Loud tapping noise when warm...

[ZmOz]

My '90 4.0 is getting quite loud. After it warms up, there is really loud tapping noise coming from the engine. Continues even at high speed...and doesn't ever stop until it's cold. I put some seafoam in the crankcase hoping that would help...nope. What do you think it is and what can I do about it? Valve? Lifter? Injector? Elves with hammers?

 

[mengleff]

i think that's pretty standard with older 4.0's...
my 90 has 140k on it, and i thought it needed a valve job before i read the manual. it approaches the valve clatter of a diesel. i asked about it here and have since talked about while bs'ing with mechanic friends, the noise seems to be pretty normal in 4.0's with higher mileage. i have heard that replacing your serpentine belt can help, although from what i've heard, the noise does not indicate anything that will cause a problem.
that's not to say your noise is the same as my noise, but if it sounds like the valvetrain, it probably is.

 

[ZmOz]

I replaced my belt (and alt/water pump) about 100 miles ago. Seems rather loud to me to be a "normal" noise...but then again I'm no expert. If it is the normal noise you speak of, is there anything I can do about it? My engine does seem to be running fine, but this really makes it sound like an old peice of crap.

 

[89xj]

other than the usual valve train rattle, it could be an exhaust leak at the exhaust manifold. sometimes the manifold will crack and when hot exhaust gas leaks it will make a ticking noise that will increase with rpms.

 

[Spudboy]

My '91 made a loud "tapping" noise when warm for about a month before it sent the #1 rod through the block. Get it checked out!

It's almost impossible to sort out what the problem is over the internet. One man's tap is another man's clunk is another man's bang. Could be a flat lifter, bad camshaft, push rod or rocker arm, worn timing chain/gears, piston slap, rod bearings, or ???.

Just so ya know, I don't habitually drive vehicles making odd noises - I knew the engine was shot when I bought the '91, had already lined up a replacement, and decided to drive it until it died - I got about 9500 miles on it before the blow-up.

 

[OT]

Mine makes a light sort of knock knock knock, sort of tap tap tap all the time. According to the people in other threads regarding thid problem. it's most likely piston slap. Mine's been doin it since I got it back in January. I have 174,000 miles on mine and am told it's just a high mileage thing. IMHO it's not really a problem, just a PITA little noise. However it's only my .02

 

[ZmOz]

Well, if it's something major internal that needs to be "checked out" I'll just drive the thing until it explodes. It was free...and I'm thinking of putting in a stroker within about 6 months. I just want to quiet it down...it's kinda embarrasing...I might as well be driving an '86 taurus...

 

[OT]

Just tell everyone that it's a diesel.