christian-c4

Hello,
i have a problem with my 92`C4 (Automatic-Gear) It has a noise at idle and some RPM higher (about 1800) Here are videos:

Here is one without valve-cover: I`ve checked it with a stethoskop. It is from the exhaust-valve at piston 8. It`s loud when i put the Stethoskop on the stud of the exhaust rocker arm. The same at intake ist quietly.

At cold engine it takes about two or three minutes to start with this noise. (engine at idle)

This i`ve checked till now:
Flex plate is not cracked. The three bolts are tighten. The others to crankshaft i can`t see.
The converters are ok
valve lash is ok

The noise is slower than the valves move. Could it be from oil-pump?

Also it is to slow for a bearing problem?

Perhaps someone knows what it is from?

Regards from germany
Christian

christian-c4

Hello

Problem with the Videos. Hope it works now

Christian

Klyde

At 800 rpm idle speed the valves each open and close about three times a second. The clicking is slower than that. Check your belt for a tear or a stray cord slapping on its way around.

Kevova

There was a condition of fuel line hammering in 92 you could listen to fuel rail and see if it sounds like your noise. If so TSB 93-6C-111 describes fix. It does sound like something rotating, I would disable belt and see what happens with noise. If it goes away it is something on the front of the engine or the belt. If no change could be carbon on a piston. It would be worthwhile to check oil pressure and #8 spark plug also. Disconnecting converter and moving it away from flexplate would isolate engine, to be sure noise isn't being transmitted from something else. You would want to mark converter to flywheel first.

christian-c4

Hello.
Thank you for the answers.
Moved Converter and disable Belt. The noise is still there. It isn´t fuel line and Spark Plug from Number 8 is ok. The Oilpressure is in the Video Nr. 2. It seems ok.
Could it be a Lifter? Or a camshaft bearing?

Perhaps someone know this noise from his car?

Silver96ce

Almost sounds like a bad lifter tapping on the pushrod.

Kevova

I never watched a video of rocker arm action, but number 8 intake doesn't look right. Sometimes you can use a stout screwdriver and push arm down against push rod and lifter to detect weak lifter. The noise would deminish or go away. With the valve cover off noise sounds to me like once per revolution...many times a piston, carbon or debris on top of piston, worn rod bearing causing piston to contact with head. You could change oil, check waste oil with magnet and cut oil filter and see if metal is trapped in to. Decarboning is worthwhile to try relating to carbon build up.

christian-c4

Hello,

Bad news
Metall pices in oil pan. Some of them go through the oil pump. I only take a look at rod bearing No.8. It is damaged too.
Ok, winter comes and i can rebuild the engine.