I'm not in the business, but I've sold my share of used cars. I agree with pretty much everything said, but especially the bolded part.Doubly so for Craigslist buyers.

Granted, I'm guilty of this to a degree. I try to buy more than I'm paying for, but the difference is that I leave the questions to a minimum and leave my expectations low. I'll take a chance when I feel good about a car, but I always inspect it myself, and have only once done a pre-purchase compression test.

Actually, that's worth mentioning. That was on my current winter car that I bought in 2013, a 1995 Subaru. My previous winter car, also a 1995 Subaru, had recurring compression issues which I believe were not uncommon. The car seemed like a decent buy from the ad, and I asked the seller if he'd mind it if I brought along my compression tester and did a compression test in his driveway as a condition of purchase.

He agreed, I ran the test myself, and I bought the car. I may or may not get another winter out of it, but for me, that test (once again, performed by me on the spot) sealed the deal for me.


Bottom line, I like bargains and make informed purchases when I can, but I'm fully cognizant of the fact that I'm still rolling the dice to a degree. It's a matter of managing risks vs expectations.

You could ask for a compression check done at your cost perhaps. Paid for up front. Hard to say what a sellers response would be though.

I as a seller would go along with this. Although in general I am easy to get along with. Also if it is junk I will not sell it anyways.

At the same time I would resist a complete stranger claiming they are interested in the car coming along and doing it themselves.

Generally though most of us go by the general sound of the engine and a check of the amount of blow by. Making sure it does not overheat and the oil pressure is normal. At least these cars have an oil pressure gauge instead of an idiot light. These cars are almost antique status now if not already. You have to normally expect some issues with them.

Doing a compression test on a 300D turbo requires specific tools and knowledge. Are you planning to do it yourself or hire someone? If the seller agrees, do the test. If not, don't blame him since there is some risk involved, things can go wrong like a glow plug electrode can break.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Doing a compression test on a gas car is more straight forward then a diesel. No heat shield to replace ( unless it is done from the GP hole ), no injector line to remove etc. it is a 15 minutes job compared to a 1+ hr job. Some V6 front wheel drive may take longer. if I were the seller, I would decline. If I were the buyer then I will look for tell tale signs and take my chances.

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Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.

Well aware. I didn't mean to suggest that the testing my Subaru and an OM616/OM617 were the same. I'd also decline.

In my case, I think the seller agreed to let me do it because I let him know I was serious about buying the car.