View Full Version : The InFamous N* Oil Leak - Oil Manifold

01-29-14, 10:07 AM
What did the factory do to solve this?

When did they do this?

What is then difference of factory solving
compared to early warranty repairrings
on 1993-1994s

01-29-14, 10:12 AM
What infamous oil leak? Oil manifold?

01-29-14, 10:39 AM
Sweden - Something lost in the translation here .............. Are we talking about the oil filter adapter, the lower halfcase, or the internal oil distribution plate (manifold).

Oil distribution plate - and it requires complete engine removal and disassembly.......... AND GM says "Use a new one every time.".

01-30-14, 04:20 AM
The InFamous N* oil leak in the oil manifold is in the upper part of
the plate between oil pan and the crankcase - thought everyone here
knew this. And the leak is on the upper part of this plate - why this
is a bad contruction from the beginning I don't know.

01-30-14, 06:29 AM
There is a revised procedure to reseal with current distribution plate........



Post #23 on.....

01-31-14, 03:53 AM
But how did the factory solve this in the production and when?

01-31-14, 08:35 AM
I don't believe that GM "solved" the potential problem during the production run - up to at least ? 2004 ? - after that, a TSB (Technical Service Bulletin) was issued outlining new oil pan and halfcase re-seal procedures using the then-new GM Gray RTV sealant - Permatex UltraGray.

I think that Jake or Evrett at NorthstarPerformance have quite a bit of insight here - they were involved in remaining stock purchase at the closing of the Livonia engine assembly plant. Many posts and pictures on this a few years ago.

Very specific seal procedures without using the original silicone seals. The new oil distribution manifold incorporates a new seal.

........... and it's not an infamous leak because many - the majority - Northstars do not have halfcase or oil pan seam leaks.

02-01-14, 12:15 AM
All Northstars will have oil leaks at a certain point in time. It's inevitable. In 04 they really screwed up and stopped machining the half case seal groove right up to the rear main seal area... there's about 3/8" of area without any seal. I'm surprised they don't leak more.

Essentially there are certain things you can do to extend the time before seepage will occur from a total re-seal. It involves careful surface preparation and the use of both rubber seals and RTV.

Sub you're close, but it's not Permatex Ultra Grey to my knowledge. the GM sealant is quite a bit thicker (if you don't have a pneumatic/electric sealant gun it sure gives your arm muslces a workout squeezing the trigger).

I will catch up a bit more tomorrow with all of this.

02-02-14, 06:17 AM
I had my (allante 1993 which leaked when I bought it with 67,000 milage
and 6 years of age) Engine out and resealed (and heads done) at slightly
more than 100,000 milage - I didn't have the manifold plate changed but
resealed with black loctite Quick gasket - the original o-ring gasket was
not broken or something - leak was because of flatness - so it was kept
and resealing was made all around and outside this o-ring gasket.


I Think it is this one - hope it will solve the oil leak for the rest of my car's Life.