I recently posted info on my 1995 C280 timing belt cover gasket leaking. It's a slow leak and was just supposedly
fixed by my mechanic. However, I think it still may be slightly leaking. I know that there are these 'Stop Leak' oil additives
out there. Is it worth trying one of these to stop this annoying leak or will it ruin my engine? I don't want to have to go back
to the mechanic and have them fix it again (and again) if this will solve the problem. Or am I just being obsessive and should just mop up the few drips of oil every couple of days (which I really don't want to do)?

 

To Add or Not to Add, that is the questions? Answer NO! Have it fixed, as these "sealing" additives don't work, at least I have never found one that did

 

Hi Crit1,

I agree with Wizard... DO NOT use stop leak.

Here's a thread from a guy with the same problem. -----> https://mercedesforum.com/m_21899/mpage_1/tm.htm#21904

I outlined one of the "most likey" causes of the leak. On that engine, the actual head gasket can leak as well.

If you want to get to the root cause of the leak yourself, you can purchase a leak detection kit (check your local autoparts store) for oil. (they have them for A/C and Coolant as well)

These kits consist of a dye and a "black light" type light that will illuminate the dye.
Put some in, go for a test ride, then scan accross the engine block with the "black light", if you don't see it at first just run it a bit more. This all depends upon the size of your leak.

Hope this helps

 

The only stop leak, that works is radiator stop leak and I prefer the $1.50 silver powder. Danger from it is, that if you use it too much, it will lower radiator efficiency.
The gaskets sealers works by softening old seals. It will stop small leak for some time, but some time later the seal will completely deteriorate.
So don't put it on the car, that you are going to keep.

 

A good emergency stop leak for a radiator is ground black pepper. It doesn't dissolve in water and it will congregate at a leak. It can be easily flushed out.

 

Good one Lugnut.
Why didn't you say it year ago?
On my trip to Mexico last summer, the bumps on the roads cost the fan shaft scratching the hole in my motorhome radiator.
You might guess >>> in Mexico radiator sealers are unknown.
What saved me there was local Crazy Glue.

 

Apparently I had two oil leaks. The major one was the timing cover seal which was fixed. The second leak (relatively minor but still drives you nuts), was the timing chain tensioner. There's an aluminum washer there that can sometimes leak. The mechanic cranked it down and I think I'm all set (he said hopefully). Another question on oil additives. What are people's philosophies on additives such as STP oil treatment or other oil additive clones that supposedly add extra lubrication to 'critical engine components?'

 

From what I remember STP is oil thickener, that will change viscosity, but will not do to much improvement.
Molybdenum is know for hundreds of years to penetrate the steel surface and lower the friction.
Lot of those "Slick50" additives have molybdenum in it.
Just don't believe all the "miracles" they list on the flayer.

 

Well, the saga continues. I brought my '95 C280 to another mechanic (whom I trust). The oil leak that was supposedly a timing chain tensioner (according to the dealer where I purchased the car) is really the head gasket. Can't wait to fight with the owner about this one.