nylewis

I have a 99 C4. The engine was replaced and now has under 20K on it. A while ago I started to get a ticking sound. Very light and would go away. After a while, it got worse and worse to now almost constant but still goes a little lighter and almost goes away once in a while. It's coming from the pass side. It's directly relating to engine RPM. No check engine light and the car runs smooth and has power. Just damn annoying. I just had the lifters replaced out. The covers, cams, etc all looked fine. Leak down test came back good in all 3 cylinders. But I still have the sound. It really still sounds like a lifter. We were thinking of pulling the head next and checking to see if there is an abstruction causing less oil psi going to a lifter. I was thinking when the lifter spins around just right it gets pumped up. Other then that, I'm clueless. Anyone have any ideas? I hate to pull this thing apart again without really having someplace to look. Coils, plugs, MAF all new. Please, I need some ideas.

Here is a link to the sound.

/nylewis#p/a/u/0/d7MlyKBglGw

Barn996

Yipes, talk about ticking. I'm not not sure I'd be running it until properly diagnosed. GL

dresler

holy crap. You need Macster to listen to this.

redridge

What oil are you using? Thicker oil like 15w-50 should quiet her up.

Dharn55

Try to isolate where the noise is coming from. Use a stethoscope or you can use a long screwdriver held against the cheek bone near you ear. It is really hard to diagnose this from the video.

logray

+1 to Doug's advice, really hard to diagnose over a forum, a lot of guesses will be thrown your way...

Sounds similar to when I reinstalled my engine a few months ago, from startup it had a horrible tick in one bank. Turns out it was just a loose coil pack/connection or spark plug wasn't tight enough. After I removed and reinstalled all of the spark plugs and coil packs the noise vanished. Your tick sounds a little more pronounced than what I had.

Here's what mine sounded like. You can play yours and mine at the same time, they sound pretty similar to me.


Here's the thread:

https://rennlist.com/forums/996-foru...-bank-1-a.html

Down South

A loose spark plug/coil pack is what I was thinking as I listened to it. But I think you said they were all replaced. No change before or afterwards?

logray

Even if plugs/packs were replaced, as I had done with my engine, but there was a tick even though they were new... it is still worth removing and reinstalling them before you dive into the engine. Also check for exhaust leaks.

nylewis

I put in new coil packs with new plugs and then had the lifters replaced. So they were reinstalled twice with no help. Same thing with the exhaust, pulled a couple of times with no help but it really has more of a metallic sound to it. One of the coils arcing I could see making that noise but I cant see removing them twice and replacing them, having the same problem. I was thinking of pulling the wire to each cylinder one at a time to see if there is any change. Might be able to do that Saturday.

TomF

A common source of ticking is the evap purge valve, but this should be easy to isolate with a stethoscope.

logray

Or if you have Durametric you can deactivate the cylinders one by one safely in software.

Macster

To state the obvious the engine doesn't sound healthy.

It sounds to me like a Boxster engine I heard running on a lift with engine having what proved to be a bad IMS bearing.

Just to be safe, I'd advise you to not run the engine any more than you absolutely have to in order to identify the area from where the noise is coming from.

If you are not prepared to do the work yourself, which may involve removing the engine for a complete teardown -- then only the shop/tech that will be doing the work should run the engine. Of course you can arrange to be there.

If the noise is id'd as coming from inside the engine, then you need to know from where, as close to knowing as is possible.

Under a cam cover?

Or at the front or back of the block?

Where you pinpoint the noise as coming from determines what you do next.

If you want to do something that doesn't involve running the engine remove the oil filter housing and pour the oil and filter element out into a *clean* drain pan and see what you see.

What you see or don't see will be of some value, worth the cost of a filter element/o-ring and a half a quart of oil.

Sincerely,

Macster.

nylewis

I pulled the wire for each cylinder to see if it changed the ticking but it had no effect. I took a new video of the sound. I used a socket extention to try to isolate the sound and it really appears to be coming from the cylinder closest to the front of the car, pass side. It sounds metalic. I was told this cylinder is the most sensitive to oil psi for the lifters. Keep in mind the ticking started out as very light and only for a short time and over a thousand miles, to get to this point. And the car was still driven a few thousand after the noise began constant. With the leak down test coming back good and new lifters and coils put in, I'm stunned I still have the problem.

trendy996

If any part of the timing chain is hydrologic id look there as it sounds like a bad timing chain tensionor

Macster

Did you note the engine reacting any differently to each plug wire disconnect?

If there is a weak cylinder disabling it will often result in the engine reacting less -- loosing less rpms -- because this cylinder being weak to begin with it contributing less. If this contribution gets too low (or too high) the DME will log a misfire error code and turn on the check engine light.

Did you remove the oil filter housing and examine the oil and filter for anything?

That the engine still exhibits the noise/symptom after the leak down test came back ok and with new lifters/coils suggests -- to state the obvious -- the cause of the noise/symptom was not the coils or lifters and apparently the engine's compression is still good. That you have not seen any CEL with misfire codes suggests the engine's still relatively healthy, probably.

I'm always concerned about an engine making internal noises and continuing to run the engine and perform a self-diagnosis.

A couple of things. Be sure (and I mean be sure) the noise is not an exhaust leak, or a loose plug.

Before you replaced the lifters did you carefully inspect the cams to look for a bad lobe?

Did you check all valve springs for any breakage?

Did you replace all lifters (intake/exhaust)? Did you check each lifter for proper operation before installing it? Manually working the lifter in a container of oil to ensure the lifter fills with oil and that the zero-lash mechanism internal to the lifter body works is able to retain sufficient oil and pressure?

The camshaft cover is the upper half of the camshaft bearings. High pressure oil is fed to the camshaft bearings via grooves. The only thing that keeps this oil flowing to the grooves and lubricating the bearings is the quality of the seal job and the correctness of the camshaft cover installation that was done when the camshaft cover was reinstalled.

If this was botched then there can be a leak of this oil and one (or more) camshaft bearings is not being lubricated properly. This is an internal oil leak that can affect system wide oil pressure which can result in one or more lifters receiving less oil pressure than it would otherwise. As a result, the lifter will be noisy and likely wear faster too, along with its camshaft lobe. These are lubricated via splash from the oil that comes from around the lifter body and its fit in the head lifter bore.

However, if the noise is present from a cold start this makes the above explanation less likely.

Unless you find an external explanation for the noise I think you're going to remove the camshaft cover and make sure everything is ok.

I do not think you'll have to replace the lifters again, but you should remove each one -- remembering where it came from so it can go back in the same hole and work against the same camshaft lobe -- and check each one to ensure it will pump up and hold pressure for a reasonable amount of time. You have 12 lifters on each side and chances are most are good (they all may be good) and from the behavior of the good ones you can spot the bad one, if there is a bad one.

Be sure you check to see how much play there is with each lifter in its respective lifter bore. A loose fitting lifter will result in the lifter receiving less oil than the others. Noisy operation (or worse) will be the result.

At the same time you can carefully inspect each camshaft lobe and valve spring.

Be sure the camshaft is positioned properly in the axial direction too. I see holes in the each camshaft's end bearing diameters. These holes must line up with the grooves that are present in the bearings that are in the aluminum of the head/camshaft assembly. If they are not lined up properly this might affect oil flow at the top end of the engine.

Really, you are faced with a process of elimination possible causes some of which I'm afraid will involve a partial teardown of the engine, at least the removal of the camshaft cover on the noisy side of the engine.

Sincerely,

Macster.