1990 300TE 4Matic with about 180,000 miles. The valves click until oil pressure comes up, but then go quiet for a period of time. Then one or more valves start to tick. It will come and go but is definitely getting worse. In the mornings I can hear them click when driving for about 2/10ths of a mile before stopping. They often click when warm and idling, but once again the clicking will come and go without a change in RPM or oil pressure.

Any ideas? Could it be something other than the valves?

Thanks.

Most likely the hydraulic lifters.. not a hard job. nor are they $$

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

What viscosity oil are you using?

__________________
1999 C280

I recently changed the oil to 15W-40W. In the beginning (a 1 1/2 yrs ago) the problem seemed to improve with a fresh oil change (regardless of viscosity), but its not the case anymore. Recently, I have tried thin oil for a week and then tried a heavier weight a week later but didn't notice a difference.

Thanks for the advice. I'll try replacing the lifters.

if you have not used mobil synthetic you need to use it. by the second oil change all noise should be gone.

I assume the hydraulic lifters have oil passages that are clogged preventing them from taking up the clearances between the rockers, cam and valves. Will the synthetic oil clean these passages?

Our local foreign car parts store sells Amsoil synthetic oil ($6.90 /qt). Any experience with this? Is it better, worse or the same as Mobil 1?

Thanks for the advice.

if it was me i would remove the valve cover and do a inspection of the rocker assy and see if any of the parts are broken or loose. those heads get soft from high heat and slow cooling and that causes a problem with the bolts not holding their torque.
larry perkins lou ky

yep, thats the problem. i assume the amsoil would do(no real experiance) but why when you can get mobil 1 15/50 almost anywhere? you should see some results rather quickly. but usually will take another oil change to get you cleared up. the mention of checking the rockers for loose bolts is a good one but usually the noise is consistantin that case.

george