Oil Being Passed Through My Rear Main!

[adam2oh5 0]

hi

i apear to be loosing oil through my rear main and loosing oil pressure wen the engine warms up,i know the presure drops abit because obviosly the oil warms up but for the life of me i carnt think why im passing oil through the rear main(at high rpm 4k to 7 k) that i have replaced due to thinking it will solve this problem,i thought oh just a faulty seal!

 

i asume its either the crank vibrating, to much bottom end pressure somehow( blocked breather pipes) or faulty pump.

 

but i had the crank polished and new bearings, the breather pipes was all cleaned and flushed through, but the pump has got one of them higher oil pressure springs in but would it make that much difference?

 

i just need someone to pin point this out for me so i can forget about it and fit me new weber carb kit on!

 

PLEASE HELP!

 

adam

[welshpug 1,629]

rear main what?

[rescue dude 0]

Are you going by what the oe oil pressure gauge is telling you or do you have a mechanical gauge?

 

A few years ago my oil pressure did exactly the same using the oe gauge.

 

It turned out it was the sender unit.

[Cameron 16]

rear main what?

 

+1.

[adam2oh5 0]

+1.

 

 

rear main gearbox side, running on the end of the crank!

[adam2oh5 0]

Are you going by what the oe oil pressure gauge is telling you or do you have a mechanical gauge?

 

A few years ago my oil pressure did exactly the same using the oe gauge.

 

It turned out it was the sender unit.

 

yeah im getting a new one today but the main problem is the oil pushing through the seal matey, im hoping this isnt a rebuild

[Cameron 16]

You mean the crank seal? Talking about mains usually means bearings!

[rescue dude 0]

yeah im getting a new one today but the main problem is the oil pushing through the seal matey, im hoping this isnt a rebuild

 

 

An oil leak wont affect your oil pressure unless the level is way low.

Edited July 7, 2010 by rescue dude

[adam2oh5 0]

You mean the crank seal? Talking about mains usually means bearings!

 

haha okay the actually name for it is rear main crank oil seal, got any input?

Edited July 7, 2010 by adam2oh5

[woodsy 0]

Is it defo the crank seal or could it be the hockey sticks that slide into the mains cap

[adam2oh5 0]

Is it defo the crank seal or could it be the hockey sticks that slide into the mains cap

 

alright woodsy

 

wen i had it appart the little rubber hockey sticks looked alright, i was hoping it wasnt them cus it would have been a pain

 

but at the botton of the seal you could see alot more than oil sweat, where the seal sits there is a little recess where you push the seal upto.now before i pushed the seal all the way in so it left a lip witch is where i could tell it was coming from there,i was thinking that maybe i did that wrong and stopping oil surculate through the little hole on the cap that the hockey sticks are on so i pushed the seal right up to the face and no further but still hasnt cured it im fitting a standard pump spring friday as its only 72 p and wen i go into work on satday im going to ask them what they think about it as matt from roger clark motorsport is king !

 

cheers for the help though mate as it really is bogling me !

[welshpug 1,629]

you don't need to change the spring, its most likely the hockey stick seals or the crank oil seal.

[adam2oh5 0]

you don't need to change the spring, its most likely the hockey stick seals or the crank oil seal.

 

nah it aint mate i got a presure tester on it and its running 90 psi at 5500 rpm. no rubber seal can take that beating. the only oil pressure upgrade was that s*itty spring so its comin out,

 

nice try anyway dude

[welshpug 1,629]

90 psi is exactly what its supposed to be!!!

 

your crank seal is the same as used on the XU10 which the 6 bar (90 psi) spring comes from.

 

however, your crank seal has nowhere near 90 psi being exerted against it, I'd be surprised if it has even half a bar or less as its simply crank case gases that cause any pressure they see.

 

you're just making more work for yourself, sort whatever is causing the leak.

Edited July 7, 2010 by welshpug

[Tom Fenton 1,528]

The rubber crank seal does not see oil pressure. It does see crankcase pressure which is a very different thing. Check that your breathers are clear, pipes not kinked etc.

[adam2oh5 0]

90 psi is exactly what its supposed to be!!!

 

your crank seal is the same as used on the XU10 which the 6 bar (90 psi) spring comes from.

 

however, your crank seal has nowhere near 90 psi being exerted against it, I'd be surprised if it has even half a bar or less as its simply crank case gases that cause any pressure they see.

 

you're just making more work for yourself, sort whatever is causing the leak.

 

why you getting agro'd for? i said 90 psi at 5500 rpm and reads higher and higher till the 7000 rpm

[welshpug 1,629]

I'm not getting "aggro'd" you just don't seem to get it do you?

Edited July 7, 2010 by welshpug

[adam2oh5 0]

i do get it. if you think that 90 psi is a normal reading at 5500 rpm wen standard is 50 psi at 4000 rpm is normal than your wrong.stop being a little key board warrior and thinking you can solve a problem without looking at the car, excesive oil pressure like that is not good do you not understand?

[adam2oh5 0]

90 psi is exactly what its supposed to be!!!

 

your crank seal is the same as used on the XU10 which the 6 bar (90 psi) spring comes from.

 

however, your crank seal has nowhere near 90 psi being exerted against it, I'd be surprised if it has even half a bar or less as its simply crank case gases that cause any pressure they see.

 

you're just making more work for yourself, sort whatever is causing the leak.

 

you will get pressure from the 8 mm oil feed

[welshpug 1,629]

90 psi is the standard pressure for an XU10, with the very same seal you have there.

[GLPoomobile 958]

i do get it. if you think that 90 psi is a normal reading at 5500 rpm wen standard is 50 psi at 4000 rpm is normal than your wrong.stop being a little key board warrior and thinking you can solve a problem without looking at the car, excesive oil pressure like that is not good do you not understand?

 

The irony being that WP is one of THE most clued up members on this forum. He's like some sort of X-Men character, whose mutation is having a rather nerdy ability to recall just about any Peugeot service information you could possibly need, at the drop of a hat Whilst Wolverine is busy slashing away at the enemy, Welshpug is busy confusing them with his uncanny ability to recall obscure part numbers from Service Box!

 

But hey, you just crack on fella. No point trying to accept a bit of friendly advice if you know better.

[Tom Fenton 1,528]

you will get pressure from the 8 mm oil feed

Not really my friend. The pressure at the oil feed at the centre of the bearing is 90psi or whatever your gauge is reading at any moment in time. The pressure distribution across the width of the shell bearing goes from 90psi at the middle, down to crankcase pressure (less than 0.5 bar) at the edge. {This is actually a very simplified explanation as there is more to it than that, but any more indepth goes into University level tribology and isn't relevant here in any case}

 

So back to what I am saying. The oil at the edge of the shell bearing is at crankcase pressure, as it has flowed across the main shell and now exits through the 2 drillings in that main cap back to the sump. So the only pressure forcing oil past the main seal is crankcase pressure. As I said before, as long as your breathers are OK this should be 0.5 bar or less, which is perfectly within the working range of a nitrile lip seal.

 

Back to your oil pressure, as stated by someone else, the "yellow" spring from the XU10 motor is rated at a nominal 6 bar (~90psi) if I recall right. So anything up to 90psi is to be expected, as the pump cannot relieve below this level of pressure. However if the pressure does continue to climb above this with revs, this does indicate a problem. If this is the case, what I suspect my be the cause, is that your engine has a pattern part oil pump, not the original one. These are machined ever so slightly different, but it means that the standard spring in them in softer than the standard 205 GTI spring, and so fitting the yellow spring to these pumps gives an uncontrollable oil pressure rise as the relief does not relieve.

Having said all this; this is still not the cause of your oil leak. However you do need to address it if it really is climbing beyond 90psi.

[adam2oh5 0]

Not really my friend. The pressure at the oil feed at the centre of the bearing is 90psi or whatever your gauge is reading at any moment in time. The pressure distribution across the width of the shell bearing goes from 90psi at the middle, down to crankcase pressure (less than 0.5 bar) at the edge. {This is actually a very simplified explanation as there is more to it than that, but any more indepth goes into University level tribology and isn't relevant here in any case}

 

So back to what I am saying. The oil at the edge of the shell bearing is at crankcase pressure, as it has flowed across the main shell and now exits through the 2 drillings in that main cap back to the sump. So the only pressure forcing oil past the main seal is crankcase pressure. As I said before, as long as your breathers are OK this should be 0.5 bar or less, which is perfectly within the working range of a nitrile lip seal.

 

Back to your oil pressure, as stated by someone else, the "yellow" spring from the XU10 motor is rated at a nominal 6 bar (~90psi) if I recall right. So anything up to 90psi is to be expected, as the pump cannot relieve below this level of pressure. However if the pressure does continue to climb above this with revs, this does indicate a problem. If this is the case, what I suspect my be the cause, is that your engine has a pattern part oil pump, not the original one. These are machined ever so slightly different, but it means that the standard spring in them in softer than the standard 205 GTI spring, and so fitting the yellow spring to these pumps gives an uncontrollable oil pressure rise as the relief does not relieve.

Having said all this; this is still not the cause of your oil leak. However you do need to address it if it really is climbing beyond 90psi.

 

cheers tom, i do understand about the crankcase presure but how is the crank case presure pushing on the seal other than through that 8 mm hole? the pressure pushes way upto 110 psi at 6000 rpm, could it be that the oil is not flowing through the hole and backing up and causing it to blow, not saying 110 psi is going through that tiny hole that would be silly but too much for it to flow properly?

[mickie 3]

i dont know much but if the pressure is getting to 110psi, that amount of force isnt being pushed onto the seals, there is a gap between the bearings and the seal.. pressure doesnt really come into it..

 

you just need to replace your leaking seal