Here's a basic checklist to follow..
BODY: Check rocker panels for rust, especially around jacking holes. Look in each front wheelwell and make sure that the upper stabilizer bar is secured to the firewall. If you see any rust in there, stay away by all means. Check bottoms of doors for rust and pull the carpet up and check floorpans for signs of rot. You might also want to look at the radiator support where the identification tag is riveted and make sure there aren't any odd looking weld "scars" (could mean the car was involved in an accident). It's also a good idea to check the points on the body where the front and rear bumper shocks mount up for serious rot.
ENGINE: Check for smooth starting by cranking engine IMMEDIATELY after the glow plug light extinguishes. A common trick is to wait 10 seconds or so after the light goes out to start the engine. This will result in easier and smoother starting. Check for any large oil leaks from the valve cover and check the gasket inbetween the oil filter housing and the block for leaks. Also check the oil cooler lines for leaks. Open up the coolant expansion tank cap and make sure there is no sign of oil in the coolant (signifying the need for a head gasket). If there is oil in there, you'll notice a white, milky substance in the coolant and probably all over the tank. Also check the auxiliary fan for free operation and check to insure that the radiator cooling fins are not rotted away and leaking. Check the condition of the brake fluid. Brown or dirty fluid should be changed immediately. Pull the engine oil dipstick and make sure the oil level is at or near the top indent on the dipstick. If it's low, the car is using (or leaking) a helluva lot of oil!
CHASSIS: Check the tires for uneven wear and make sure the brakes feel nice and firm. If possible, check for a lip at the edge of the rotor, which could mean they're due for replacement. Check exhaust for any leaks and make sure there is the correct downpipe coming off of the turbo. A late '85 could have a trap oxidizer, make sure it has been removed (it looks like a large cylindrical muffler). I would imagine it should have been done by now.
INTERIOR: Make sure all power/vacuum equipment works such as windows, locks and sunroof (if applicable). Check the automatic climate control THOROUGHLY for correct operation on both heat and air conditioning. On the test drive, make sure the tranny doesn't slip and check the fluid to make sure it's not brown and burnt smelling.
OVERALL: Just give the records and the maintenance book a thorough checkover. Records are very important with any Mercedes. Usually the maintenance books are long gone by now, but a caring owner will have ordered another book from Mercedes when the first one filled up and will have kept records of each service carried out. Check the paint, interior and chrome and if it all looks good, make your offer accordingly. $6,000 does sound a little high, just because of the mileage, but I'd say $5,000 would safely buy it. Good luck!
Precision Motorcars, Cincinnati, Ohio
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