Another leak thread question - PeachParts Mercedes-Benz Forum

sptt · #1 04-05-2011, 01:36 AM

Here we go. I replaced my Timing Cover Head Gasket, Valve Cover gasket, and now my car is leaking more from down below somewhere (not from the timing cover anymore) and burning on the exhaust (strong smell). It is not leaking from the back of the valve cover where the gasket has a u-shaped dip down. However, I also changed the oil days prior to doing all of this and used a different brand of oil (Penzoil) and am wondering if that would be a possible cause from reading all of the oil threads and different types that leak more and less. The only place I can see oil seeping from (barely) is from the oil cap which I recently replaced with a new one but doesn't seem to be sealing much better than the old one (put a new dipstick in as well just in case). Where else should I check? The wetness seems to start below the manifold backward. I also replaced the clutch fan bearing bracket and sealed that one bolt hole up good along with a new o-ring. No leakage coming from there either. Only thing left is the head gasket, right?

JohnM. · #2 04-05-2011, 01:44 AM

Is the leak near the back firewall (cyl 6)? If so, might be head gasket, that is where they typically leak.

sptt · #3 04-05-2011, 01:53 AM

It definitely is but also wet towards the front as well which is why I am a little baffled. I guess I need to clean it up good underneath to see where it is coming from. I read somwhere you can add something to the oil and it will show under a blue light where it is coming from...

JohnM. · #4 04-05-2011, 01:58 AM

Google for "uv oil dye". You need to clean the engine down extremely well so you can see where its coming from.

It is possible your front cover could still be leaking. The fan tends to "blow" oil down the side of the engine block, making it impossible to pinpoint the source of the leak.

sptt · #5 04-05-2011, 02:06 AM

I thought that might be the case, but it is dry and has stayed dry where it use to leak out of that timing cover. I did notice that when I had the valve cover off, there are some large holes in there, on the air filter side, that were clogged with gunk. I think there are only two of these holes on that side and nothing goes in them, bolts or valve cover fittings. Any idea what they are for? I will check on that dye. Thank you!

JohnM. · #6 04-05-2011, 02:13 AM

Back to basics....have you triple checked that the valve cover gasket is fully seated, and that it's sitting on the head straight? It can take a few tries sometimes, and the VC gasket sometimes likes to move around while you are trying to get the valve cover into place.

I think you are referring to the PCV vents? There is a short rubber hose that goes from the valve cover to the intake manifold, and then a larger hose that goes from the valve cover to the top of the air cleaner. Otherwise I don't know what you are referring to off the top of my head.

sptt · #7 04-05-2011, 02:25 AM

Timing cover...yes, it is on and u-shaped seal did not roll due to technique I used with a clear plastic piece that allowed me to adjust then slide out. Also replaced camshaft seal as well. Verified no leaks multiple times.

Valve Cover...These holes are next to the valve springs on the head, not on the cover itself. There are "like smaller" holes on the passenger side that are angled next to the valve springs (I figured these took the oil down and somehow recirculated it). Anyway, probably not important.