I talked to mechanic today about a PPI for an 83 300d I am looking at. He said compression test does not need to be done because a leak test will give all the information needed. I am definitely a newbie, and don't know if this is right. Anyone care to help? What else should I insist on for PPI? He started oh the mounter mounts seem to always go on those, but I think I should be able to tell that from test drive. Thanks for anyone's effort on this issue.

Welcome to the group!

No need for a leakdown test if the compression is OK, but you can tell that, pretty much, by starting it cold. If it starts right up when the glow plug light goes out and doesn't make more than a little puff of white smoke, the compression is fine. If it starts hard, by all means get compression checked, and if low or variable between cylinders, do a leakdown check.

Engine and transmission mounts will be shot by this time.

Also check the brakes -- for some reason, owners of older MBs that don't want to keep the car feel compelled to cheat on rotors, and end up damaging the cailipers from running the rotors too thin (I've seen this on about six car so far, no exceptions......). Not a big deal, but a cost to deduct from the purchase price.

Check front suspension -- lower ball joints are hard to remove and replace. Track rod bearings ditto -- track rod to body bushings are easy.

Examine underbody for rust -- this can get expensive. Check the drains at the front fenders (under vent grille and at battery) for clogs and rust. Check trunk drains.

Transmission.

Things you can pretty much expect: Engine and transmission mounts, and engine shocks. Unless previously replaced, these are all shot.

Probably needs rear subframe bushings and differential mounts, too. Window seals front and rear are probably shot, need to be replaced to eliminate/prevent water leaks -- the water will rust the car out.

Door locks and ACC vac systems may be flaky -- this is almost always a vac leak, may be servos. Variable difficulty -- ACC servos are a pain.

Driver's seat springs are probably soft -- can be replaced easily, but not particularly cheap. Note that the driver's seat has a hieght adjustment, low seat may not be bad springs.

Good luck!

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Thank you Peter for taking the time to help me out. If you're interested in the test drive and my observations check new posting from me. Unless he's willing to come down in price I am not going to spend the money on a PPI. I am still on the lookout and will post what I find over here in Hawaii for anyone that cares to read about it untill, that is, you guys tell me to quit posting... ...Aloha