602.962 New Lifters, Same Old Noise... - PeachParts Mercedes-Benz Forum

BenzEnthusiast · #1 03-10-2015, 04:56 AM

I recently replaced all 10 of the lifters or hydraulic valve clearance compensation elements (as the FSM refers to them) on my 1992 300D. They were getting to be very noisy at any engine speed or temperature. I had switched to Delo 400LE 5W-40 Full Synthetic and after 20,000 miles of that with no change and only more and more noise I was convinced that wasn't going to make a difference. Also, before switching to synthetic I ran a can of seafoam in the oil hoping to clear out any sludge that may have been causing the lifter noise.

So, I followed the FSM exactly to replace the lifters, even the part were you are to blow compressed air into a bolt hole on the back of the head to clear any possible blockage in the oil lines that feed the cam and the lifters. It went well and the engine sounded great immediately after the job.

I drove it gently for a while after the job to make sure all was well. Then, about a week and a couple hundred miles later some mild tapping started coming from the engine, but only if it had been running for over 30 minutes or so. I was concerned about the noise and was going to check it out as soon as I got home only to find that by the time I had gotten home the noise had disappeared. However, after a 1 hour drive to Sacramento, the noise returned with a vengeance. It sounded nearly as bad as it did before I replaced the lifters!

When the car is cold, the lifters make no noise and even when the car first reaches operating temperature they sound fine, but when it is driven for more than about 10 minutes, they start making noise. I'm frustrated, what did I do wrong?

Maxbumpo · #2 03-10-2015, 09:01 AM

You have done nothing wrong, the noise must be coming from somewhere else.

Have you used a mechanics stethoscope to check for the source?

Possible sources: Serpentine belt tension device, vacuum pump, alternator, injection pump, delivery valves, injectors.

I know of a case of seemingly undiagnosable noise that was solved when the two o-rings at the bottom of the oil filter stem were changed. The old o-rings were hard as rock and crumbled during removal.

Phillytwotank · #3 03-10-2015, 09:37 AM

I recently solved a similar noise situation on mine when i found the belt tension er to be a bit loose.

Zulfiqar · #4 03-10-2015, 10:09 AM

did you check the old lifters for bleed down before you took them out? usually done with a wooden hammer handle by pressing the lifters themselves. lifters that can press are bad.

NJ300sdl · #5 03-10-2015, 10:36 AM

Head gasket may have failed at the forward oil passage, bypassing pressurized oil into the timing chain cover.

BenzEnthusiast · #6 03-10-2015, 12:18 PM

Thank you for the quick replies. I am almost entirely sure it is the lifters, but I'm not dismissing another source of the noise. However, the noise is a distinctive hollow slap, but I will bust out the stethoscope as soon as I get over to my shop. I was even thinking that it could be an injector or two, but as the engine was making the noise last night, I cracked each injector hoping that it would seice, but all 5 resulted in the same noise just at a slightly lower speed.

The head gasket theory is interesting, but the same oil passages are utilized to lube the cam and lifters. Wouldn't I see significant damage to the cam bearings if oil wasn't reaching the lifters? I didn't see any damage to the cam or cam bearing when I had it apart. That is assuming that what is causing the lifters to collapse now is what also caused the previous ones to collapse.

I was able to easily compress 7 out of 10 of the previous lifters.

Also, my hot idle oil pressure has began to get jumpy which it never was before and the O-rings on the oil filter stem are new.

sixto · #7 03-10-2015, 03:32 PM

Quote:

Originally Posted by NJ300sdl

Head gasket may have failed at the forward oil passage, bypassing pressurized oil into the timing chain cover.

x2 particularly if oil pressure gauge is jumpy.

Sixto
MB-less

Maxbumpo · #8 03-10-2015, 04:31 PM

Quote:

Originally Posted by sixto

x2 particularly if oil pressure gauge is jumpy.

Yes, sorry to say. The good news is the a new head gasket is a lot less than new lifters! The bad news is that the work required is far greater...

The ruptured oil passage is dumping some pressure into the timing chain cavity, most likely, but there is enough pressure to dribble onto the tops of the lifters / camshaft to prevent visible damage. There simply is not enough pressure to fully inflate the lifters.

I hope you have saved all the old lifters, as they are probably fine.

Maxbumpo · #9 03-10-2015, 04:38 PM

When I installed the new (used) head on my OM603, I went to great lengths to flush the oil passages in the head prior to installing the camshaft and lifters.

Basically, I suspended the cam gear wheel with chain in the right spot, tied down the stop lever on the injection pump, and cranked the engine over with the starter. As oil began to flow, I would let it run for 20-30 seconds, and then plug that hole to force the oil to the next hole. The oil bore for the first camshaft bearing pressurized and bled oil first, followed by the lifter oil bores for cylinder one. I stuffed a rag around the first camshaft bearing (be carefull that it doesn't get caught in the timing chain!!), and then installed the lifters for cylinder one. Next oil flowed from camshaft bearing two, let flow for a while and then plug with finger to force oil to flow from bores for lifters for cylinder two, etc.

I'm wondering if a similar procedure with your _possibly_ ruptured head gasket at oil passage would reveal that the oil pressure is too low? Never mind, would be a real pain in the butt to test that way.

You may be able to see oil flow down into the timing chain cavity with the valve cover off?

BenzEnthusiast · #10 03-10-2015, 05:42 PM

Well damn... Anyone else have a head gasket failure similar to this scenario?

Also, would I be correct to assume that the hole in the head gasket that possibly failed is the one I have the red arrow pointing at?

BenzEnthusiast · #11 08-06-2015, 07:25 PM

I've had the car parked until I could find the time to tackle removing the head and I was very glad to see an obvious failure of the head gasket once I got the head off. The whole job went surprisingly smoothly, hopefully it goes back together just as smoothly. Thanks again for all your help.

leathermang · #12 08-06-2015, 07:54 PM

At the time you did the lifters....and the noise stopped for a while... did you do anything else at that same time ?
If not , I agree you are still looking at the lifters.....

winmutt · #13 08-06-2015, 08:33 PM

Injectors poptested? Injection time right? Did you actually test the lifters?

BenzEnthusiast · #14 08-07-2015, 05:53 AM

When I replaced the lifters, I pulled the old ones out, checked the oil tubes that feed the cam and lifters for blockages, then installed the new lifters that had been soaking in oil for several days.

The lifters were quiet for several days until I drove the car on an hour long trip. Then they started making noise again. I let the car cool down and then started it to see if the noise was still present. It was, but only for a moment and then it was gone. I think that when the oil got hot and thin, the oil pressure to the cylinder head dropped significantly, causing the tapping lifters. Then, when I started the car cold, they pumped back up with oil since the oil was thicker and less of it was able to leak past the head gasket.

Another irregularity that I noticed was that the oil pressure was very jumpy at idle when the car was warm. I think this was a sign that compression from cylinder 1 was entering the oil passage in the head.

I drove the car several times after replacing the lifters before deciding to park it. The pattern was always the same. Cold, quiet, warm, tons of racket. Also, just before the lifters got really noisy (before I replaced the lifters), I had gotten the turbo working correctly. That may have helped the head gasket along... oh well.

And the injectors have not been tested.

I'll report the results when the car is back on the road. Thanks again.

BenzEnthusiast · #15 10-24-2015, 03:08 PM

Finally finished getting everything wrapped up on the car and have been driving it for about two days at this point and everything seems great. No weird oil pressure fluctuations and no concerning noises.

The job went smoothly other than some hold ups with parts or waiting for tools to repair the threads for the tensioner.

So, hopefully it holds together this time. It's apparent that the job had been done before I owned the car since it had the revised head gasket already in place, but it still blew. Maybe they didn't torque the head down properly. Who knows...