OIL LEAK AFTER REBUILD NB

C-Gazer · Postby **C-Gazer** » Sun Jun 28, 2015 10:00 pm

Following a successful rebuild I have ended up with an oil leak between the oil pump housing, oil pan gasket and the sump. A few weeks ago I replaced the crankshaft seal hoping this was where the leak was however after the seal had been replaced the following morning oil was puddled between the sump and the oil pump. The car was car jacked up high at the front overnight so there was no way for the oil to have leaked from the crankshaft seal. I am considering trying to remove the oil pan gasket and filling the area with silicon. Have any forum members been successful in stopping leaks in this way? The alternative is to redo the sump.

JBT · Postby **JBT** » Sun Jun 28, 2015 10:17 pm

Are you sure it's not camshaft seals?

TrackAttack · Postby **TrackAttack** » Sun Jun 28, 2015 11:31 pm

What engine? Nb8a or b (svt or not). I've seen 2 common problems around oil pump\sump leaks. Early na6\8 oil pumps used a paper gasket. Nb's use silicone and an o-ring. Using the paper gasket on the nb pump will cause a leak. The other trap for young players is the crescent seals. If it has a MBSP it needs a different seal with cut-outs for the plate. These seals are not interchangeable.

The worst case here is the crank has a score in it where the oil seal runs, causing the leak. I have also seen a crank seal missing the internal spring, which will leak when running. It was a difficult one to pick but odious once the seal was removed. A few things to think about. Aftermarket seal kits can be incorrect in the model differences

davekmoore · Postby **davekmoore** » Mon Jun 29, 2015 8:19 am

TrackAttack wrote:Aftermarket seal kits can be incorrect in the model differences

All of the non-OEM (unknown to me) seals used on my rebuild leaked. The rear main bearing one hasn't been replaced yet. Oil from everywhere gets everywhere. Moral: Always use proper seals and the correct methods of fitting them.

C-Gazer · Postby **C-Gazer** » Mon Jun 29, 2015 6:08 pm

Thanks for the replies.
This is an NB8B engine with a new boundary oil pump fitted with silicon not a gasket. No leaks around cam seals.
I am 99% sure my leak is between the oil pump and the sump due to a puddle of oil forming in this area overnight when the front of the car was jacked up and the crankshaft pulley was off for no 2 seal replacement. There was no oil deposit around the crankshaft seal when the puddle appeared. During the sump installation I siliconed both oil pan gaskets in place on the engine before fitting the sump maybe the front gasket squeezed out of place.
Note. My little oil leak is nothing compared to what davekmoore has had to face.

TrackAttack · Postby **TrackAttack** » Tue Jun 30, 2015 10:40 am

Did the sump seal look like this? Most important the cut outs at the edge of the seal.

hks_kansei · Postby **hks_kansei** » Tue Jun 30, 2015 5:41 pm

SOmetimes overdoing the silicone can make matters worse.

Often if you need to silicone a gasket (and it's usually only cork or paper gaskets anyway) you just give them a light smear.

Rubber gaskets are usually fine as is, and may just need a few dabs of silicone near the corners (ie: Rocker cover)

If you really want to do the sump gasket with silicone, rather than just filling the gap with silicone (which will just peel out eventually) an old trick is to silicone, then push in a length of rope/string and soak it in silicone, then smear more silicone on the outside.
The rope helps to give the silicone support.

Bear in mind, it's best to jsut use a new gasket, the rope is really just a bush mechanic kind of thing.

TrackAttack · Postby **TrackAttack** » Tue Jun 30, 2015 5:57 pm

hks_kansei wrote:Rubber gaskets are usually fine as is, and may just need a few dabs of silicone near the corners (ie: Rocker cover)

Whilst normally true, in this case, these crescent seals will require sealant on both sides.

C-Gazer · Postby **C-Gazer** » Tue Jun 30, 2015 10:01 pm

Both sump seals /oil pan gaskets were new from Fab9tuning who also gave instructions which I followed about fitting the seals. I am now considering dropping the oil pan and resealing as a proper fix at the next oil change.