Compression specs for a 240D
 

Recently I was about to puches a 240D but was unsucsessful becouse the sellers father did not authorize the sale. To put it in other word i was relly pissed off to hear this:o ........but i began looking around for another 240D. Well my luck improved i found one about 40 mins away for Dirt cheap:D. how ever im not sure what the condition is in. I have the acsess to a diesel compression tester but im not sure what the minimum compression is before it became no good........if some one could let me know what the specs are for nomal compresson i would be most apreceative. And if anyone had any suggestions on what to look for when doing a basic inspection i would aprecate it aswell :D thanks

The minimum compression reading for the 240D is 17 bar or 255 psi. Another thing you might want to check is when its running (assuming it runs) pull off the oil breather tube at the cam cover and see how much air/oil is being pushed out. This is a good indicator of the amount of blowby that the motor has. I personally wouldnt purchase a car if more than one cylinder was at the 17 bar minimum reading because that would signal to me that the motor was on its way out.

Good luck with the car!:D

Pretty much what 240Demon said...... I wouldn't be too nervous if readings were a little low as long as they were all about the same. It's also not going to tell you much (compression check) unless the valves are adjusted correctly. Blowby could be a good indicator unless the car has been sitting a long time, there will be a lot of blowby then.

We always pull the hose off the Valve cover and block it with your finger (inside a rag of course ) after all.. diesel oil and the fluids around any diesel engine are almost permenent stains. .....After pulling off the hose and plugging it .. see how long the engine will idle before it stalls out..Usually a good engine will Run for some time ..a bad engine will start shaking and missing after about 1 min. or so..........Just a quick (on site test) like if you are at an Auction or a car lot and You don,t have any testing equiptment with you.....( just a trick of the trade)

Last weekend I checked the compression in a 1982 300D that the owner had run low on oil and started, what I think, is a lower end bearing issue because of the "knock". The low compression number was 380 and the high was around 420. Good numbers and, in my opionion, getting a little long on the spread. If you have a big difference between the cylinder numbers it is not good either.

ok about that test where you plug the hole on the valve cover. theres no seals that can be damaged or anything and what in fact is that doing to the engine:)

I suspect you could possibly cause some seal issues but like he said - use it where you absolutely can't do anymore test.