Hi,

For the last few weeks I've had a knocking problem in my 82 240D. Whenever I hit mid throttle under a small amount of load, I'd get clatter. Idle was fine, wide open fine. I had this problem last year on my first tank of ULSD. I tried a lot of things and finally removing, disassembling and cleaning the injectors got rid of the clatter. BTW, I burn WVO off and on with a two tank system. Also, tried valve adjustment and pump timing to no avail.

A couple of months ago, it started again. I pulled the injectors and they were dirty. I cleaned them. Still clattered. I tried cleaning all the spooge from the intake. Still clattered. Tried B20 and the STP diesel cleaner you put in the tank. Still clattered. Cracked each injector and it seemed that the clatter was in all the cylinders.

Well, I bit the bullet and bought two cans of diesel purge after hearing all the hype about it here and at other places. I never thought much of snake oil but I was getting pretty desperate. I could just picture the hole forming in the crowns of the pistons. And it is hard to tell people how nice a W123 is when your car sounds like LaMachine.

Anyhow, it worked. During the purge it went away. I didn't have my hopes up because I figured that Diesel Purge must have some anti knock additives. But I've put about 20 miles on the car after the purge and it is still sounding good.

No, it didn't stop smoking when I gun it. No it isn't too much smoother. But YES the clatter at tip in is gone! Oh yeah, and that thing about changing filters because of all the "dirt" it frees was not true for me. I watched the returned fuel in the clear bottle and it never got dirty. Very clear in fact. Whatever it cleaned got burned or was dissolved.

That was some expensive juice. Anyone have any ideas what it cleaned? I thought the fuel was too burned to clean the prechambers...maybe ignorant here. My injectors were clean. All I can really think of is all that WVO is gumming up my IP. My car gets addicted to it in that I burn it and it runs well then when I switch back to ULSD it clatters. Having a dry spell of oil I've been running ULSD lately and had the problem.

The WVO has made a sticky mess out of my filter rig and jugs. Could this same stick be messing with the pump?

So at the risk of sounding like a snake oil idiot (the kind I used to think posted here) Diesel Purge worked for me!