V6 Rear Oil Seal Leak

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Page created by T Mar 24th 2007:

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Commodore VN/VP Series II 3800 V6 Engine. Click to Enlargen. Photo by 265grunt.

V6 Rear Oil Seal:

Rear Oil Seal Design:

The rear seal design is no different from earlier V engine designs whether a rope or neoprene seal has been used.

Tinplate Rocker Covers vs Positive Seal Rocker Covers:

The first difference is the Rocker Covers which are unlike the earlier tinplate type
that used the gasket to achieve a seal. The V6 type Rocker Covers use a pressure sealing design which is superior in its ability to contain blowby gases since the gases themselves force the Rocker Cover seal against its surfaces. 
V6 Rocker Cover showing the O-Ring type Seal. Click to Enlargen. Photo by Toranasaurus.
V6 Rocker Cover showing the O-Ring type Seal. Click to Enlargen. Photo by Toranasaurus.

No Tinplate Side Covers:

Unlike the straight sixes which have tinplate side covers for the valve gear, the V6 has a tightly
sealed inlet manifold (valley) so there's another place that contains crankcase pressure well.
As a result blowby gases find the next weakest place from which to escape which means the V6 engine places more gas pressure on the rear seal than the earlier tinplated engines.
Once the rubber seals in the Rocker Covers become hard, then leaks can appear from them.
Original thread
Followup Thread

Excessive Blowby:

As stated in the PCV page, excessive blowby gas is generated by gummed up piston ring grooves.
Injecting water mist into the Engine and steaming the pistons will clear the grooves and reduce the blowby gas to acceptable levels.


The causes of the problem are covered under PCV and Engine Life.

Seal Rework:

Submitted by a Holden Fan on Sat, 20/05/2006 - 22:19.
Just did the rear main the the tired old vn v6.
It was the rope type and we couldnt do it in the car, there was no room under there, so engine came out degreased the engine flipped it on its end and pulled the sump off (you could tell it was a usa built engine the sump bolts were shocking)

Lever the crank out to find less then 1 inch of the rope seal left!!!!!!!
The seal had left the end of the crank and was sitting in thousands of peices in the sump.

Put the new seal in and put it all back together, try to start it no injecter pulses FARK!!!!!!!

Re check every connecter in the car find 1 hidden under the dash that i must of pulled off reconnect it and turn the key fired in 1 split second and was loud as i only put the exhaust manafold on, take it for a drive come back and theres water under the car look around and the water is comming from the back of the engine, struggle to tighten the hose but manage, take it for another drive come back and park it.

15 mins later move it to wash it and theres oil under it FARK now im ready to burn the car.

Look under it and its comming from the inspection cover again so it must need rings. stuff it were gunna sell it to holden and buy a new barina.

Im just happy its not dropping 3.5 L of oil in 5 mins of driveing anymore lol.



Rear Oil SealThread 1



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