W126 motor ticking

Hi all,

My '91 560 SEL is ticking enough to bother me. It has 101K miles and has been well maintained. Seems to be louder from the front, on the driver's side.

Is it already time to replace the hydraulic lifters??

It isn't terribly loud, but I notice it. The Benz mechanic I took it to for it's last oil change said he didn't notice anything out of the ordinary.

I'm running Castrol 10w-30 now (temp ranges have been 0-35 Farh. since December, but spring is near!). Should I move to a heavier weight?

Thanks in advance for any input!

mine does the same thing started at 220k i live with it because i don't have the money took fix it. it is fine untill about 2k after the oil change and then starts up again. It doesn't affect me any the radio is always on so it doens't draw any attention

Yep, You got it. My 560sel did the same thing. Replaced hydralic Lifters, rocker arms and cam shaft on right side and sound went away. Not really hard to do either. And not to expensive about $550.00 FOR ALL THE PARTS. Have fun!

[geoellis]

W126,

You may first want to take a look at the exhaust manifold gaskets. A blown one will also cause a ticking sound.

Good Luck

[ymsin]

I'm curious - what kinda "ticking" sound is this??

I have this engine W126 that sounds like a train chucking when I step hard on the accelerator ... but ticking?

In anticipation ... :]

Hmmm...

It's not *that* loud, as in having to blast the stereo in order to drown out any sounds. The only thing I hear is that singing V8 at WOT.

It's valve train racket (click-click), more pronounced when it's @ sub-zero temps. Then again, sounds are always sharper when it's really cold.

I think a clack-clack would be a "bad" lifter. That would require immediate attention, IMHO.

Very true, could be an exhuast leak, esp. since it's seems more pronounced on the driver's side. When April rolls around, it'll be oil change time -- and I'll see if things quiet down a bit with a heavier weight and warmer temps.

Thanks for the input!

[JohninFla]

My 1989 560SEL ticking was a few worn rocker arms. This is evident only when you remove them, and you will see the worn area, where the camshaft rides. I replaced the rocker arms, changed the oil tubes and no noise! You will need the special tool to remove the rocker arms though. And, you get to pull some fuel injection supply hoses on the driver's side, to get the valve cover off. Buy some rocker arms, the oil tube kit, (1 per side), and set aside a saturday morning. You will want to look at the timing chain guides while you are poking around in there, and clean the valve covers if they need it. (Mine were nice and clean!)

Have fun!

you got it John! i was going hydraulic lifters? These are overhead cam engines. The ticking you hear if slight is normal, loud then you got a rocker issue. There are these shims that supposably take up the slack like a lifter would but they get worn and cause a light tick at idle, don't worry about it. kinda 560 only also, never heard a 420 tick but every 560 does.

[JohninFla]

Mercedes uses "hydraulic compensators" under the end of the rocker arms, pumped up with oil, to hold the rocker to the camshaft. Perhaps this is only in my SEL model, and different in Bigshot's SEC, (big sedan vs. performance car). I only know about mine, it is all I have worked on! There are shims that go under the rocker, and can be changed. You need a go-no-go gauge to set the proper clearance when doing so.
I disagree with ignoring the ticking. Here is why: This could be the start of the rocker damaging the cam lobe, and you will go the route of Benzman above, replacing all the components in the valve actuating train. This is fine if it goes well, BUT the bolts holding the cam bearings go into the block, and sometimes threads pull out with the bolts. VERY bad! Then you get to remove the head to helicoil it!! So I think I would look into the source of the ticking, and replace the rocker if needed. Also, good practice to replace the oil tube plastic parts as a PM.
My $.02, take it for what it is worth.....
Good luck!

Thanks for the input guys!

It sounds like an issue I should look into soon. It might be something I could do myself (if it's the rockers). Need to get the MB CD-ROM shop manual. Does that, by chance, have the procedure for rocker-arm replacement?

Will have to wait for warmer weather (another 2000 miles of driving). Hopefully it won't be too late -- that is, needing to replace the cams etc.

[JohninFla]

You can replace the rocker arms yourself, and the manual does have a procedure for this. You will need to purchase a tool to compress the valve spring while still on the head. It wraps around the cam and allows you to push on the valve spring to get the rocker arm out of there. You will rotate the engine around until the cylinder you are working on is at TDC, (valves shut). I see no way to cheat without buying the tool. I bought one, and it still was work to do it.

[Princess]

Maybe one of you can help me. My 1975 450 sl has a tick on the left side. I have replaced the cam, towers, cam oiler, rocker arms, lifters and valve stem caps. Still ticking. The engine also misses and I have replaced the cap, rotor, plugs and wires. My mechanic wants to pull the head because he thinks the valve guides are loose. The engine holds 160 pounds of pressure +/- 10. Before he takes my engine apart, what else can I check? Thanks!

[suginami]

I'd vote it's a leak from the exhaust manifold. I've had two cars develop this problem, where you could here a ticking noise coming from the engine, like a valve train noise.

In one car the manifold was cracked.

In another car (the Nissan), the studs on the manifold had broke, a common problem on all Nissan's with the 3.0 liter V6.

[Mike Murrell]

Question for Princess.

Is the mechanic who wants to pull the head the same one who did all of the other work you mentioned?

If so, find another mechanic. He should have considered loose guides when he had the cam out. If your engine is missing, loose guides would not be the first place I'd look.

[Princess]

It is the same shop, different mechanic. The first thing that was replaced were the cam and rocker arms. Still missing, still ticking so we replaced the lifters. Still missing, still ticking so he quit charging me and we replaced the valve stem seals/caps, cap, rotor, vacuum hoses. Still missing, still ticking. Now I am out of money so I can't take it somewhere else. Any more work that is done, I am going to be there to watch.