Adding to Aaron's check list as follows:
(1) MB will replace the trap oxdizer in 85 Calif model for free with an Oxidation Catalyst. The part number for the Catalyst is 126-490-34-14. The trap oxdizer and the Oxidation Catalyst look identical and you really have to check the p/n in order to tell if the car has the final recall or not. The new Catalyst is warrenty for 12 month. It is about $750 (P&L) to replace the Catalyst. Most of the info is based on the Recall Campaign #96-1121, dated 2/97.
(2) Some cars have problem with the speedometer. Check the trip and mileage readings to be sure they are moving during test drive. In some cars, the trip meter is not working but the main mileage meter is okay. Some cars have the digits working intermitently and you may not discover the problem during a test drive. About $100 to rebuild the speedometer.
(3) Check the oil gauge. It should be between 1.5 to 2 during hot idle but goes to over 3 when cold or normal driving.
(4) The temperature gauge should reach 80 to 85 degree in about 5 minutes of driving (dry, 75 degree outside). It should be between 80 to 85 for the remaining test drive.
(5) Open the engine oil filler cap during hot idling, if you see smoke shooting out, it is okay. But I prefer no smoke or little smoke. I saw one 617 engine with 250000 miles having no smoke out of the hole at all. The lowest mileage 617 engine I checked was 100,000 miles and it had some smoke. I have not seen a 603 engine (87, 300D) having smoke coming out of the filler hole. There is not too many 603 engine around anyway to make a conclusion.
(6) Check the electrical connectors on top of the brake fuild reservor. If it is disconnected, it is possibly because the brake warning light is on.
(7) When checking the windows and sun roof, be sure to open and close them all the way. Some times it has problem when it is fully open or closed. Sun roof is expensive to repair. Parts for Window problem can be from few dollars to 100 dollars.
(8) All doors, trunk lip, front hood, should be open or closed easily. All Door and trunk edges should align and fit. Otherwise, it may be an indication of accidents. If you find some 123 body cars having the front hood not level with the fenders, in most cases, it is okay.
(9) Check the antenna operation including the antenna switch. Many cars have a worn antenna rubber seal. The seal is very cheap.
(10) Check the rear-end for oil leak.
(11) Check the front windshield for crack or chips.
(12) Check hazard switch and then the turn signals. In some case, the turn signals are out of service after you play with the hazard switch. It is because the poor contacts inside the hazard switch. Check the remote mirror operation also. Hazard switch is about $20.
(13) Rock the fan by hand when the engine is not running. Small amount of play (fan clutch) is okay. Fan clutch is about $100.
(14) Check the A/C switches and heater operation. A/C may not work but at least you need the heater to work, especially the defrost switch. Look at the A/C hoses and connections for oily appearance that indicate leaking of freon.
(15) The non-metallic paint starts to crack on older cars and you cannot see the cracks unless you come very close to the surface.
(16) Check the sun visors. Many cars have broken covers or cracked case. The electricity for the sun visor lights is from the mounting clip which sometimes is broken. A sun visor is expensive, possibly $100. Mounting Clip is ~$5.
(17) Be sure the driver seat can be adjusted. Both front/back and up/down. It is adjustable to fit a very short person.
(18) Except the 85 California model, the air filter housing mounting screws or bracket are known to have problems. Try to move the air filter housing by hand to see if it moves. If it is loose, you can possibly hear it "clink" when you turn off the engine. The mounting screw set is about $10, bracket about $40.
(19) Check the coolent recovery tank for cracks. Tank is about $35
(20) Some cars have worn seat belt buckle, mostly driver seat. The buckle is about $30 for the driver side, $20 for the passenger. You may not notice that it is worn out the first time. Try to put the male insert into the buckle several times or compare the force required to push it into the buckle to the force required for the rear seat belt. Some cars may have broken male insert (smashed by the door).
Happy shopping and searching
[This message has been edited by be459 (edited 05-30-2000).]