I have a 1986 Mercedes 300 SDL that I have owned about 2 months. It has about 165K. In that time it has ran beautiful. In fact you would never even guess it is a diesel it ran so nice. Anyway I took it on a trip about 3/4 hour had to climb a steep hill. When I got to the top it had blown out some water and oil. It never heated up though!! I added water, I went to check the dipstick and the oil in there was bubling like mad and came shooting out??? What might be the cause of this?

The car never really blew smoke at all before (very minimal) not something that you would say look it smokes, I would say it was normal like nothing much... Not something you could really notice at all. Now when I step to the floor it blows bluish smoke. I had some an issue getting it started after this all happened but now I can start it and it runs as nice as before. It starts like boom fast... it's always amazed me how fast this thing starts. Idles smooth However, now it is blowing bluish smoke all the time and moreso when I step on it.

Would this be the result of an o-ring? It's wierd because it's not running rough just blowing smoke now...

I would appreciate some help on this...

 

There was oil specs on the back bumper.

I went and checked the coolent no oil in there, smells and looks green like coolant. Coolant level is right up No bubbles. Also started nicely like usual. Doesn't sound or run rough at all. No smoke but it's been sitting for approx. 3 hours so its probably cooled off. Also no smoke out tailpipe minimal black but when I pulled up the dipstick the oil was bubbling out. Smells normal out the tailpipe. There is NO milky-gray ring around the oil cap.

Took if for a drive and there is a bluish white smoke coming out. Seems only under load this comes about, like I said no smoke at idle or when it is parked and I rev it after the drive NO smoke when its back in the garage...

 

I agree with ForcedInduction you're leaking compression into the crankcase through the head gasket.

 

this is a diesel 6 cyl .... strangely it does not smoke while idling .... just under pressure moving ...

I am somewhat mechanically inclined I just dont want to pull it apart until I get a good guestimate of what may be wrong and if it's worth fixing ..... it starts better that any diesel i've ever owned and quiet and smooth .... it hardly ever smoked even under hard acceleration ..... no bubbles in water or greyish tinge under oil cap...as would normally be expected if head gasket was gone ?????

It never overheated ..... there is a lower rad hose that leaks a little I was planning to replace soon so was watching water and temp closely...didn't even get out of normal range let alone overheat imho ... After driving it home I doindn't have to add water to rad it was still full up.

When I stopped the car later ...... I noticed oil leaking on ground ( which I assumed was becuz it was bubbling out of the dipstick and dripping down )
When I started it, it started blowing bluish smoke .... I had a car that the head gasket went and I wouldn't characterize this as white smoke like that more blue and smells like oil...

I checked the oil level after a 40 mile drive home and it was still okay.

 

There are oil and water passages going through the head gasket to the head, if it blew out between the cylinder ring and an oil passage, you might not get any water in the oil. It isn't likely that the crankcase ventilation suddenly plugged up, so the logical conclusion is the head gasket leak causing the excessive pressure in the cranksase and blowing oil out the dipstick tube. Whle it is rare that a head gasket leak goes only to an oil passage it does happen.

 

There are lots of products on the market to fix a blown head gasket would any of these products like thermogasket fix this problem seeing that its the oil end or would it just gum it up and make it worse?

 

Thanks that's kinda what I figured it would gunk it up. Today I took it for a 10 mile round trip and it barely smoked at all.

It is messing with my mind! I revved it to 3000 when I got home and held it there for a few seconds and it blew some blackish smoke and puff of blue. Then nothing...

Fluid levels all good!!! I know they don't fix themselves I am just wondering what to do now.

I was wondering where is a good reliable place to buy mercedes parts. I know I can buy at napa but it's half the price online???

 

Hmm, that does sound interesting. Definitely got my curiosity...especially since mine is operating "wonderful" now also. Keep us posted on what is going on...I'm interested to see how things turn out.

 

UPDATE: I've been driving it now for awhile, it seems to be running fine except that it's leaking oil from somewhere, not a lot but enough to be annoying. It doesn't blow smoke just a bit when you step on it. I think I hear the turbo because when I step on it I hear a whizzing sound. I never heard that when I first got it. So is it working right to be like that or is it going?

Also I can take out the dipstick and oil doesn't come shooting out like before. What do you think about that?

In the meantime I bought a 1989 420 SEL exact same color and style the motor is gone but the car is pristine. The interior and shape of my SDL is average seats are worn and leather is hard and dry with minor cracks plus drivers is broken this one they look next to new so I figured I would take out the whole interior plus doors everything I can to make my SDL look like new. It seems such a shame this SEL is a beaut wonder which is tougher take motor from mine and put in the SEL or is that even possible or totally take out interior, doors, hood, trunk and anything else possible to make SDL look like new. Any ideas?