Replacing Oil Filter Housing Gasket On OM617 Engine - PeachParts Mercedes-Benz Forum

Squiggle Dog · #1 06-26-2013, 06:41 PM

This article will show you how to replace the oil filter housing gasket on an OM617 engine (W116 300SD pictured). My engine is nearly leak-free, but it has been leaking quite a bit of oil from the oil filter housing. Tightening up the bolts didn't fix it, so I knew it was time to replace the gasket.

I assume the oil level is lower than the housing, and am not sure about oil levels in the cooler lines, but it was time for an oil change, anyway--and I didn't want to test it. I drained out the old oil.

Raising the oil tower lid helps the oil in the filter drain.

In order to loosen the oil cooler lines, a thin 24mm wrench is needed to hold the fittings from turning. You can get one of these cone wrenches from a bicycle shop for less than $10. A 27mm wrench is needed for the nuts on the oil cooler lines. If the lines are taking too much force to loosen and it's starting to round the nuts, you may have to cut a slot at the box end of the wrench so it will slip over the line and grip the nut. It may also be necessary to cut off the open end of the wrench to clear the vacuum lines. It was not necessary for me, though I did have to use a small adjustable wrench opened fully to turn off the nuts completely.

After the top line is loose, there are two sets of clamps (at least on a W116) that hold the lines. These should be loosened so that the lines can be moved out of the way.

Squiggle Dog · #2 06-26-2013, 06:42 PM

After the top line is disconnected, you should be able to access the one below it.

The open ends of the cooler lines should be covered with foil to prevent contaminants from getting inside. After the cooler lines are removed, there is an oil pressure line with a 17mm banjo bolt that needs to be removed as well. The later vehicles have a sensor instead of a pressure line.

At the lower rear of the housing is a 19mm banjo bolt that feeds oil to the turbocharger.

Getting out the five 6mm hex key mounting bolts is a challenge. I had to use a combination of a socket and a key by itself to access them. Be very sure the tool is seated into the head fully, because it would be very easy to strip out the inside of the head! Using a 6mm ratcheting wrench on a short section cut off of a key would make the job easier.

I removed the filter, wiped the oil out of the inside of the housing, then plugged the holes to keep contaminants out while I cleaned it.

Squiggle Dog · #3 06-26-2013, 06:43 PM

There are two rubber O-rings (015 997 94 48) at the bottom of the tube attached to the lid that tend to shrink and harden over the years, which can delay the time the oil pressure gauge starts reading.

The oil tower has a gasket that should be replaced while it's out. After scraping off the old one that was really glued on there, I sanded off all remnants with brake parts cleaner and 220 grit sandpaper. I like to sand in a motion parallel to the edges so it helps keep the oil from weeping.

I started cleaning the engine block and put on safety goggles to keep debris out of my eyes. As I was working, I felt something crawl on my head and then saw it wiggling over my eye. I batted it away, and when I looked over, I saw a scorpion on its back trying to get up. I don't really like it when that happens.

It was a bark scorpion, the most poisonous one in North America, and my house is infested with them.

Anyway, I went back to work cleaning the gasket surface. Make extra sure nothing falls into the ports.

Squiggle Dog · #4 06-26-2013, 06:44 PM

Here is what a clean surface looks like. The oil filter housing should be the same way.

The aluminum looked aged and dull, so I used 400, 800, 1000, and then 1500 grit wet sandpaper on it, followed by polish.

I used a light coat of Reinzosoil compound on both sides of the gasket. It's really tricky to get the housing back on without messing up the gasket, but it must be done. I put one of the bolts through the housing and the gasket to align it as I threaded the bolt. I made sure all the bolts were started a few threads before tightening them. The factory says to tighten them to 25nm, but good luck getting a torque wrench in there. I torqued one of them and then tried to match the rest.

CHOO CHOO! Funnel in place and ready for oil.

Put in the oil of your choice. I use Amsoil 15W40 Heavy Duty Diesel & Marine Synthetic Motor Oil with high phosphorus and zinc content. Don't forget to tighten up the oil pan drain plug and put in a new filter!

Squiggle Dog · #5 06-26-2013, 06:44 PM

Here is the housing all polished up. So far there are no leaks from it, except the aluminum crush washers of the oil pressure line fitting really had to be cranked down upon tight to stop leaking. The EPC doesn't list the sealing washers for the oil pressure lines, but they are the aluminum ones that come in an oil filter kit that fit the oil pan drain plug.

mach4 · #6 06-26-2013, 06:57 PM

Very nice write up.

Wish my engine was as leak-free as yours.

Doktor Bert · #7 06-26-2013, 07:04 PM

If you are servicing the vehicle (no polish of housing involved) pop filter cap and allow to drain. Clean around housing with spray cleaner, remove the bolts, slide out the old gasket, slide in the new one (no sealant) and tighten.

I changed mine a couple of weeks ago. Took less than 20 minutes on the hoist...FWIW

Stevo · #8 06-26-2013, 07:32 PM

Your engine compartment is a thing of beauty, nice job.
I changed the filter housing gasket on my TD when we did the steering box, it was a piece of cake that way. I have no more oil leaks and also use Amsoil 15/W40, good stuff.

Diesel911 · #9 06-26-2013, 08:06 PM

On My 84 300D there was that issue of room for the Torque Wrench if had an Allen Socket on it. I solved the problem by replacing some of the Allen Head Bolts with a regular Hex head bolts.
I found a short 12 point socket for the replaced Hex Head Bolts and was able to squeeze a Beam Type Torque Wrench with the short Socket for those Bolts.

In another thread I read I Guy had a Mechanic do the Gasket Change and the Mechanic removed the Steering Box. If that is done you can torque the stock bolts.

Also My original Gasket was just Paper and was not glued on.

mach4 · #10 06-26-2013, 08:25 PM

Quote:

Originally Posted by Diesel911

Also My original Gasket was just Paper and was not glued on.

Don't waste your time with the paper gaskets. Get the real Mercedes "waffle gasket". You'll pay a bit more, but it won't leak!

The difference is obvious.

Guess which one seals better???

Doktor Bert · #11 06-26-2013, 09:04 PM

Quote:

Originally Posted by mach4

Don't waste your time with the paper gaskets. Get the real Mercedes "waffle gasket". You'll pay a bit more, but it won't leak!

The difference is obvious.

Guess which one seals better???

Use only the MBZ 'waffle' gasket and use no sealer...

kerry · #12 06-26-2013, 09:37 PM

I once bought an oil filter housing gasket from a dealer and it wasn't a waffle gasket.

Doktor Bert · #13 06-26-2013, 10:10 PM

Quote:

Originally Posted by kerry

I once bought an oil filter housing gasket from a dealer and it wasn't a waffle gasket.

Mine was inked with the Benz 'star' and part number. Obtained from MBZ of Laguna Nigel...FWIW

vstech · #14 06-26-2013, 10:34 PM

do you happen to have that part number?

SCORPIONS!!! acck! and I though fire ants were the worst to deal with working on these cars... I've even seen the occasional Black Widow... SCORPIONS!

where the heck do you live? I don't wanna go there and work on cars!

vstech · #15 06-26-2013, 10:37 PM

I used to live in Tucson for a while back in 79... never saw any scorpions there. except in bolo ties and belt buckles...