Noise from underneath

Hey guys,

I have a question about my 1986 Fiero SE V6 ... when I drive occasionally I will get a knocking noise coming from underneath the car right under the driver's feet and sometimes under the passenger's feet. I just have a tune-up about a month ago and they said there was a crack in the manifold ... not sure if that has anything to do with the problem. The car drives fine otherwise ... idles and starts great.

Any information would be helpful.

Thanks,
Mike

Mike,
welcome to AF, and the Fiero posts.
I am not sure what you've got there? are you sure the noise/vibration/or whatever is definitely up front?
sometimes "knock" noises can tranfer through engine/frame/body and just sound like it is somewhere, where it isn't.
really, the only thing up front to really "clunk" is the struts, farther up, almost towards the lights, unless, is the spare loose? take everything out of the front trunk/storage, and drive and see.
is it when turning harsh? or travelling over rough road? or speed bumps?
I was thinking the exhaust pipe sometimes slaps under my chassis when hard running or shifting, but that wraps from the engine, and heads out the back, not up by your kickpanels.
give us more info, and keep us posted.

hope this helps,
chris
nrt racing

Hi, thanks for the reply.

I am almost completely positive that the noise is from up front ... it sounds like something hit the underside of the car under my feet (or on the passenger's side, too). The noise doesn't seem to come in any particular time. I has come most often when I was stopped at a light and it has never come when I was turning. I already took a look at the spare tire area and nothing was found to be moving around.

Very odd ... thanks once again for the reply!

Mike

It may be the coolant pipe that runs from the front to back along the rocker panels (both side of the car). The brackets that hold them in place tend to corrode and fall off allowing the pipe to become loose. There are two brackets. The front one is by the door, the rear is in front of the rear wheel well.

Been there... Done that....
There's an airlock in the coolant system. Sounds like somebody hitting the floor with a hammer from underneath your feet.
Get the back of the car up on ramps or stands and remove the coolant fill cap on the engine. Run it for awhile and top up the system from there. Should take care of it.

Damn, thanks guys ... I REALLY appreciate you fellows taking time to help solve my problem. I'll take your advice and I'm sure that hammer sound will be gone soon.

Thanks!
Mike

way ta go DEX!
learn something new everyday.