: Strange vibration - comes on and off - any ideas



kwaobus
09-07-07, 11:25 AM
This has happened to me on 3 occassions now. Car is warmed up, I am travelling along at 40-50MPH nice and flat road and there is suddenly an internal vibration for about 3 seconds, then turns off, comes back on for 3-4 seconds, turns off. It does this about 5 to 6 times and then goes away. Any ideas. Fan? Clutch slipping? Is somethign about to break? :hmm:

Highway Star
09-07-07, 10:23 PM
Does it make an audible sound?

casciomichael
09-08-07, 03:44 AM
Is your level ride system light flickering on and off with this vibration? I remember feeling that vibration on my 93 deville only to find out that it was the load leveling compressor cycling due to leaky struts. I changed the struts and the system works like it is supposed to.

Mike

Wheelman322
09-08-07, 03:55 AM
Really sounds like the level ride to me too. My compressor comes on rarely now since I replaced the rear springs with HD Limo springs and HD air shocks. Before the compressor used to kick on all the time.

kwaobus
09-09-07, 12:12 AM
yes, it makes an audible sound. Also, I don't think I have ride leveling control, wouldn't there be a third belt to drive the air ride?

Wheelman322
09-09-07, 12:18 AM
yes, it makes an audible sound. Also, I don't think I have ride leveling control, wouldn't there be a third belt to drive the air ride?

No. The compressor is mounted on the left side of the header panel and is about the size of a can of soda.

kwaobus
09-09-07, 12:24 AM
this was not standard equipment, right? I don't see the air compressor you described, I don;t think I have this, only see belts dirving the water pump, alternator, power steering, and AC compessor.

carnut
09-09-07, 05:54 PM
Level ride was standard equipment. This compressor is electrical. Its NOT driven by a belt. Sits on driver side inner fender, a small air line comes from it to the left rear shock. Then another line comes from l/rear shock to the r/rear shock. Turn the ignition key to the run position so all the dash indicator lights are on, then have a couple of people sit on the rear bumper. After about 20 to 30 seconds the level ride pump should turn on. Is that the noise? report back.

Highway Star
09-09-07, 06:06 PM
Level ride was standard equipment. This compressor is electrical. Its NOT driven by a belt. Sits on driver side inner fender, a small air line comes from it to the left rear shock. Then another line comes from l/rear shock to the r/rear shock. Turn the ignition key to the run position so all the dash indicator lights are on, then have a couple of people sit on the rear bumper. After about 20 to 30 seconds the level ride pump should turn on. Is that the noise? report back.

I believe it was an option on the Deville line, not standard. So he may not have it. My '79 CDV doesn't have it either.

carnut
09-09-07, 08:31 PM
You could be correct. I started with Cadillac in 81. Every Cad I was familiar with except for the Cimmaron had it.

casciomichael
09-09-07, 08:44 PM
The Automatic Level Control/Level Ride became standard on Fleetwood Broughams in 1965 and was optional on Devilles until 1984. Look right behind your drivers side headlights you should see a grey and black compressor about 8 X 10 inches with wires going to it and 1 grey air line coming out of it. It will be right on top of the Charcoal Canister blocking direct view of it. You should have a green light on your dashboard (presuming the bulb is still good) that lights up every time the compressor is activated.

I hope this helps,
Mike

kwaobus
09-10-07, 12:16 PM
I think I definitely don't have air ride control, there is no compressor where it is supposedly located and no air lines to the rear shocks. I guess that rules out that source of vibration. :ill:

casciomichael
09-11-07, 11:51 PM
I know that federal carbureated 1978 cadillacs did not have a AIR Pump/Pollution pump, but does your car contain a pollution pump? I believe, High Altitude and California Cars had it installed. The pump could make such noises when it is supposed to vent to atmosphere.

Mike