R34 Oil Dipstick Pops Out Under Boost Test - Also Been Getting Low Oil Pressure Lately- Related?

[colossus]

As per title when I did a boost leak test about a month back the engine oil dipstick kept popping out (and when I undid the engine oil cap air would hiss out. From some research it appears the oil dipstick issue is not uncommon and is due to a worn seal (I couldnt find much info about the crankcase pressurising though except for the fact others have reported this too).

I can order a new disptick off Nissan. However Nissan say no R34 dipsticks in the country and I'm up for a 6 week wait...so firstly anyone know if an R33 dipstick is the same as these are in stock?

Secondly when I did my first oil change on the car about 4 months back I overfilled it due to conflicting info in the glovebox manual vs the owners manual on the net vs advice from SAU - so I drove it like that for a week or two without realising then had to drain a fair amount out (just under a litre).

The level is currently sitting right on the H mark now. It has been fine up to this point but in the last week I have noticed my oil pressure is sitting on about 6kg/m2 until its warmed up (say 5 minutes). It then drops to 2kg/m2 at idle after about 10 minutes of driving (this is good I'm told) and rises to around 4kg/m2 or more when accelerating (once again normal). However after about 30 minutes of driving it now drops to about 0.9kg/m2 at idle - I believe this is too low - could the lack of a good seal on the dipstick be the cause of this?? or you think it could be much more serious??

FYI - I tested compression not long ago and it was perfect across all cylinders. I'm using Castrol full synthetic oil 5w-30, its about 4 months old.

Edited July 3, 2008 by colossus

[madbung]

Compression in the sump...It can only get there one way.

[colossus]

Compression in the sump...It can only get there one way.

which is? don't hold me in suspense...

[madbung]

Was your compression test before the oil over fill debarcle?

Compession should be confined to the combustion chamber...compression in the sump generally means rings.

[colossus]

Was your compression test before the oil over fill debarcle?

Compession should be confined to the combustion chamber...compression in the sump generally means rings.

Its hard to remember but if I had to bet on it I would say the compression test was before the overfill debarcle.

Reading this site though and googling I've found heaps of threads were oil dipstick pops out when doing boost leak tests and the answers to those threads was a warn dipstick o-ring, so thought it was fairly normal...I've only become concerned since the pressure has been dropping at idle.

[Jmaac]

blocked pcv valve?

Edited July 4, 2008 by Jmaac

[DECIM8]

Have you got a catch can? Does it use the same hose sizes?

Secondly how many Km has your car done? Seems it may need more than 5w30 perhaps a 10w40 (stays thicker at higher temps which is where your 30 is thinning)

and what temps are your engine running at? Is your cooling system working 100%?

Just some thoughts... heres a tip dont take anyones advice on here. I read shit on here and pass it on, I almost always get flamed so obviously this whole forum is full of shit.

Edited July 4, 2008 by DECIM8

[madbung]

^^^ good advice, all most people can really do without seeing the car is spout random crap

[DECIM8]

LOL @ madbung's sig..

[Granthem]

I have had a similar oil pressure dropping at idle issue.

Sometimes my car will drop to 1.5 on the stocko gauge as compared to the usual 2 or just under at warm idle.

10w40 royal purple oil.

However i cant see how my car can magically lose oil pressure then find it again next time i drive/next time the revs drop back to idle. Ie once reved it goes up from 1.5ish on the gauge to where ever, then drop back to the same revs and once again return to 2

Im putting mine down to a faulty gauge/sender.

But obviously your drop is larger

[DECIM8]

Id say thats most likely a shit stock oil presure gauge all skylines come standard with them, seem to drop out randomly and sensors no longer correctly measure it or somthing.

Get a aftermarket.

[colossus]

Have you got a catch can? Does it use the same hose sizes?

Secondly how many Km has your car done? Seems it may need more than 5w30 perhaps a 10w40 (stays thicker at higher temps which is where your 30 is thinning)

and what temps are your engine running at? Is your cooling system working 100%?

Just some thoughts... heres a tip dont take anyones advice on here. I read shit on here and pass it on, I almost always get flamed so obviously this whole forum is full of shit.

No catch can, cars done right on 100,000kms.

Engine temps normal just under halfway, cooling system working fine.

Oil temp guage sits on 90 after warming up from 70.

What I dont get is what Granthem said above about how can pressure magically return next time you start the car. You see it sits at 2kg/m2 (at idle/light cruise) for the first 25minutes of a drive then without fail it now falls to 1kg/m2 on idle/light cruise and moves slightly up with revs. So it seems 25minutes is some sort of barrier - all I can think of is heat generation but as I said oil temp gauge dosnt move off 90 degrees.

Edited July 4, 2008 by colossus

[B0oStEr]

If your pcv valve is stuck it can allow boost pressure into the crankcase and blow your dipstick.

Pull it out and clean it with carby-clean.

[DECIM8]

PCV sounds like your problem. as above. obviously as youve got no catch can cant be that (might be an idea to install one)

Secondly start using a thicker oil a 10-40 at min your car is now in its tlc or die stage.. 100,000km needs thicker oil lets just say shes been around.

see how you go with that.

sp you may also want to replace the gauge stock is crap, get an aftermarket one.

Edited July 4, 2008 by DECIM8

[GTR-80Y]

Rings.