Mercedes-Benz Forum banner

1 - 20 of 47 Posts

·
Registered
"NEW OWNER" of a 1991 SL 500 weekend toy. Hope I don't go broke maintaining it!
Joined
·
600 Posts
Discussion Starter #1
As some of you may have read - My car developed a tick recently.

It is one single, "tap tap tap" coming from the driver's side valve cover.

I had in to the mechanic today where it remains.

As you can see in my profile, I own a 1991 500Sl with low mileage (73k)

The goods news is: Mechanic says "Its not only very clean. But exceptionally clean" under the valve cover.

Bad new is: Mechanic says "I can not find what is causing he tick".

I have older metal/alloy cam oil lubes and he insists they do not blow like the later '93-'95 plastic ones did.

He is checking cam lobe/lifter clearance. And suggested an oil flush, run for 20 minutes - and replace oil.

He feels the next step (which is costy) could results in $1,000 to check each lifter and he might still not find the source of the tap.

Found no scarring at all, no lifter marks, and squeaky clean engine head that you can eat off.

SO now what? ANyone have any ideas? I could post a video with the sound if that helps anyone.
 

·
Registered
1991 500SL V8 NEOKEN modified T/B. 2000 F350 4x4 V10. 1995 SL500
Joined
·
201 Posts
How bad of a tap do you have. If your clearances check out you should be ok IF he checks it correctly. There are many parts in the heads that can cause this and most you shouldn't lose any sleep over. My engine has a very small tap to it, more like a little click that a tap and it's not the clicking thing mentioned in other post. It's coming from the valve covers. If it's just a very minor tap I wouldn't worry a lot about it. If it gets worst then that's another story, I mean post. I have the same year model as you but with many more miles. Let us know what your mech finds
 

·
Registered
1996 SL320
Joined
·
285 Posts
good eve, if the tick proves to be nothing,I currently use Mobil 1 15W-50 everything runs quiet and is properly lubricated.
 

·
Registered
Joined
·
4 Posts
Just an idea...

I too thought I had a lifter ticking, only to find out that it is a small air pump that is located on the driver side just behind the headlamp. I would like to replace it, but I don't know what it is called. Just an idea.

Casey Albert
 

·
Greek God of the R129
SL500-500SEL-190E
Joined
·
8,389 Posts
Frank,

Pull the lower oil pan and look for particles.
There lays the answer.....

Did you read my post.
Engine ticking.
It will help you.

That is why I advised to seek help.
Gaskets and looking was not going to cut it.
Your problem is crap getting in the tappets/lifters.

They are dirt traps.
Do not go for the surgery thing yet.

Removing the pan is something that you can handle, as long and you pay attention to the bolts.
They are different length and some of them hold line brackets, if not careful
you can damage the treads.

Gasket is only $6 cheap.... ;)
Do not use any sealer on it.

Regards,
aam.
 

·
Registered
"NEW OWNER" of a 1991 SL 500 weekend toy. Hope I don't go broke maintaining it!
Joined
·
600 Posts
Discussion Starter #6
good eve, if the tick proves to be nothing,I currently use Mobil 1 15W-50 everything runs quiet and is properly lubricated.
For my climate, Charlotte (Southeastern U.S.) the manual recommends 20/40 or 20/50 oil since I do not have to worry about cold winters but do have to worry about many weeks over 90 degrees in the summer.

Does the 10/50 make it more liquid and "wet" (thinner)?
 

·
Registered
"NEW OWNER" of a 1991 SL 500 weekend toy. Hope I don't go broke maintaining it!
Joined
·
600 Posts
Discussion Starter #7
Tap

How bad of a tap do you have. If your clearances check out you should be ok IF he checks it correctly. There are many parts in the heads that can cause this and most you shouldn't lose any sleep over. My engine has a very small tap to it, more like a little click that a tap and it's not the clicking thing mentioned in other post. It's coming from the valve covers. If it's just a very minor tap I wouldn't worry a lot about it. If it gets worst then that's another story, I mean post. I have the same year model as you but with many more miles. Let us know what your mech finds
As for "how bad" it sounds like a little guy in there with a hammer hitting up against the valve cover. Its embarassing. I had enough when I passed a woman the other day (looking cool with the top down) and she said "Engine don't sound too good!"

That's when I said "that does it" and brought it in to mechanic. I will wait to see what he finds after checking gaps/clearance between follower and cam shaft. Just probing for suggestions.

Next will be aam's advise and dropping the pan.
 

·
Premium Member
1999 SL500, 2009 E350S 4Matic, 1992 300CE (sold)
Joined
·
143 Posts
for a female to notice it, it must sound like a jackhammer!

(couldn't resist)
 

·
Registered
1997 SL500, 1948 Rover 75 P3, 1984 Citroen 2CV, 1953 BSA Bantam D1, 1966 Velosolex Moped
Joined
·
1,141 Posts
I too thought I had a lifter ticking, only to find out that it is a small air pump that is located on the driver side just behind the headlamp. I would like to replace it, but I don't know what it is called. Just an idea.

Casey Albert
Hi Casey,
I'm not 100% certain but I believe you are descibing the Exhaust Gas Recirculating valve or EGR valve. Mine ticks too (passenger side here of course), and as far as I'm aware it should tick without actually being intrusive inside the car. Mine is audible from in front of the car but it's not a big issue, I guess as long as your car passes emission tests, it's nothing to worry about.
Other members will probably (no, definately ;)) put me right, if I'm barking up the wrong tree.
Regards
Steve
 

·
Registered
"NEW OWNER" of a 1991 SL 500 weekend toy. Hope I don't go broke maintaining it!
Joined
·
600 Posts
Discussion Starter #11
Tick that won't Tack

How bad of a tap do you have. If your clearances check out you should be ok IF he checks it correctly. .... Let us know what your mech finds
Well I just picked it up after the Mech. had it for 2 days.

Lifted driver's side valve cover
Replaced all gaskets (one was leaking - but I already knew that)
Could not find any issue with cam oil tubes (I have the pre-'93 alloy-metal tubes and not the plastic ones).
No blown tube caps either since my version has no caps (as per mech.)
Checked lifter gaps/clearances against cam lobes - NO PROBLEMS

Mechanic said "engine was so clean you could store food in it" and "cam lobe clearance were not just good - they were PERFECT".

So while this is all good news - and tells me last owner took good care with oil changes - we are still at square one.

I told him about "friends" (here in this forum) suggestion to look at oil filter valve and canister condition. After fighting me on this - he did.

FOUND - several "O-rings" from sloppy oil filter changes that had collected at the bottom.

SUCTIONED OUT - oil to get down below the filter canister level, and had to hand pick out all the rubber peices of O rings sitting down there.

Apparently cheap oil change places did not know how to properly place O rings. (this is similar to the problem I read which Albert 'aam' had with his oil filter apparatus).

Then ran engine with Mystery oil 25 minutes, flushed out oil, and replaced with fresh oil and new filter (propertly inserted 0-ring).

AND the RESULT????
[Drum Roll Please]

---- absolutely NOTHING.
Still ticking!

I read aam's thread and will suck it up and drop oil pan on next free weekend.

Mechanic insists while annoying, there's nothing wrong with my engine and I can drive distances.

But to me a tick is a sign of oil starvation somewhere.
 

·
Greek God of the R129
SL500-500SEL-190E
Joined
·
8,389 Posts
Yes you can drive it.
Yes on the mystery not working.
No it is not normal to have the ticking, but you already know that.
I suspect that if you look up with a flashlight you will discover a broken left guide,
and pieces in the oil pump pick up tube.

The 0 rings ummm?
Keep on digging, if I did it so can you.

Regards,
aam.
 

·
Registered
1991 500SL V8 NEOKEN modified T/B. 2000 F350 4x4 V10. 1995 SL500
Joined
·
201 Posts
If our car has hydrolic lifters then one of them is bad. I'm not sure we have them since this car is new to me. But a bad lifter will hammer just like you descibe. When they aren't under a load like the engine not running you really can't tell if you have a bad one. Take the valve cover off with the engine running and put your finger on each one and you can pick out the bad one very quickly it will be slapping a bit more than the rest. You will only have to run it for a few minutes to see the bad guy.
 

·
Registered
1991 500SL (Japan) - 133K KMS
Joined
·
311 Posts
SUCTIONED OUT - oil to get down below the filter canister level, and had to hand pick out all the rubber peices of O rings sitting down there.
I believe aam removed the canister off the block. Did you do that or did you simply take the oil filter out and did an inspection from the top-down?

I have to remove the canister as well and clean it out at my next oil change, as I too have the dreaded ticking. Like you, my valves are beautifully clean and sparkling. You'll see a couple of pics I took in the main ticking thread.
 

·
Registered
1999 SL 500 SL-2
Joined
·
170 Posts
Does it also have a small missfire at the exhaust at idle, that seems to synch with the tappet?

If the tappets are good, it could be a sticking valve, which won't exactly follow the cam profile. Should notice an irregular sound at the tail pipe, a miss that aligns with the ticking. Being a 32 V engine, there lots of guides and valve stems !

Won't hurt to run recommended MMO along with the gas and take it on some long trips. MMO will remove gum off the valve stem, if an intake valve is sticking.
 

·
Registered
"NEW OWNER" of a 1991 SL 500 weekend toy. Hope I don't go broke maintaining it!
Joined
·
600 Posts
Discussion Starter #17
Does it also have a small missfire at the exhaust at idle, that seems to synch with the tappet?

If the tappets are good, it could be a sticking valve, which won't exactly follow the cam profile. Should notice an irregular sound at the tail pipe, a miss that aligns with the ticking. Being a 32 V engine, there lots of guides and valve stems !

Won't hurt to run recommended MMO along with the gas and take it on some long trips. MMO will remove gum off the valve stem, if an intake valve is sticking.
Thanks but no miss at all. I can rev the engine while parked and it sounds like a beast except for the annoying tap - tap - tap.

This weekend is out and so is next as I'm attending a classic car drive in Charlotte for Alzheimer's fund raising - but the next nice weekend I'll try Albert's oil pan drop. I read his entire thread and at least that will detect what fell down there.
 

·
Registered
"NEW OWNER" of a 1991 SL 500 weekend toy. Hope I don't go broke maintaining it!
Joined
·
600 Posts
Discussion Starter #18
Infra - just inspected looking down into the oil filter canister. The mechanic did this after i brought this up.
 

·
Registered
"NEW OWNER" of a 1991 SL 500 weekend toy. Hope I don't go broke maintaining it!
Joined
·
600 Posts
Discussion Starter #19
Does it also have a small missfire at the exhaust at idle, that seems to synch with the tappet?

If the tappets are good, it could be a sticking valve, which won't exactly follow the cam profile. Should notice an irregular sound at the tail pipe, a miss that aligns with the ticking. Being a 32 V engine, there lots of guides and valve stems !

Won't hurt to run recommended MMO along with the gas and take it on some long trips. MMO will remove gum off the valve stem, if an intake valve is sticking.
Sorry for sounding dumb:What's an "MMO"?
 

·
Registered
1991 500SL (Japan) - 133K KMS
Joined
·
311 Posts
Infra - just inspected looking down into the oil filter canister. The mechanic did this after i brought this up.
The fact that you had debris in the oil filter housing tells me it's probably a REALLY good idea to do what aam did and remove the oil filter housing off the block (apparently pretty easy) and inspect the oil valve (part name?).

Check this post out and you'll see the part I'm talking about.

I strongly feel I have the same issue, but I'll know for sure when I take it off and inspect it at my next oil change. And of course,... having all my answers told to me by removing the oil pan (as aam loves to say).

Remember, if you take off the oil pan or the filter housing, buy the gaskets: less than $5-6 bucks each.


MMO - Marvel Mystery Oil.
 
1 - 20 of 47 Posts
Top