ML320 Oil Leak

[360glass]

Good morning,

My ML320 has developed an oil leak. It seems to be coming from behind the harmonic balancer. Has anyone experienced this? The ML has 172k on the odo.

[Carson357]

those models had issues with the harmonic balancer failing and would move toward the engine and can wear a hole in the timing cover, it is possible this has happened and was repaired incorrectly (jb-weld etc) and has began leaking again. or maybe just the engine main seal has gone bad. how bad is the leak?

[360glass]

I have neved had issues with the harmonic balancer. That was the first thing I checked and it looks good. The leak only happens when the engine is running, I have had to put 1 qt already (low oil light on).

[arkie]

I was by a local independent shop in Memphis yesterday, and I was complaining about the same kind of oil leak on 98 ML320. I was buying parts (interior goodies, as I am putting it up for sale) and one of the shop guys heard me talking about the leak and he told me they have had to fix several of these that the timing cover started leaking. The gasket or seal material obviously deteriorates with age, and starts leaking when the engine is running and makes a mess underneath. I'm going to take a close look at mine, as I am going to detail the engine out good and see where exactly the leak is. It had just recently got a little worse, it used to be only a quart every 3K miles but has crept up a little lately and I noticed a little more oil in the driveway. I replaced the ML with a 2004 Dodge Durango with a Hemi and third-row seating. We bought the ML when we only had 2 kids, now that we have three the ML is a little cramped. Its been good, none of the major problems and we have only had a couple things over four years that weren't just wear/maintenance items (EGR valve and the updated sway bar mounts and hangers for the front).

[360glass]

Well, the leak seems to be coming from a place behind the watrer pump. Quite a lot now. The water pump was replaced about five months ago. Could it be something was messed up when the H2O pump was changed?

[Lee Wireless]

My wife's 98 ML320 had the same problem. It looked like it was coming from behind the waterpump but I'll bet anything that yours is leaking where mine was. Look at the pictures closely. It was hard to get a good picture but if you study both photos you will figure out the part that is leaking. It's a small cover with two star bolts and a hex in the middle.You will need the type of wrench pictured to remove the two bolts. The hex looking casting on the cover does NOT come off so do not try to unscrew it. Remove the two bolts and the the small cover comes off. Clean the old gasket off good, clean the mating surface on the engine and do what I did. Get a piece of flat cardboard (not corrugated) and make a new gasket unless of course you have some gasket material. Put some flexible gasket sealer on both sides of the gasket and reinstall the bolts. Don't over torgue. Just snug them up. I did this repair two years ago and it's still sealed perfectly. Hope this helps.

[360glass]

Good morning,

Unfortunately that is not where the leak is coming from. It does seenm to come from right behind the water pump, about 4 inches left from where Lee Wireless kindly offered as an option.

And just my luck, this past Friday the ML went into some weird engine mode and the engine only revs up to 2000 and the ML fastest speed was 12mph. What could have happened? Anyone?

Best,

Ric.

[360glass]

Fixed. I removed the water pump to see if I could find what was causing the leak. Turned out to be two loose bolts. I have attached picture showing location of one of the bolts. Bolts were tightened at least 1 full turn. Wondered how they got loose.

[benztech13]

It wouldn't hurt to put some black locktight 5900 on the threads of those bolts.