Timing Chain Tensioner M103
 

I would like to replace my timing chain tensioner. How difficult will it be to screw back the cap? How tight is that spring?

Thanks.

why? if so you have to take the whole thing out as its a one way
type of piston if i remember correctly.

george

I am getting a tapping sound when I start cold. Goes away in about 3 seconds when the oil pressure goes on. I read a tech tip from the benzbin.com that states, "If you start your engine, after it sits all night, and you hear clatter which quickly subsides when you get oil pressure you probably are on borrowed time. Change the timing chain tensioner pronto regardless of how many miles on the engine."

Yes I understand it is a ratcheting type tensioner. I will install the new one set to the first detent. However, what I was wondering was how difficult will it be to push in the tensioner cap given the new spring?

A tapping/ticking sound for a few seconds after startup would, IMO, more likely indicate that a lifter is bleeding down. A loose timing chain is more likely to create a "rattling" sound.

The M103 timing/chain tensioner rarely needs work until well over 150K miles, and they should be checked whenever the head is removed for overhaul.

Duke

yea, rattle is a chain. tapping is a lifter.
don't know what you use but stick some mobil 1 15/50
in there and see what happens. might take a second change to
get rid of it completly if its a tappet noise. good stuff.
works on my customers.
if its a rattle then do chain and tensioner and look closely at the
guides.

george

The M103 has 166,000mi. I only use Mobil 1 grade of 15W50. Sound comes from very front of engine. Yesterday, the sound is not only on startup now. It is like an intermittent rattling. However, the tapping on startup does not happen anymore. I guess I should not run this engine until chain/tensioner/guides can be checked. Can it be driven to the mechanic or should I tow?

The intermittent rattling turned out to be a failed fan clutch bearing. Replaced fan clutch, bearing bracket, and pulley. 2 hrs. tech time.

For good measure, also replaced the timing chain tensioner at less than an hour tech time.

Problem solved; thanks to all for your suggestions.