Tapping issue that comes and goes

[tulsacarman]

I have top end tapping that I would want to say is valves. It will sometimes be there on cold startup but if I turn the key off and restart a few seconds later it is gone.

It also will come and go as I'm driving down the road (at differing sound levels) but if I turn the engine off and then let the forward motion of the car "push start" the engine, the noise is no longer there. The noise will often come back gradually again though, I can hear it starting again and the noise will increase to the point where it sounds bad.

I can be driving down the road and the noise will just stop. I can't say that it's a temp thing because it is a problem hot or cold. It can go awhile without doing it and then it can be there for awhile.

I had a mechanic tell me that it was the timing belt tensioner but I would think if it were the tensioner going in and out the belt would slip a tooth or I would really notice a difference in how well the engine operates. Even when it's making the noise it's still nice and responsive.

She's a '92, 5 speed car and the engine has pretty high miles on it.

[Team Lightning]

From your description, it sounds like an HLA,(hydraulic lash adjuster, which is kinda like a lifter in a V6-V8 motor) is losing it's prime or not pumping up completely. They are not hard to change.

[SiliconSoul]

^^^ What he said! (I took to long to post!)

I wouldn't worry much about it, you just have a leaky lifter that isn't pumping up fully. Mine has done this since the day I bought it. Warmer weather it seams to not do it, but
when it gets cooler out it often will do it on startup and go away within 5 minutes or less.

The only fix is to take the time and find out which lifter(s) is bad and replace it, but the general feeling on the issue is it doesn't overly affect the life of the engine.

[rmoltis]

You know I have a problem like this one^ .
I replaced all the lifters and the sound is still there.

Describe the sound.
Is it a high pitch tapping sound like a sewing machine. If so its probably lifters.

Or does it have a deeper tone/knock to it.
Because I'm still on the hunt to figure this one out.
I think I may have some bearings that need replacing.

[tulsacarman]

It's a tapping, top end.

So if it's a lifter how would turning the car off while driving and then letting the car push-restart itself cause the problem to stop, then gradually come back? Also, why would it come and go as I drive? When it stops as I am driving it's immediate, like flipping a switch.

I'd like to understand the mechanical reason behind what it's doing. I can accept the lifter reasoning, that's the first thing I thought.

[Team Lightning]

Could be a piece of debris in the HLA that's loosening up when you stop the motor. Then until it gets back into the right position and plugs it back up, its quiet. Isolate which one it is, then remove and clean them/it

[tulsacarman]

I'll get to it when I can and let you know what I discover. Thanks to everyone for their suggestions.