Greetings. After viewing forum for last 6 months and learning a lot I need some advice. Purchased 91 350SD 2.5 years ago with 106K miles. Great car, I hope. Read about rod bender on forum. Started researching. From warranty records at Mercedes, I know in 1993 a rod broke with 38K miles. Can't find out if rebuilt or shortblock was installed at Florida dealer. My local KY dealer service man says he is confident what mercedes did was install new shortblock. I know a new engine was not install because engine number at top still matches original papers.
The second day I owned the car I drove it straight through 600 miles to visit family, 70-75 mph. Noticed oil consumption, 3/4 quart.
Last month with 147K miles (40K miles later) that same 600 mile trip (70-75 mph)resulted in one qt oil consumption. However, I notice it smokes more in last 6 months...blue is color. No oil leaks. I use Shell Rotella T 15W-40, change every 5K miles.
Driving locally I seem to go 800 miles on qt of oil.
Discussed issued with my local dealer he said at 1 qt consumption at 500 miles he recommends I bring it in...he says could be valves seals/ guides.
I read the forum about oil consumption test, compression tests, oil analysis tests. If rods are bending again, would the oil analysis pick up metals in oil? I guess I need some advice on whether any tests would give me piece of mind. In the meantime I drive it a lot on trips, 75mph, what a great ride! Mileage is always in 24-26 mpg range. Drives today like it did 2.5 years ago, seems to have great power, but this is my first diesel. I getting ready to drive on another 600 miles one-way trip, am I pushing my luck? Any advice is greatly appreciated!
JT

Whether the entire engine or the short block was replaced, the engine number will be different because the engine number is on the block. If the engine number matches... uhh... whatever document contains the original engine number, they rebuilt the engine (or just the lower half). I don't think they're into carving the original engine number on replacement blocks.

It's possible that the new engine number was entered in the MB system so a VMI shows the new engine number. Does anyone know if the EPC is updated as well?

Sixto
95 S420
87 300SDL

I am under the impression that the rods go bad kind of fast. If it has been burning the oil for the last 40k miles it might not be the rods. Maybe a turbo seal or the valve guides and seals.

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

When the rods bend they will eventually cause the cylinder wall to become out of round hence the oil burning. The oil use will increase gradually over a period of time to the point where it'll burn a quart every hundred or worse. Complete rebuild is the only solution.

Thank you. Some additional info...
The engine number I am refering to is the location identified in the original owners manual (top side of engine). This number matches the vehicle data card in the back of the original maintenance booklet.

I had an oil leak develop slowly over about 8 months, which I found to be coming from a corrugated vent hose leading from under the air filter area to the turbo. I tightened the clamp last month and leak quit. I hadn't thought much about it since as I thought I had read on forum that some accumulation of oil in this area was "normal". Is this a sign of turbo problems and would this account for large oil consumption? Thanks in advance for any advice.
JT

That's not a vent hose, that the air inlet to the turbo. If there's oil in that hose, it's caused by blow-by pushing oil from the engine through the hose from the valve cover to that corrugated hose. Some oil is normal. I don't know how much oil is abnormal. Consider something like -

http://www.angelfire.com/space/neon/catchcan.html

or -

http://srt4.thebatanesislands.com/mysrt4/gal_20bux_catch_can_060203.html

The angelfire site has a pop-up.

Sixto
95 S420
87 300SDL