Car People - GM Z55 Suspension question

The Coffee Shop
1

I recently purchased a 2007 Escalade ESV. It has pretty high miles, but I calculated engine / transmission repairs into the purchase cost.

I do have a question about the suspension. Part of the reason I bought it was to pull our 7500lb travel trailer. I bought a set of airbags for the rear suspension to help level it better, but have not installed them yet. After I bought them, I started looking closer and realized that it came with the Z55 AutoRide suspension option. The front has been deleted, but the rear seems to be in place but not working (back end sits real low with the trailer attached and no stabilizer bars, and I have never heard the compressor working). The levelling bars on the trailer help, but not as much as I would like.

Which option would be better for me, repairing the factory suspension and getting rid of the airbags, repairing factory and also using the airbags, or go with a conventional aftermarket shock setup and use the airbags?

2

It has been 10 years since I owned a vehicle with Z55 on it, but I remember a few things that strike me as strange in your post:

Auto ride had 2 separate functions - it controlled loading and dampening of all 4 shocks, and it load leveled only the back using a compressor. When you say the front has been deleted what do you mean? There was no levelling on the front, and I think the shock control system was for all 4 corners - you couldn’t delete the front.

There was a special light on the dashboard for Z55 that gave codes for problems. Are you getting a code?

Finally, the compressor is in the wheel well in the back right of that vehicle. They had a habit of burning up because road debris would kick past the protector. Before that happened they usually blew the fuse. I seem to remember there are 3 - On in the unit, one in the control circuit line, and one in the fuse block for the whole thing.

I would check the fuses, then do a resistance check on the compressor motor, and if both of those are fine or didn’t fix the problem I would take to a GM shop and ask them to look at it. It they are honest they should give you a good guess of what is wrong and how much it will cost for free or very little money, but don’t be surprise if they tell you it isn’t worth fixing.

3

It has been 10 years since I owned a vehicle with Z55 on it, but I remember a few things that strike me as strange in your post:

Auto ride had 2 separate functions - it controlled loading and dampening of all 4 shocks, and it load leveled only the back using a compressor. When you say the front has been deleted what do you mean? There was no levelling on the front, and I think the shock control system was for all 4 corners - you couldn’t delete the front.

There was a special light on the dashboard for Z55 that gave codes for problems. Are you getting a code?

Finally, the compressor is in the wheel well in the back right of that vehicle. They had a habit of burning up because road debris would kick past the protector. Before that happened they usually blew the fuse. I seem to remember there are 3 - On in the unit, one in the control circuit line, and one in the fuse block for the whole thing.

I would check the fuses, then do a resistance check on the compressor motor, and if both of those are fine or didn’t fix the problem I would take to a GM shop and ask them to look at it. It they are honest they should give you a good guess of what is wrong and how much it will cost for free or very little money, but don’t be surprise if they tell you it isn’t worth fixing.

The front are standard shocks with a resistor-looking thing plugged into the wiring harness that would normally attach to the top of the shock. I need to look again to see if the rear has that as well.

I checked the fuses in the fuse box (three of them), all good.

No codes which is what is throwing me off.

I need to crawl underneath to get a better look, but last time I was under there it looked like the rear shocks still had the air lines attached.

I am more interested in the ride levelling on the rear than the 4-corner control, and have found some packages on Amazon that have passive gas shocks that still have the air-ride, and a new compressor. At the end of the day, I just want better load levelling when I am towing. The ride overall is still pretty excellent.

I only have one GM dealer within an hour drive, and I don’t trust them. Three years ago they told me my car needed a new motor immediately, I chose to not change it and it is still running fine today.

4

With a properly-installed weight-distributing hitch (not just stabilizer/sway bars), the Escalade should sit pretty close to level.

Problem is, with airbags or with a properly operating air suspension only, you’re potentially putting too much weight on the rear wheels. That weight needs to be shifted forward (via the WD hitch) or you could have serious problems towing the trailer (understeer, braking).

Might want to check in with your GM dealer or reputable hitch installer for advice.

5

I will still be using my WD hitch. I just want to “assist” the hitch a bit too.

My hitch is similar to (but not exactly like) this.

6

Three years ago they told me my car needed a new motor immediately, I chose to not change it and it is still running fine today.

I can’t help on your suspension question. But about 15 years ago I had a GM dealer tell me the same thing about my 97 Suburban. Said leaking intake manifold seal might have put water into the engine and the main bearings could go at any point without warning. I said let’s see if the oil is milky. It wasn’t. He said that was because the dip stick goes to the bottom and water would be on top of the oil.

I got 150 thousand more miles out of that engine.

7

Three years ago they told me my car needed a new motor immediately, I chose to not change it and it is still running fine today.

I can’t help on your suspension question. But about 15 years ago I had a GM dealer tell me the same thing about my 97 Suburban. Said leaking intake manifold seal might have put water into the engine and the main bearings could go at any point without warning. I said let’s see if the oil is milky. It wasn’t. He said that was because the dip stick goes to the bottom and water would be on top of the oil.

I got 150 thousand more miles out of that engine.

Mine was actually on my Cadillac CTS. Wife took it out of town for a long weekend. Never checked the oil. It started making weird noises, but she kept driving it home. I poured 5 litres of oil in before it showed on the dipstick. No sign of it leaking anywhere, undercarriage and exhaust both looked clean, all other fluids were fine. Took it to the dealer, they said one cylinder was low on compression, but there were no engine codes being thrown for anything. They said complete motor failure was imminent and I needed to replace it. I add an extra litre of oil every two months or so, do regular oil changes, and it still runs fine, 45,000 km later, and has never lost oil that quickly since. We still have no clue what happened, its almost like someone drained it out overnight.

I didn’t buy this Escalade from that dealer, and will be avoiding taking it to them for anything if at all possible.

8

He said that was because the dip stick goes to the bottom and water would be on top of the oil.
Water is denser than motor oil. And dealerships wonder why we vanish as soon as the factory warranty expires.