Ticking and low oil pressure at start - Page 2 - PeachParts Mercedes-Benz Forum

Diesel911 · #16 10-23-2021, 11:27 AM

If the vacuum pump is not making the noise at least you don't need to worry about that.

Oil pressure. When was the last time the little O-rings at the end of that stem on the Oil Filter were changed?

I know it is a pain to recheck but if I was getting that ticking I would re-check the valve clearances. I was a diesel mechanic for 18 years but that did not stop me from occasionally getting a valve clearance wrong. I have also caught myself inadvertently picking up the wrong set of feeler gauges; exhaust when I was supposed to be adjusting the intake.

JHZR2 · #17 10-23-2021, 11:52 AM

Here is a video when warm, of the tapping sound. Towards the end when I put the camera by the ATF filler, it’s the most pronounced. Hard to tell where exactly it is coming from. I’m going to try the stick on the hard injector lines again later, but I’m not sure that’s it.

Please have a look and let me know your thoughts:

https://youtu.be/l_tYvtEdcX0

JHZR2 · #18 10-23-2021, 11:55 AM

Quote:

Originally Posted by Diesel911

If the vacuum pump is not making the noise at least you don't need to worry about that.

Oil pressure. When was the last time the little O-rings at the end of that stem on the Oil Filter were changed?

I know it is a pain to recheck but if I was getting that ticking I would re-check the valve clearances. I was a diesel mechanic for 18 years but that did not stop me from occasionally getting a valve clearance wrong. I have also caught myself inadvertently picking up the wrong set of feeler gauges; exhaust when I was supposed to be adjusting the intake.

That definitely has gone through my mind. Just need a free couple hours to do it. Was trying to address the obvious (injector) first.

Regarding the o rings, I typically change them but didn’t this time. Could be related. It now starts with the needle pegged, I think some of the initial issue may have been getting all the media fully saturated and flowing. The needle does drop after just a little driving. Less heating time than I’d expect, given a 7qt sump.

JHZR2 · #19 10-23-2021, 11:57 AM

Quote:

Originally Posted by 250 Coupe

A leaking exhaust manifold can make a ticking sound.

Switch from a solid stick to a piece of tubing to find it. Most any flexible tube will work although small stuff like vacuum hose can be a pain. 3/8” fuel hose or 5/8”-3/4” heater hose works very well.

Michael

So just touch it on things with the other end on my ear?

That’s better than a metal tip stethoscope?

JHZR2 · #20 10-23-2021, 12:12 PM

Actually, this video is better. Put the camera near the rear injector, next to no noise. Put it back by the at dipstick, hear it the strongest….

https://youtu.be/0jS6PFSPviM

JHZR2 · #21 10-23-2021, 06:29 PM

Update:

Went out and cracked the injectors one at a time. I wasn’t counting on much happening, the car starts perfectly, idles smooth, runs well at any speed, plenty of highway power.

Cracked each injector one by one, the engine ran markedly worse and slightly slower on each way. In a consistent way. Makes sense because I have had injectors redone by forum members not many miles ago. I wasn’t expecting a fuel issue.

I’m unfortunately thinking it’s either a rod knock or something underneath that is moving and hitting. It does change with rpms, and changes regardless of if changing rpms in neutral or when moving.

This would also be commensurate with why after just a few minutes of idling from cold, the needle comes off of being pegged. I get it that oil reassure drops as the engine heats, but it does so quickly on this car. A loose bearing allowing a lot of oil to flow would be a reasonable reason why pressure would drop sooner at cold idle than any other 616/617 I have or do own.

I sure hope it isn’t rod knock. If it is, I suspect it’s the rear most bearings, which cannot be done with the engine in the car, right??

barry12345 · #22 10-23-2021, 06:56 PM

Did the ticking change when you were dropping the cylinders? May be the video or perhaps my hearing. If the ticking did not stop I do not think it is a rod bearing.

Also to my limited experience it does not sound like a rod knock.

JHZR2 · #23 10-23-2021, 08:32 PM

Quote:

Originally Posted by barry12345

Did the ticking change when you were dropping the cylinders? May be the video or perhaps my hearing. If the ticking did not stop I do not think it is a rod bearing.

Also to my limited experience it does not sound like a rod knock.

Ticking didn’t stop. It slowed and sped up with the engine, as I cracked and closed the injector lines.

It doesn’t sound as “harsh” as rod knock I’ve listened to on YouTube. I don’t have experience with rod knock. It may be because the engine is running so well and smooth otherwise. If I wasn’t concerned about oil pressure dropping so soon, on a cold start, I’d be less concerned about rods.

It does sound like a tick or tap where two things touch each other. Rod… or something else. Thinking I need to idle it up in the air with the air cleaner off to see what I see….

250 Coupe · #24 10-24-2021, 12:53 PM

With the hose, one end in the ear, without closing the ear or pressing it too hard against your head. Pass the other end around the exhaust manifold without actually touching anything. If there is a leak, you will hear it loud and clear. It’s similar to cupping your hands around your ears to hear from a specific direction. It may even let you find a ticking lifter by scanning the valve cover.

Michael

JHZR2 · #25 10-24-2021, 05:13 PM

I put my car up on my kwik lift and listened from underneath. I used the mechanics stethoscope and my ear and nose to check things out. I think I might be wrong about an exhaust leak. I had the car in the garage, exhaust routed out, and I couldn’t get much under the hood, at least until the leaked diesel at the rear injector started to smoke. I listened all over. Probably need to do it 2-3 more times cold, but while the tick/tap was pronounced underneath, nothing, oil pan, block, etc. really was clearly it. The best spots to hear the noise I think were the injectors and head area.

Video from underneath, don’t mind the leaking oil…

https://youtu.be/9AocikawGMY

Idled it a while and the engine got warm. Diesel at the last injector (return hose leaking) started to smoke. Every injector sounds different with a stethoscope. I think 2, 4, and 5 are more pronounced ticking with the stethoscope. Harder to hear the sequential tapping at the IP, anyplace on the IP including where the hard lines connect.

When warmer it did seem harder to heat the tick or tap

https://youtu.be/hmQW3KSJino

So I think it may be more associated with the fuel system again.

I don’t have any idling videos from before November 2010. From posts on here and records, I think I installed rebuilds in July of 2010, either ones done by greazzer or c Sean watts, don’t remember. I do have another set from greazzer I think. So I’m guessing injector replacement is in order to see what changes?

For a quick and dirty test, can I reuse the heat shields?

Thoughts on the videos and sound??

Don’t want to spend a lot of time much ado about nothing. But if there’s an issue I want to keep on top of it.

Thanks!

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