the components of the system. Bubbles = leak.

---

Already been tried. No leak below 20 F. Very hard to use soapy water below 20 as it freezes before you can see the bubbles form.

Also, the problem could be a leak inside the compressor OR it could be relief valve sticking open. Or an electrical fault, or, or, or…

I can assure you, all the obvious diagnostics and fixes have already been tried and failed. Hence the need for someone who knows what they are doing.

Grouse

I would guess your bags are dry rotted and when cold they leak. Throw these at em. Great company with lifetime warranty.

https://www.arnottindustries.com/part_OLDSMOBILE_yid12_pid119_gid497.html

I also think taking a better look at the bags,especially around the bottom section that rides over the bag cone.

Im pretty sure, if memory serves me correctly, there is a set of yukon or suburban springs that can be swapped out with the envoy springs, along with a HD shock that will eliminate your issue, and I think its cheaper than replacing the air bags….head over to trailvoy.com or offroadtb.com and check in with the guru’s there. one of those fellas should be able to help you within 24 hours!

Quote:

---

I would guess your bags are dry rotted and when cold they leak. Throw these at em. Great company with lifetime warranty.

---

Negative. Bags have already been bench-tested. No leaks.

Guys, as I’ve said, all the obvious things have already been tried. Times two.

It’s more complicated. My guess is that it’s in the compressor or control system, but as I said, I don’t want to just start throwing $500 parts at the problem, I want to actually know what’s wrong, not just guess.

I know swapping out for hard springs is an option, but again it’s more complicated than just dropping in 2 springs. There’s a whole control system that will light up the dash like a christmas tree if it’s disconnected. Even ignoring that, the quote for swapping out all the parts is over $700.

Grouse

Easy way out is to just put in gas shocks other wise u are just going to shotgun parts into it because there is not a clear cut way to diag a problem like this

It already has gas shocks. This is an air spring suspension, the shocks are the same as every other truck on the road.

Grouse

Grouse,
Had a buddy that had same system and he also said how costly it was for repairs
He went with air shocks to get it by, so he could TRADE it OFF

I am not familiar with these systems, but on my commercial trucks we get ice build up in the compressor/lines if they are not drained occasionally. Just a shot in the dark.

Grouse, did you get this figured out? I have a 05 Rainier with the exact same problem, albeit instead of at 20 degrees, it happens when it gets below 0. I’ve done some test of my own to try and diagnose.
Rear was completely down, fully sagged.
Cycled ignition to see if could raise it; pump runs for 20 secs then turns off. no movement of rear height at all.
Tested air pressure at the toy/tire inflation valve inside the truck. it would reach 10psi then stop there. this told me it has to be a relief valve stuck open/partial since the pump ran fine normally.
Due to fact that I had no issues above 0 (this latest cold snap is what caused the issue) I assume warming the pump would help.
so put heater under the pump and got ambient air in garage to 33 deg.
cycled ignition and pump ran extended duration, and rear end went to normal height.
went to bed at that point.
came back in morning, and height had not changed. so this tells me the valve is closed and bags/lines are not leaking.

This sounds very similar to what you spoke of.
Only thing I can find is a kit that seems to be able to replace the relief valve seal and spring on side of pump. curious on your thoughts on that.

John, your description is with your Buick is the problem I was having, to the letter.

Sorry to disappoint, but no, I never did get it completely figured out and about 3 months after I posted this, the transmission died on me on the way to work and at $4500 for a rebuilt tranny, that was the end of the Bravada. Ol’ Blue died on the side of 94. RIP.

Here’s what I did kida-sorta figure out.

– On returning it to the dealer, they re-tested the air bags (air springs) themselves again and did find leaks. So I agreed to replace the air springs at ridiculous cost, but only if the shop agreed that other future trouble shooting and repair was on them if this didn’t fix the problem.

Well, it fixed about 50% of the problem. The system lost air much more slowly after the air springs were replaced, but it still would let down within 2-3 days in the cold. Since I rarely let my truck sit for that long, it kinda-mainly solved the problem, but I wasn’t happy about it because it was a half-ass fix.

– I also read about that valve kit and I actually bought the kit. The problem was that the screws that hold the valve cover on the compressor were so rusted that I couldn’t get them off. I didn’t want to risk messing up the compressor so I stopped there.

But if I were you, I would absolutely try this solution. The dealer wouldn’t do it because they claimed that this wasn’t the problem. How they knew that wasn’t clear.

The shame of it is I had that kit sitting in a box unused out in the garage I and just threw it away last summer. Sorry, I’d have gladly sent it to you if I still had it. It was like $19.

So the bottom line is I suspect I had 2-3 problems, one of which was the leaking air springs, but I also suspect I had other problems that nobody I took it to was able to figure out.

Good luck. Sorry I can’t point you to a sure fire fix.

Grouse