88 G.M. clicking noise

[BrianLas]

Yeah my '88 Grand Marquis is making a clicking or rattling noise from the passenger side under the engine. Not too sure what it is.

[6502dude]

Originally Posted by BrianLas

Yeah my '88 Grand Marquis is making a clicking or rattling noise from the passenger side under the engine. Not too sure what it is.

Pretty hard to diagnose without any details.

There is big difference between a rattle and clicking.

When does this occur? Motor running / at idle / around town / highway speed?

Is car in gear when problem occurs?

Does noise occur all the time or occasionally? Does it occur when you go over bumps? Does it occur when you are turning wheels?

What have you done to determine source?

[BrianLas]

Sorry about the vagueness, i was in a hurry. It occurs when i am in drive, and I am accelerating. I have put it in neutral and revved the engine and it does not make a sound. Nothing different happens over bumps or on turns. It happens every time I accelarte though. The harder I accelerate the louder it is.

[BrianLas]

It is a rattle and I took it to a local shop that didnt really find anything wrong with it, fixed a n air leak, which didnt really solve the problem

[33Chev]

Sounds like you have an exhaust leak (very small)..when you accelerate underload..the engine shifts opening up an exhaust connection (leak). Looks for black coloring around the exhaust manifolds and joint connections! Sounds like a clicking or tapping noise!


P.S. Buy my 91 GM that is posted and you won't have the problem !

[BrianLas]

I have a question though, if it is just an exhaust leak, wouldnt I still hear the sound if I was in neutral and revved the engine?

[33Chev]

Basically with the engine in neutral...there is no torque in the drivetrain, the tranny, driveshaft and exhaust system are essentially just sitting there. When you shift into gear or accelerate..the entire drivetrain and exhaust system is being torqued and loaded up.

Kinda like a rubber band theory , it is stretched when in gear and relaxed when in neutral.

I'd look at the point where the exhaust manifolds bolt to the heads...the manifold may have warped, loose or broken bolt, pipe gap etc.

[BrianLas]

Yeah, I had some work done, there were a few things that needed to be welded down. It sounds fine now