Mercedes: Oil consumption, engine oil cooler, rod bender

Question
I have a 1991 Mercedes 350SD with 140,000 miles.
The previous owner indicated it used about 1 quart of oil per 1,500 miles. He was using Shell Oil.
I receintly changed to Pennzoil High Milage.
The oil comsumption is now 1 quart per 800 miles.
Other than the oil change, do you know any other reason the oil consumption would change so suddenly?


Answer
The 350SD has a reputation as a rod bender and head buster.
Depending upon which head # it has:
#1. Cracked head.
#2. Head gasket bad.
#3. Bent rods.

If you are very lucky, it will be wrong type of oil, an oil pan or engine oil cooler hose leak.

FYI:
You should only run DIESEL rated oil.

Here is a thread that will educate you on possible issues:
http://www.mercedesshop.com/shopforum/showthread.php3?p=863923#post863923