Air blowing from oil filler cap???
Discussion
Posting for a friend, any help/explanation most welcome:
"Mitsubishi Shogun, 3.2 Di-D, 94500miles....
When you take the oil filler cap off there is a lot of air blowing out, the breather pipe is clear and it has not lost performance and it's not burning oil. There is no water getting into the oil but the sump seal is leaking and the one above, drips about egg cup of oil on drive every week. Why is there air blowing out?"
"Mitsubishi Shogun, 3.2 Di-D, 94500miles....
When you take the oil filler cap off there is a lot of air blowing out, the breather pipe is clear and it has not lost performance and it's not burning oil. There is no water getting into the oil but the sump seal is leaking and the one above, drips about egg cup of oil on drive every week. Why is there air blowing out?"
Mario149 said:
Posting for a friend, any help/explanation most welcome:
"Mitsubishi Shogun, 3.2 Di-D, 94500miles....
When you take the oil filler cap off there is a lot of air blowing out, the breather pipe is clear and it has not lost performance and it's not burning oil. There is no water getting into the oil but the sump seal is leaking and the one above, drips about egg cup of oil on drive every week. Why is there air blowing out?"
Perfectly normal as long as it isnt excessive. But as you seem to say the engine runs find in every respect...it's probably normal."Mitsubishi Shogun, 3.2 Di-D, 94500miles....
When you take the oil filler cap off there is a lot of air blowing out, the breather pipe is clear and it has not lost performance and it's not burning oil. There is no water getting into the oil but the sump seal is leaking and the one above, drips about egg cup of oil on drive every week. Why is there air blowing out?"
You just have an oil leak, fix it.
Each time a cylinder fires there is a lot of pressure inside that cylinder to drive the piston down on its power stroke. Inevitably some will get past the rings & its got to go somewhere! Each time a piston descends it will have a compressing effect on air/gases in the crankcase.
Usually this goes via the engine's breather system back into the intake. Removing the filler cap just allows it an easier exit.
As an engine wears more will get past the rings.
Blocked breathers cause the pressure to build up & can cause oil leaks from all sorts of interesting places - as I found with my RRC just after I bought it, the breather passages in the plenum were blocked solid. Worst case with the Rover V8 is that it can unseat the rear crank seal.
Usually this goes via the engine's breather system back into the intake. Removing the filler cap just allows it an easier exit.
As an engine wears more will get past the rings.
Blocked breathers cause the pressure to build up & can cause oil leaks from all sorts of interesting places - as I found with my RRC just after I bought it, the breather passages in the plenum were blocked solid. Worst case with the Rover V8 is that it can unseat the rear crank seal.
As above , but it might be worth taking the rubber breather hose off the air intake then run the engine there should be no more than a little escape of pressure if there is an obvious oilly Smokey mist then it would suggest engine wear to rings etc, caused by lack of servicing or been overheated or had injector problems
At some point ..
At some point ..
paintman said:
Each time a piston descends it will have a compressing effect on air/gases in the crankcase.
There is no compression in the crankcase, just windage and a little blowby. Think about it - for every piston which comes down there is another which is going up, so the air just transfers from one to the other.Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff