all of a sudden it clatters like a diesel... :(

[thirdman]

My Festy has been running great for a long time. Recently I had an idler pulley start making nasty grinding noises, so it sat unused for about a month while I delayed fixing it.

I finally got around to it, and now it makes a very distinctive knocking/clattering noise that sounds just like a little diesel engine.

It starts perfectly, revs fine, drives fine, the power is normal, does not blow any kind of smoke, the noise gets quieter as I go faster but louder again as I slow down. (I have not been brave enough to drive it more than around the block.) I can't quite tell where the sound is coming from, but it seems to be coming more from the passenger-side of the engine compartment. What the heck is going on?

Following the advice of this thread:
http://www.fordfestiva.com/forums/sh...ad.php?t=18167

I am going to replace my plugs, wires, distributor cap and rotor (it is due anyway)... what else should I be looking for while I am tinkering?

[Amos]

I'm pretty sure I have the exact same thing.

[thirdman]

Well, I had a semi-emergency that I had to go to, so I dumped a pint of Marvel Mystery Oil in the engine and took off. The noise got quieter and quieter until after about 20 minutes it was gone completely. I drove it for a separate 20 minute trip a few hours later and it did not make any bad noises at all!

I wonder what it was...

Ah, well, ignorance is bliss, I guess.

[Tim]

I finally got around to it, and now it makes a very distinctive knocking/clattering noise that sounds just like a little diesel engine.

It starts perfectly, revs fine, drives fine, the power is normal, does not blow any kind of smoke, the noise gets quieter as I go faster but louder again as I slow down. (I have not been brave enough to drive it more than around the block.) I can't quite tell where the sound is coming from, but it seems to be coming more from the passenger-side of the engine compartment. What the heck is going on?

Where is the clattering coming from? Head or the block? Is it a loud knock or more of a quiet tap?

Worst case you could have a crank bearing go bad on you; most likely case is your valvetrain making the racket.

My '89 makes all sorts of terrible noises when it's cold, but that seems about normal for the higher mileage/abused Festivas.


-Tim

[FB71]

If it got better with MMO, it was most likely a collapsed lifter.

[thirdman]

If it got better with MMO, it was most likely a collapsed lifter.

What are the implications of that?

[blkfordsedan]

I agree with the collapsed valve lash adjuster (lifter). Especially if the engine sat for a while, the HLA's will bleed down or lose their prime. If the noise is gone then the lifter is back to normal and everything should be fine, but don't be surprised if it returns some time.
New lash adjusters are only a few bucks each and easy to replace when the time comes. Extended driving with a collapsed lifter can lead to permanent lifter and/or valve stem damage, but it's an easy fix.