Blow by

[stcbenz83]

Oh, so with all these blow by questions, i figured i would add another one as well.

I did the blow by check to my car, when i opened the oil cap white smoke was comming out, it was not thick and it was intermitent but not to intermitent. defenetly was puffing some white smoke,


1My question is, what is to much blow by??
2what does to much blow by mean?
3from what i described, would u say my engine has to much "Blow By?"


thank you all for your answers

[TheDon]

did you do the oil cap dance test? loosen the cap dont remove it and see how much it dances... lil movement is good, some flopping around is marginal, if you have to have your hand above it so it doesnt fly away thats not good

another easy test is wait til it gets to about 30F outside and see if you can start it without a block heater, keep going to lower temps to see how low you can start it in, i think 20F without a block heater is good.. actually. i dont know if this test is for blowby.. but i would be assured if i could start my car in 20F

[stcbenz83]

did the dance test and the results arnt the best

I dont have to hold my hand on it, but it does move around quite a bit. it gets to the point were it almost toppels off but doesnt..


what do u make of this>??

[TheDon]

you've got blowby, my cap barely moves when the engine is cold and just rotates around a lil when the engine is hot.... how many miles are on your 240D

[stcbenz83]

well the engine is fully warmed up, to the point were it hurts to tuch the oil cap

ill try it when its cold

it has 247,000 on it


what does to much blow by mean?

[apache]

For what its worth, I performed the cap test on my 240 with marginal results. The cap danced vigorously. I guess my engine is worn out although it doesn't burn much oil and it always started on the first glow at 15F last winter. Maybe I should be looking for a new engine.

[stcbenz83]

same here, i dont have any smoke on start up that i can see, and the engine in the winter, except when my glowplug relay was out and i was using the block heater, when i fixed the GPRELAY, it started first try everytime, but last winter in illinois was mild.


my engine also burns no oil, the only time i have seen it burn oil is when i was doing 75-85 on the expressway trying to get to work, i noticed a slight drop in oil, but other than that, i dont see it burning oil

[bgkast]

If it starts fine, especially when cold I wouldn't worry about it.

[stcbenz83]

but what does it mean when u have to much blow by???

[diametricalbenz]

Originally Posted by stcbenz83

but what does it mean when u have to much blow by???

It means the engine is tired and the rings are worn. It has lost a fair amount of the sealing abilities in the cylinders therefore allowing oil and gas to escape during the compression and power stroke reducing overall power output.

[Hatterasguy]

Put the oil cap back on and ignore it. Unless you are going to rebuild the engine there is no point and looking into it further. If it runs and starts fine thats what matters.