: Infamous Northstar Oil Leak



plefe
09-23-04, 10:43 PM
The oil pan is leaking on my 80K 4.6L 270hp Northstar Concours. The shop wants $800 to fix. Ouch! Standard procedure for this problem is to pull the motor and replace the dual pan setup. Without going into this kind of debt, is there a reliable time tested stop leak that won't hurt our sensitive motor?

majax
09-23-04, 11:50 PM
If you have a Concours its 300hp, I can't think of anything on how the lines of a cheap fix(but I dont know).

CadiJeff
09-24-04, 01:01 AM
someone will probably bust me on this but i have a slight oilpan leak (all of my aluminum block cadi's did) when I do an oil change I use the STP oil leak stop it seems to do the trick and I have never heard of it doing any damage to an engine.

Who said the northstar was sensitive?

realhighpockets
09-24-04, 09:21 AM
[Difference QUOTE=majax]If you have a Concours its 300hp, I can't think of anything on how the lines of a cheap fix(but I donít know).[/QUOTE]
First year Concours is rated @ 270hp. I've driven one and I can't tell a difference between it and the 300hp version. I think it was underrated. Why, I don't know.
As far as a cheap fix, It's a Cadillac N*, It's just shy of a race motor and they aren't cheap to repair.
Look for threads on oil pan leaks under the N* performance section using the search this thread button.

plefe
09-24-04, 09:30 PM
STP is an idea. Thanks!

CadiJeff
09-25-04, 02:33 AM
sometimes the simple answers work..............sometimes

Chrisfor172
09-28-04, 02:03 PM
I put STP in mine too. Seems to have stopped or very little leaks now. Also stop leak may work too. :thumbsup:

Ranger
09-29-04, 11:42 AM
If your talking aboutthe infamous "half case" leak $800 is cheap. It is usually more like $1800.

Dooman
09-29-04, 04:52 PM
Well, just got the bill.
What started as a coolant smell turned into an overheated engine. I guess the 99 STS failsafe is not so safe. New waterpump job turned out to be head gaskets. I took the time and replaced EVERY seal we could find, and the starter while we were in there..
$3700 and not even done at the dealer..

Anthony Cipriano
09-30-04, 12:26 AM
Well, just got the bill.
What started as a coolant smell turned into an overheated engine. I guess the 99 STS failsafe is not so safe. New waterpump job turned out to be head gaskets. I took the time and replaced EVERY seal we could find, and the starter while we were in there..
$3700 and not even done at the dealer..

Were the head bolt holes in the block timeserted? Did you use the recommended anearobic redundant sealant on the lower crank case half and the revised rear main seal as well as RTV at the intersection of the LCC seal and the rear main seal? Just curious...

Dooman
09-30-04, 07:19 AM
Not too sure there. I did not personally do the work, but the crank case was not split..I have a two page list of gaskets and seals now. all GM parts.

Anthony Cipriano
09-30-04, 12:02 PM
Not too sure there. I did not personally do the work, but the crank case was not split..I have a two page list of gaskets and seals now. all GM parts.

If the crankcase was not split then the "infamous Northstar oil leak" was not even addressed.

CadiJeff
09-30-04, 05:32 PM
Anthony, I am almost afraid to ask, but what do you think of the stp oil stop leak?

dkozloski
09-30-04, 07:29 PM
STP ponied up about $888,000 in 1976 to the FTC to settle the biggest consumer fraud case in history that centered around a whole range of products that didn't work as advertised. That ought to tell you all you need to know about that outfit.

jameslwalker
10-31-04, 06:54 PM
I had leak on my '99 deville, with about 60k miles. It is still under warrantee (certified), and they said it costs about $2,000 to repair. I let the dealer do it, since it didn't cost me a dime.

blb
11-04-04, 12:51 PM
This thread is interesting for a couple of reasons.

First, I had the Norhtstar crankcase halves sealed by the dealer in 1996 under warranty on my 1994 STS. Most dealers denied there was any problem, but after obtaining a copy of the TSB outlining the problem, I was able to get one dealer to admit there was a problem and actually give me some insight into the prolem after talking to a technical representative at the GM Tech. Center. AT that time (1996), the dealer claimed that the porosity issues with the aluminum blocks that supposedly caused the leaks had all been straightened out and due to better casting methods and machining processes, after 1996 this problem would no longer be an isssue. Fast formard to 2004, and we find out that by 1999 the exact same issues still existed in the Northstar motors.

The other interesting part of this thread is that certain people always blame the ongoing Northstar headgasket failures on failure to maintain the cooling system. Yet, we see these headgasket failures on 1999 and 2000 Northstars, that have under 100,000 miles on them and therefore aren't even due for the first coolant change.

I'd be interested in hearing the reasons why GM just can't seem to get their act together to prevent these ongoing issues.

No More Cadillac's
11-04-04, 06:03 PM
I would be interested too. As GM is ruining the reputation of a grand old line

Ranger
11-05-04, 05:14 PM
I can't help but wonder how much more weight a cast iron block and heads would add and how much would that hurt fuel milage? Bring back the tried and true cast iron engine!