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So here's the deal guys.

I've got oil spraying out of my dipstick tube as well as pushing my dipstick out of the tube about 150mm each time.
so clearly im getting pressure in the crank case

but ive tried all i can think of now im out of options, so far ive:

-replaced the PCV valve with a new genuine unit from nissan.

-checked all breather hoses to make sure they weren't blocked.

-done a compression test to make sure i wasn't getting excessive blow by that was causing oil to spray out. (read 140psi across all cylinders)

now thats where ive hit a wall..... i cant think of anything else to check =\
any ideas?


appreciate any help...thanks.

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just went and checked the rubber is pretty hard around the seal but its still fitting pretty firm

surely though that shouldnt justify oil spraying out of the tube right??

well damn i hope thats not the case.......

im not getting any smoke blowing out the exhaust so thats not looking likely in my case but i might still look into that if i cant get it sorted otherwise

Doing a comp test is all good & well for an N/A application, BUT, what's to say your rings are not responding when boost pressure is applied? The only way to truly cancel out your rings would be to do a cylinder leak down test.

I build, run & tune LARGE turbocharged stationary engines. I've encountered this issue before. Customer complained about an oil leak. Discovered to my surprise when going from idle to load @ about +10''Hg (max is 30Hg/14.7psi)) crankcase pressure was going from -.5'' H2O to +25'' H2O & popping both dipsticks along with twin fountains of oil till the rings responded at about +15''Hg then everything would settle down. This particular engine had issues rejecting heat through its heat exchangers, its dump radiators were too small & subsequently had alot of high jacket water temp shutdowns.

Piston rings hate heating up & cooling down. if the temps are high enough, over time, they start to lose their tension & don't respond very well to pressure changes.

Pressurizing your crankcase to the point of popping the dipstick out can only come from one place. The only other thing I can suggest as 'for the time being' fix is to get a little bit of heat shrink (for wiring), place it over the rubber, heat it & refit your dipstick to stop it popping out. Then just hope you don't start blowing out other seals!

I was just going to suggest a leak down test. :yes:

140psi compression test result isn't brilliant, especially if that was after cranking for a while. Do you have a catch can fitted?


I got similar problem whereby if I park my car on a hill it burns oil out the tail pipe...

Valve stem seals?

Doing a comp test is all good & well for an N/A application, BUT, what's to say your rings are not responding when boost pressure is applied? The only way to truly cancel out your rings would be to do a cylinder leak down test.

I build, run & tune LARGE turbocharged stationary engines. I've encountered this issue before. Customer complained about an oil leak. Discovered to my surprise when going from idle to load @ about +10''Hg (max is 30Hg/14.7psi)) crankcase pressure was going from -.5'' H2O to +25'' H2O & popping both dipsticks along with twin fountains of oil till the rings responded at about +15''Hg then everything would settle down. This particular engine had issues rejecting heat through its heat exchangers, its dump radiators were too small & subsequently had alot of high jacket water temp shutdowns.

Piston rings hate heating up & cooling down. if the temps are high enough, over time, they start to lose their tension & don't respond very well to pressure changes.

Pressurizing your crankcase to the point of popping the dipstick out can only come from one place. The only other thing I can suggest as 'for the time being' fix is to get a little bit of heat shrink (for wiring), place it over the rubber, heat it & refit your dipstick to stop it popping out. Then just hope you don't start blowing out other seals!

some really good info there thanks man

probably an easy fix there with a bit of heat shrink, but im not looking for a cheap fix here id rather get it sorted properly

and like you said id likely start popping seals lol....read up on another forum some guy just clamped the tube with a pair of vice grips :mellow:

looks like i should defiantly go ahead with a leak down test then and see how shes looking

I was just going to suggest a leak down test. :yes:

140psi compression test result isn't brilliant, especially if that was after cranking for a while. Do you have a catch can fitted?

Valve stem seals?

nah mate no catch can....... would be curious to see if im getting anything blowing out through the breathers as well as the dipstick now that you mention it

defiantly worth doing then if you think it will help
being that the breathers run back to the intake though wouldn't that cause a vacuum in the lines from the pcv valve and through the breathers though??
hence its at negative pressure anyways?.... thats just a guess


haha well lets just say
I've got a heavier foot than brian o'connor.... pretty hard

Antz. U thinking a vented can?

yup..would have to be...you could just stick little filters a top your cam cover vents , but this will most likely spray oil everywhere...

anyway, to keep it simple.. if can is vented, block pcv...if can plumbed back to intake, retain pcv...

i could tell you not to drive it so hard but you would probably laugh at me :P

If u need bud I can make u a vented can. But me thinks ur problem will be increased buy the -5s u just bought. Enjoy.

haha i know right.... thats why im tying to nut this out before i chuck em on

shit timing how it kinda came up the day i paid for them :glare: ...... lol

you do some fabrication work do you?

i actually do think i "might" have a catch can off my old 33 in the garage somewhere

ill have to have a look ....but otherwise ill get back to you about that one :)

A catch can won't really help, you'll only be increasing the size of your crankcase a little. If a leakdown test fails to show where the problem is, then testing on a dyno to actually measure the crankcase pressure is what will be needed.

In my previous post I mentioned a water column measurement: +25" H2O. This is only about 1 PSI. It was an 18 litre 6 cylinder. It didn't take much pressure to lift the dipsticks. Just letting you know even a little pressure loss can do big things.

When you do a leakdown test, try to test in KPA not PSI.

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