Will it need a rebuild - 2001 JDM STi
18 July 2008, 07:48 PM
#1
Scooby Regular
Thread Starter
iTrader: (46)
Join Date: Nov 2005
Location: Probably polishing it.Lol
Posts: 5,381
Likes: 0
Received 0 Likes
on
0 Posts
Will it need a rebuild - 2001 JDM STi
2001 JDM newage STI, 60k miles, modded to 340/340 (Andy F remap)
Within a couple of hours of buying the above car, an oil leak occurred which turned out to be the front crankshaft oil seal. This seal was replaced and car ran like a dream and very quick.
After around 40 miles of the seal being replaced, the leak developed again. The car was returned to the mechanic, who replaced the same oil seal. The explanation given for it going again, was that there could be excess pressure building up inside the engine causing the seal to blow. Engine breather pipes have been checked already.
Question
.................................................. .................................................. ....
What can cause this build up of pressure and how can we check if there is excess pressure?
Thanks
Within a couple of hours of buying the above car, an oil leak occurred which turned out to be the front crankshaft oil seal. This seal was replaced and car ran like a dream and very quick.
After around 40 miles of the seal being replaced, the leak developed again. The car was returned to the mechanic, who replaced the same oil seal. The explanation given for it going again, was that there could be excess pressure building up inside the engine causing the seal to blow. Engine breather pipes have been checked already.
Question
.................................................. .................................................. ....
What can cause this build up of pressure and how can we check if there is excess pressure?
Thanks
Last edited by bob r; 18 July 2008 at 07:51 PM.
18 July 2008, 08:35 PM
#3
Scooby Regular
Join Date: Jan 2007
Location: in the engine bay
Posts: 909
Likes: 0
Received 0 Likes
on
0 Posts
my front crank seal went, the one in the oil pump, but i drove mine for about 5 miles before i knew, and i had to rebuild due to bearings being dry, yours is a different problem if it blows a new seal, all the best, phil.
18 July 2008, 08:40 PM
#4
Scooby Regular
haven't you posted this thread before???
same answer as last time, in that it is quite likely to be the oil pump pressure relief valve jammed causing v.high oil pressure
IMO ring blow-by would not be enough to blow the crank oil out unless incorrectly fitted
alyn
same answer as last time, in that it is quite likely to be the oil pump pressure relief valve jammed causing v.high oil pressure
IMO ring blow-by would not be enough to blow the crank oil out unless incorrectly fitted
alyn
18 July 2008, 10:02 PM
#5
Scooby Regular
Thread Starter
iTrader: (46)
Join Date: Nov 2005
Location: Probably polishing it.Lol
Posts: 5,381
Likes: 0
Received 0 Likes
on
0 Posts
The fault you describe is certainly feasable. Thanks for your input. Is there a simple way to test this valve or is it a case of stripping off the cambelt cover and removing the oil pump.
18 July 2008, 11:50 PM
#6
Scooby Regular
Join Date: May 2007
Posts: 213
Likes: 0
Received 0 Likes
on
0 Posts
Are you seeing high oil pressure readings? i would say until the problem is corrected do not drive the car. Covers\Timing belt off to get the oil pump out and check its condition. I had some right fun getting the crankshaft pulley off 
Subaru special tool 
Subaru special tool
Trending Topics
19 July 2008, 12:01 AM
#8
Scooby Regular
Thread Starter
iTrader: (46)
Join Date: Nov 2005
Location: Probably polishing it.Lol
Posts: 5,381
Likes: 0
Received 0 Likes
on
0 Posts
When the oil filler cap is removed, there is quite a throb of air that can be felt coming from the filler neck. Is this right?
19 July 2008, 12:23 AM
#9
Scooby Regular
Join Date: May 2007
Posts: 213
Likes: 0
Received 0 Likes
on
0 Posts
It needs a gauge to be tested. Take it to a specialist that can diagnose the problem and take your next step from there. If your self sufficent then carry out some tests yourself. Good luck
23 July 2008, 04:06 PM
#10
Scooby Regular
Thread Starter
iTrader: (46)
Join Date: Nov 2005
Location: Probably polishing it.Lol
Posts: 5,381
Likes: 0
Received 0 Likes
on
0 Posts
Update
Compression Test and a Cylinder Leakdown test done showing no problems and engine actually running very healthy.
#stockcar
It is looking more like the oil pump pressure releif valve as you suggest.
Can this PRV be checked or is it crankcase off again to get to the pump?
#stockcar
It is looking more like the oil pump pressure releif valve as you suggest.
Can this PRV be checked or is it crankcase off again to get to the pump?
23 July 2008, 06:25 PM
#15
At least the Compression and Leak Down tests came back ok indicating that the pistons/rings/bores/head gaskets are in good order.
Its un-usual for the PRV in the pump to stick in the shut position and give excessive oil pressure - they normally stick in the "relief" position and the oil pressure drops to the point of starvation to the mains and then the big ends.
IMHO,i would remove the pump to check the back plate screws are tight as when they work loose,the oil leaking internally on the pump will tend to push the seal outwards.
While the pump is off,you can remove the PRV(10mm Allen Key) and check to see if it is jammed in the bore of the pump or if it is scored.
The OEM Subaru oil seals are cheap enough and you can make sure its fitted correctly with the pump off the engine.
Mick
Its un-usual for the PRV in the pump to stick in the shut position and give excessive oil pressure - they normally stick in the "relief" position and the oil pressure drops to the point of starvation to the mains and then the big ends.
IMHO,i would remove the pump to check the back plate screws are tight as when they work loose,the oil leaking internally on the pump will tend to push the seal outwards.
While the pump is off,you can remove the PRV(10mm Allen Key) and check to see if it is jammed in the bore of the pump or if it is scored.
The OEM Subaru oil seals are cheap enough and you can make sure its fitted correctly with the pump off the engine.
Mick
23 July 2008, 06:50 PM
#16
Scooby Regular
Thread Starter
iTrader: (46)
Join Date: Nov 2005
Location: Probably polishing it.Lol
Posts: 5,381
Likes: 0
Received 0 Likes
on
0 Posts
At least the Compression and Leak Down tests came back ok indicating that the pistons/rings/bores/head gaskets are in good order.
Its un-usual for the PRV in the pump to stick in the shut position and give excessive oil pressure - they normally stick in the "relief" position and the oil pressure drops to the point of starvation to the mains and then the big ends.
IMHO,i would remove the pump to check the back plate screws are tight as when they work loose,the oil leaking internally on the pump will tend to push the seal outwards.
While the pump is off,you can remove the PRV(10mm Allen Key) and check to see if it is jammed in the bore of the pump or if it is scored.
The OEM Subaru oil seals are cheap enough and you can make sure its fitted correctly with the pump off the engine.
Mick
Its un-usual for the PRV in the pump to stick in the shut position and give excessive oil pressure - they normally stick in the "relief" position and the oil pressure drops to the point of starvation to the mains and then the big ends.
IMHO,i would remove the pump to check the back plate screws are tight as when they work loose,the oil leaking internally on the pump will tend to push the seal outwards.
While the pump is off,you can remove the PRV(10mm Allen Key) and check to see if it is jammed in the bore of the pump or if it is scored.
The OEM Subaru oil seals are cheap enough and you can make sure its fitted correctly with the pump off the engine.
Mick
Forgot to say, the PCV valve was changed today also which could have been an issue?
Thread
Thread Starter
Forum
Replies
Last Post