Air suspension issues

[agon3279]

Man this is really ticking me off The past two weeks ive had and issue with the air suspension. I don't know if its caused by the cold or what, but i'm at a loss. So, last week i noticed that the back end was sagging and i thought it was the internal check valve. Then i did some research and found that sometimes in the extreme cold the shocks won't air up. So the next day i drove to work and parked in the garage. When i picked up my truck, I noticed that upon starting it, the back end raised up. Now a week later I'm having the same issue. But today's temp was above freezing so I have no idea what the problem could be. All i can think of is that the internal check valve is frozen shut, or the solenoid is frozen shut. Any Ideas would be greatly appreciated. And I did check the lines and air springs. There is no leak anywhere.

 

[jrSS]

Any Ideas would be greatly appreciated.

Swap the bags for springs. I did. Much better. Wont have to worry about the compressor filling bags.

 

[linneje]

I don't think the cold is the cause of the issue - rather, the cold is causing the issue to be more pronounced. For as long as I have had the Envoy with the air suspension, we here can have the temp go below -30, or swing 20º up or down over a day. I have never had a problem like you are describing.

We are pretty dry here in the winter, so it may be a condensation in the check valve that is freezing and causing it, though, if you are more humid there. Or, it could be that the compressor is starting to die, and the cold is making that happen faster.

I am not sure how you would diagnose a check valve when it is cold, though, other than waiting for warmer weather.

 

[RedEnvoyDenali]

Are these the original bags? I had a similiar problem to what you described and I live in an extreme cold climate. My truck would be sitting down when i came out in the am and then pump up and be fine. What has happened is the rubber from the bags finally rotted to the point where they leaked air and with out the pump running they would deflate to sit the truck down on the stops.

Solution was to purchase a set of Arnott replacement bags. 2-3 hours to install, guaranteed for life (we will see). Some folks suggest switching to springs, i really like the bags for both ride and adjust ability. When i put a trailer on the hitch the back end stays at the proper height no matter what. A word of caution, don't leave it too long. The compressor has to work overtime to keep the leaking bags up and will self destruct in a short time causing a large outlay of $. By the way I went with Arnott replacement bags not the GM OEM one's they sell. The GM are doomed to fail again and the cheaper price won't seem so good the second time around. Remember Arnott's replacement bag has lifetime warranty (non tested at this point).

If your 05 is just getting to having leaking bags now you have done well, the normal lifespan of the OEM GMC bags was about 5-6 years.

Good luck i hope this helps you determine what you problem might be.

 

[floridafitz]

2nd the motion to swap for springs unless you absolutely need air bags for big load variations or towing....even then there are spring over bag options. The spring-only ride degradation is minimal IMHO. Did mine a few years ago and never looked back. No more disappointments and costly repairs.

 

[linneje]

I actually agree with both of the previous posts ... if you are keeping the air suspension, and you have a 2005 you will surely be replacing those bags soon whether or not they are leaking now. So replacing the bags is a good start - it can save the compressor from fail, and it is something you can do yourself, so it is not that expensive.

My tire shop told me my originals were starting to rot, so I put Arnotts in myself even though there was no leak yet. I use the Envoy for towing, so it is nice to have the back end come back up to the same level ... it works really well for me.

If you are not towing, why would you want to keep them? You could replace them with aftermarkets that do away with the air suspension, which could save you costly repairs down the road. I still have my original air compressor, but if it goes that will cost some to replace it - I am willing because I like the air suspension for towing, but you may not want that.

It depends on your personal preference. If you are going to keep the air suspension, though, I would replace the bags now.

 

[agon3279]

Well, I do tow but not very often. I know this past summer I had to tow a horse trailer and a few other times a trailer full of bounce houses. I figured that today may have helped since the weather went above 40 today but still it didn't. I did however go and take the compressor off. I didn't fully take off, but it seems to be in fairly good shape. There is not a whole lot of corrosion anywhere on it. It was full of road salt and things of that nature since it did snow here in Chicago recently. I know that when i bought the vehicle that the compressor was quite loud. I figured that it was just normal operation since the air springs were working. Should I have taken that as a sign that something could potentially be wrong?

 

[agon3279]

WOW! Now i really am clueless! I just went to tinker around with the system again. I took the pump off but didn't disconnect any air lines or connections. But what i did do is loosen the air fittings on the the pump and bleed some air out. I buttoned everything up, then started up the truck. But nothing happened. Then I pulled the fuse a few times then nothing happened. While the pump was working i pulled the fuse again and put it back in. And voila! suddenly the back end started to rise up. Now, i'm thinking that its a solenoid that has gone bad.

 

[linneje]

Well, I do tow but not very often. I know this past summer I had to tow a horse trailer and a few other times a trailer full of bounce houses. I figured that today may have helped since the weather went above 40 today but still it didn't. I did however go and take the compressor off. I didn't fully take off, but it seems to be in fairly good shape. There is not a whole lot of corrosion anywhere on it. It was full of road salt and things of that nature since it did snow here in Chicago recently. I know that when i bought the vehicle that the compressor was quite loud. I figured that it was just normal operation since the air springs were working. Should I have taken that as a sign that something could potentially be wrong?

I felt mine was loud when I bought it five years ago too. But I have not had to replace it yet, it still works great. Sometimes it seems quiet and other days louder but I think that is just normal. I sometimes stand outside and watch it raise slightly when it starts, just to verify.

 

[linneje]

WOW! Now i really am clueless! I just went to tinker around with the system again. I took the pump off but didn't disconnect any air lines or connections. But what i did do is loosen the air fittings on the the pump and bleed some air out. I buttoned everything up, then started up the truck. But nothing happened. Then I pulled the fuse a few times then nothing happened. While the pump was working i pulled the fuse again and put it back in. And voila! suddenly the back end started to rise up. Now, i'm thinking that its a solenoid that has gone bad.

It sounds more like you have a wiring or ground problem that is intermittent. That could be tough to diagnose. Someone else here could chime in about whether a code reader (the expensive ones) could find a code relating to the air suspension system is kept in memory. My code reader will only read emissions codes.