View Full Version : Rear main (probable) seal leaking... talk to "Northstar performance" or no?

05-05-11, 11:27 AM
So I have had me '02 seville sts for around 8 months. It has had problems, some I got fixed, others didn't show up till after the 90-day warranty was up. about four months ago, I started smelling burning oil. Took it in for an oil change (it was about due anyhow), and they told me I should get my oil leak checked out since they could not tell where it was coming from. Since my wife and I are pretty broke, we let it sit, only driving it a couple miles a week/month till yesterday. As I suspected, it was not the head gasket (although we still aren't sure there is in fact nothing wrong with the head gasket), but the rear main seal (dealership said most likely, but hasn't confirmed yet).

The dealership gave me an estimate of $2793.75 to fix it (plus more for the other issues I had them check out).

My question is this: Would I just be better off trying to get my car or engine out to Northstar Performance, and have them redo my whole engine? or should I just take this terrible hit now and hope my head gasket doesn't go within months after getting it back?

The car is sitting at the stealership waiting for my decision. I also need to get a brake control module i guess? (had a "service stability system" code come on and off at random intervals) They told me the part alone was going to run me $1085, so this trip is going to cost me over half of the amount I paid for the vehicle, I would like to reduce that cost as well as the chances of incurring more as soon as I get it back. That is why I ask. If I have to spend a little more to get the job done and do preventative maint at the same time, I would rather go that route.

05-05-11, 11:45 AM
did your rear seal leak show up after you changed your oil? maybe they had a qt of stopleak in the oil. who knows. snakeoil stuff usually does not work. might try and talk to a tranny shop about pulling your trans and putting in a new rear seal. they are experts at yanking the trans.

05-05-11, 11:50 AM
How bad is the leak? Usually it's nothing more than a little seepage you can just live with.

05-05-11, 12:19 PM
It isn't a bad leak per-say... it only drips a spot smaller than a dime if left sitting for over two or three weeks (starting it for five minutes once a week). When you drive it, that's when it becomes obnoxious due to the burning and smell coming into the cabin. I will take it out for a 5mi drive just for sake of driving it every once in a while and when I park, or am at a light, you can watch the smoke seep out from the edges of the hood, and admire it in the headlights at night. It's not thick and billowy, but thin and wispy. Still stinks to high heaven.

05-05-11, 12:22 PM
did your rear seal leak show up after you changed your oil? maybe they had a qt of stopleak in the oil. who knows. snakeoil stuff usually does not work. might try and talk to a tranny shop about pulling your trans and putting in a new rear seal. they are experts at yanking the trans.

The burning smell came right before my second oil change and they only noticed the leak during the second oil change. I have recently suspected the seller of doing something along those lines to make the sale. Lemon laws only protect the buyer for 3,000 miles, after that it's on you...

05-05-11, 12:37 PM
I think you'd be well off to continue driving for now until it gets a bit worse. I'd be happy to help as soon as I get caught up a bit.

It makes sense to get it all done at once. Other than the drive time and fuel costs, you'd save a fair chunk of change and get everything done before the HG's fail.

Totally your decision. I'll help any way I can.

05-05-11, 02:01 PM
This was my PM to 97eldocoupe, but since I have too few posts I couldn't send it. Please excuse the repetition from the original post.

My name is Shane, I recently picked up my third North* seville STS (first was a '94, then a '93, now an '02) after returning from Iraq. Found it online, picked it up in Long Island NY (I live in northwest CT). I have been wanting this car ever since the 1998 redesign. I picked it up with 67K miles, there were some minor problems we handled some, and figured we could easily handle the rest. About 6500 miles (four months) after driving it home, I started to smell oil burning. I took it for it's second oil chance since purchase and the guy tells me I should do something about the leak. I ask him where it's coming from, and he says "I'm not sure but it seems to be coming down from the back of the engine."... So I let it basically sit for a few months and drove my Jeep around instead, only driving the caddy for a few miles (down my road and back) to keep it running and the battery charged. I would check the spot where it sat for oil and usually there would be none unless I let it sit for over two or three weeks and even then it would be a spot under the size of a dime. I figure it was most likely the rear main seal leaking and not the head gasket since it was an external leak and there was no evidence or oil and coolant mixing anywhere in my engine.
Yesterday, I took it in for some daig work at my local cadillac dealership (NY is too far and my used car warranty is up), and they came back to me telling me that it is very serious, they are pretty sure it is in fact my rear main seal, but won't be certain till I give the go-ahead to pull the engine and fix it.
The estimate they gave me was $2793.75 just to do that (more for the other things I need done to the car). All the work I need done will total around half the purchase price of the car (I paid $10,000, and the total will be around $5,000).... still owe around $5000 on the car itself, so selling it is going to hurt more than help, plus I LOVE the car, just wish I could drive it without worrying so much!
So the question is, would I be better off trying to find a way to either get my car or engine out to you to do the head-studs and redo the seals? I am concerned that once I pay for all this work, my head gasket will be the next thing to go, and most likely only months after I get it back from the dealership.
I have heard/read nothing but GREAT things about you guys, but we are tight on cash (like everyone else), and don't want to have to pay for redundant work.

If you could please reply with any questions or answers you may have as soon as you can (since the car is at the dealership waiting for word from me), it would be greatly appreciated! Also feel free to post a reply in my thread if you would like.

Thank you,

How bad is "worse" before it is a real problem? If it's okay to drive around like this, I would love to be able to drive it out, but finding time to do so will be difficult. So when it gets worse, make an appt, drive out, and bring some oil for the drive? I know that the dealership is going to try to tell me that this problem needs to be fixed ASAP or I'll be doing irreparable damage by driving it anywhere, because they want the money for the job. I don't know, however, if this problem could become very serious in a heartbeat or not.

I can tell you almost anything you might want to know about Jeep wrangler TJ because I have done almost all my own work on mine, but aside from features, grabbing codes, and oil changes, I know next to nothing about the cadillac's systems, least of all, how the computer ties into just about every system.

This story is from the summer of 2000:
My 94 sts had a split second loss of ALL electrical items on the highway once. EVERYTHING went dead for literally a fraction of a second at 75mph. The gauges, radio, heat/ac, everything, for just that moment, the only sound my car made was the tires on pavement, and then everything was back to normal. It didn't throw any codes, and it was as if I had imagined the whole thing.
That night I heard a very slight *ting* as though someone was lightly taping on the manifold with a plastic hanger at idle. I took it to the dealer, they listened and said not to worry, probably just one of my exhaust hangers rattling. When I mentioned the electrical failure, they checked for codes and they guy said there was nothing of note in there.
So I took it out for a road trip down to Maryland. Half way down you could hear the tapping from inside the car at 65mph. The "check engine light came on as we were leaving our destination and I figured I'll drive it back home and have the dealership look at it again. While we were heading back, it was gradually getting louder and louder till you couldn't hear anything else....
My car blew up outside of Wilmington Delaware in the fast lane going 60, cas in the slower lanes were going faster, and nobody could see anything due to the incredible smoke screen I was putting out, and I needed to get over two lanes to reach the shoulder. We got to the shoulder without being hit (A miracle!). My windshield was covered in oil, the highway was covered in oil mapping my path to the side of the road, and the rest of the oil that was left, was creating a slight river off the highway into the storm drain.
Had it towed up to the local dealership (in CT) after the place in Delaware quoted me $16,000 (more than I paid for the car in the first place). The local dealer said $10,000. At the shop, we removed the engine and tranny to see that I had three holes in the engine block and shattered a 3inch hole in the transmission casing. You could look through one of the holes in the bottom and see light pouring in through the top. Thing looked like someone took a shotgun and fire slugs into the engine.
Turns out, that the loss of electrical was the first indicator. At that time the piston head got stuck in the top of the cylinder and the piston rod broke free. That was the slight *ting*... Not my exhaust... The rod ended up sliding along the cylinder wall for a while before it started to do damage (hence it getting gradually louder). I never got word on why it threw the rod in the first place, but I did have to buy a whole new engine and tranny.
Drove it till about 100K miles (on the car, only about 20K on the engine), before the electrical systems started getting severe gremlins. At 120K I had to sell my baby due to computer and electrical problems just becoming too much of a financial drain.

The reason I tell this is to explain that before this incident, I was care and worry free about my cars. Did the proper maint, but other than that, didn't really worry. After that incident, I worry about EVERY single new sound, vibe, glitch, and code. I know how my cars sound and feel when they are running perfectly and if anything seems not right, I start to get paranoid after that fateful day.
That is why I ask if it is okay to drive it for a while as is.

05-05-11, 04:23 PM
The Northstar engine is known for oil weeping via the crankcase (at least from what i know), rear/main seal(s)as well. If it's just a few drops at a time (as in most cases) then continue to drive it. however you note smelling burned oil, which suggest to me that its more than weeping, suggestion would be to get the sealing and HG done at the same time, again if the block is just weeping.

05-05-11, 04:39 PM
It does smoke and burn, but I assumed it was because whatever was dripping was hitting the exhaust and burning off. Might it only be leaking while running? and therefore while it's parked, it no longer leaks and that is why there is so little evidence on the ground?

05-05-11, 05:06 PM
My engine weeped while parked, i would say a drop every few hours, not much at all.

05-05-11, 07:04 PM
If it where me i would not spend 2700 to have the leak fixed if i where going ot spend that much i would have the entire engine overhualed and throw in jakes studs
just for the hell of it even if the hg's are perfect now cause with the luck some of these caddys put us threw chances our in a year your hg's might be gone and have to pay for the work all over agian

but personaly for a small leak like that id just let it go and wait till i had to do the job if and or when the hg;s fail take the time save up some extra cash on the side don't strain yourself if it doesnt need ot be done unles syou really can't stand the oil then go for it now but i wouldnt spend that much without having the heads done also just stud them to be safe

05-05-11, 10:31 PM
Alright, I'll give a little time, allow Jake to get a little more caught up, and see about taking a LONG ride out, bring a few quarts of oil, and watch my thermostat and exhaust while on the trek. Seems like the plan most agree upon.


05-05-11, 11:01 PM
if your not overheating and your hg's are fine and not looseing coolant anyware
at themoment and only looseing oil then i wouldnt even worry about the temp watching the needle or tach just drive it till it starts to overheat and then take it up to joke for a overhual rebuild job

or when ever you want before that for the oil leak and hg whyll its already being done

if its not over heating at the mement i wouldnt even watch the tach no reason to

05-06-11, 01:01 PM
could be the rear seal. might be a valve cover gasket too. or the case half seals.

05-11-11, 08:30 PM
I say keep adding oil - you can buy a lot for $2,700. And that brake module can probably be had used for a lot less - IF that is what's wrong - usually, it's the steering wheel sensor on these cars - at the base of the column and an easy and cheap fix

05-13-11, 01:27 PM
I say keep adding oil - you can buy a lot for $2,700. And that brake module can probably be had used for a lot less - IF that is what's wrong - usually, it's the steering wheel sensor on these cars - at the base of the column and an easy and cheap fix

I have a lot of things that need fixing, but I don't feel right about buying used automotive electric parts. For the ECBM, I'm going to send it out for a remanufacture, and reinstall myself (hopefully it really is as easy as everyone here says.

05-14-11, 11:32 PM
I have a lot of things that need fixing, but I don't feel right about buying used automotive electric parts. For the ECBM, I'm going to send it out for a remanufacture, and reinstall myself (hopefully it really is as easy as everyone here says.

The EBCM isn't hard to replace....I would have no problems using a "used" EBCM.....it will either work or it won't....and for reference...I replaced mine with a used one, and it's worked for about 100K.....part cost me $100 instead of $1000!

I'm in Colorado....so it's not like we get a lot of rust...but I've had SEVERAL little electrical problems, and almost all of them have been solved by VERY patiently chasing wires until I found a bad connection.....sometimes even having to check resistance while moving the harness around to find an intermittent problem.

Not sure about the 02, but on my 97, the EBCM is conveniently located right below the waterpump, thermostat and the upper and lower radiator hose....it gets wet pretty easily, and that connection can be a problem if it gets it's share of antifreeze on it. Before I replaced the EBCM, I'd disconnect and clean the wiring connection...not many things more frustrating that replacing a part, only to find out the connection is all that was bad....and if you let the dealer do it, they won't exactly be straightforward about the real problem.....

If you have a Northstar that doesn't leak oil....you have a HUGE issue.....you engine is out of oil!!

Good luck, and if you ever get to Carson, look me up.

05-17-11, 10:04 PM
Thanks Falcon. I think I'm going to send it out to module masters, $150 + S&H, not bad.
I am also planning on taking a long road trip/vacation to the great white north to see Jake, and get the whole thing redone. Till then, I'll work on the smaller items like Wheel bearings, int-steering shaft, tie-rod ends, two new rims to replace one thats bent and another that is scuffed, peeling, and bubbling, and the other issues my car is currently having problems with.

05-23-11, 01:28 PM
I have a '94 concours with a bit over 104K miles. Since I purchased the car it has leaked oil. Down here they quote around $4,000 to pull the engine and re-seal it. The alternative is an $8.00 drip pan, and a reduced sense of smell! I don't have much of a problem with that, my wife and daughter are a different thing, or breed! Not only is the smell offensive, but they are embarrassed by it as well. Like when we park in the supermarket lot, and the smoke drifts from under the hood, you can see them cringe. In a few weeks my daughter graduates from High School, and I said I would have the car detailed, even shampoo the interior, as the caddy is the most comfortable of our vehicles, and I was told, no, we will be renting for the event! At any rate 2 years of driving, about 20,000 miles the engine is strong, the car runs great, and I have replaced the drip pan only twice. You might try that!