Originally Posted by top_prop

Howdy,

I'm new to this forum, though i've read some very useful posts here in the past as a guest. I bought my 240D in 2007. I've been taking care of it myself since then just using chiltons/haynes and a few threads here and there that I've googled etc.

I regularly change the pre-filter (with oil changes) and the secondary fuel filter every 6 months or so. I've adjusted the valves every six months or so too. I run Rottella synthetic motor oil.

The previous owner had the trans replaced in 2005 by a mechanic that specialized in mercedes down in Miami... I and just recently changed the trans fluid and filter (though I couldn't get the torque converter drain plug alligned with the access hole so it was only a partial drain... long story but i'll probably just do it in my driveway rather than on the base with their lift and get the plug out [I'm in the service and we have hobby shops with lifts and lots of rules]).

I run regular petro diesel. The prior owner ran a petro bio mix. But no WVO that I know of. When I first got the vehicle my prefilters would clog when the tank got low. I bio shocked a few tanks of dino diesel and reguarly changed the prefilter and eventually the secondary filter and haven't had much trouble since beyond what I'd consider normal particulate accumulation in the prefilter. (my other cars are GM 6.2 diesel trucks) I have run a tank or two treated with Slick 50 "Diesel Cleen" every 4 months or so.

Any ways I've noticed since I've owned the vehicle that when it was cold and asked for more than idle power would knock, so I got in the habit of letting it warm up... it never knocked at idle... until lately. Over the last 4 years or so I've noted that the water temp it would need to get inorder to apply more than idle power has crept up from 100, then 110, then 120 etc until now it has to be at 175 or if I put my foot into it, it will knock. Also the other day when the temp was 40 deg and I started it, it knocked until it warmed some then settled.... but I had to get the water temp up to 175 for it to drive without knocking....

I've parked the vehicle until I can get this figured out.

I'm thinking the IP timing has been slipping, but am looking for advice. I just ordered a drip test 'dripper' and am waiting for it to arrive. I'm looking for advice on fixing a knock that goes away as the engine warms.

Also I brought up the automatic trans issue as it seems the trans pulls a lot at idle in drive, and shutters in reverse... Especially if I apply the brake or stop the vehicle. Since I changed most of the fluid and filter it has improved but its not totally cured... It did seem to run better as the car warmed up after the change. I'll probably run the mix of old an new fluid a while and then do a proper drain of the Tq converter and trans with another filter change and see if it helps (perhaps varnish has built up in the trans?).

Looking forward to your insight. I really appreciate all the help I've gotten in the past from just reading posts here. I ran a search but didn't find much on knocking that went away with warming up.

Thanks!

Tom