dropping temps and misc seals - PeachParts Mercedes-Benz Forum

d.delano · #1 12-06-2004, 04:52 PM

I have discovered an oil leak, there is some weepage around the oil pan gasket. I checked the oil level last night and realized that I suddenly burned/used 1/2 qt of oil while the car was parked for a week, after 3 ~400 mile trips and haulin' my family(7 persons) around DC Thanksgiving weekend without any usage whatsoever. Hmmm. So I looked under the car and sure enough. My question to the forum is this- do the misc seals contract when it gets cold, and would this phenomenon likely be the cause of my sudden leakage?
Thanks

dieseldiehard · #2 12-06-2004, 05:11 PM

cold weather caused the hdraulic seals in the rear shocls on one of my 300TD's to blow oil, I could still drive the car, but that is the only cold weather related oil leak I can say I have seen.
If anything, cold engine oil should seep more slowly than hot.
a sudden increase in oil loss should be pinpointed, if its leaking and not being burnt while driving. The oil cooler lines can be sources of major oil loss and should be the first place you look.
When looking for a leak it helps to clean the engine with a degreaser first so the leaks can be more easily spotted. There are some dyes available that use blacklight to detect and are the real sure way to leak check.
http://www.thetoolwarehouse.net/shop/UV-B483206.html

d.delano · #3 12-06-2004, 05:30 PM

I can pretty much see the weep trail, and I know and can see where its coming from(oil pan gasket), just curious why all of a sudden I'm leaking. Oil cooler lines will be done next year, not looking forward to it.

#4 02-25-2005, 08:29 PM

I assume that you mean the lower oil pan. The upper rarely leaks plus it is above the level of the oil when vehicle is parked.

If assumption is correct, lower pan gasket is very easy and quick to replace.

Hope this helps,

PatrickW · #5 02-25-2005, 10:07 PM

I start my 240D every so often during the winter, and let it warm up in my garage (I won't drive it in the snow/salt).

It tends to leak more when sitting there warming up than it does if I take it out and drive it on a nice day, and then park it back in my garage.

My thought is that old seals and gaskets contract when they are cold, and then when oil pressure goes up after the engine is started, the oil (and coolant as well) is allowed to leak.

When the engine warms up, the seals and gaskets get warm and expand, which stops the leaks.

- Patrick

d.delano · #6 02-25-2005, 11:11 PM

Thank you Larry, you're a gent and a great source of knowledge
PatrickW- you put more thought into it than I did, I learned something

This is an old thread, but I've since tightened the oil pan bolts a little, not too much, and the leakage has abated. For now

billrei · #7 02-25-2005, 11:24 PM

Quote:

Originally Posted by PatrickW

I start my 240D every so often during the winter, and let it warm up in my garage (I won't drive it in the snow/salt).

It tends to leak more when sitting there warming up than it does if I take it out and drive it on a nice day, and then park it back in my garage.

My thought is that old seals and gaskets contract when they are cold, and then when oil pressure goes up after the engine is started, the oil (and coolant as well) is allowed to leak.

When the engine warms up, the seals and gaskets get warm and expand, which stops the leaks.

- Patrick

Nice theory. But if he lost 1/2 Qt of oil there would be more than a little weeping. The gaskets are designed to seal over the temp range and pan gasket does not see the oil under pressure. Even the front and rear seals only see oil spray. Seems to me that kind of oil usage means it's being burned.

d.delano · #8 02-25-2005, 11:36 PM

Well I don't have any smoke, at least that I can see, in the daytime anyway. I do see some kinda grayish smoke at night in others' headlights but not much. I understand this is normal. I haven't seen the same oil consumption since I tightened the bolts.
I should point out that I recently got the car, in August, and changed the oil with Delvac 1300 Super. Changed it again after maybe 1500 miles and put Mobil 1 synthetic 15W40. I changed it yet again after another 2500 miles or so with Mobil 1 Truck and SUV. It's still on that oil, probably have about 1500 miles on it. So I don't know. It seems the engine just used some oil for whatever reason. Hope it's not burning it, compression's good and little stretch on the chain, no choo-choo out of the valve cover.

#9 02-26-2005, 09:54 AM

It is not uncommon to get a 616 or 617 engine that uses some or even a
BUNCH of oil. The good news is that diesels run on oil. It can be a big inconvenience, but unlike a gas engine oil consumption in a diesel causes no further harm to the engine.

In a gas engine, it will start fouling spark plugs and other problems, but with a diesel as long as you can carry enough oil to get where you're going it won't hurt anything.

This would not include some situation where oil is pouring into the combustion chambers causing the engine to run away with no engine speed control

In this case, it sounds like the engine may have sat under certain conditions that caused rings to stick. Running the engine and going through some thorough oil drains took care of it.

Have a great day,