cadillac northstar engine

richnirma

I have a '97 cad sts. It was using a substantial amount of oil between oil changes (car had 46k miles on it when the problem started). The service advisor said it was a consumption problem and a decarboization would clear the problem. Three more decarbonizations later and the problem persisted. I was then advised (at 58k) that we would have to leave the car and that they would have to remove the engine, machine the block, put in new rings and pistons (thank God for extended warranties). It didn't cost me a dime.

Does anyone know if this a known problem with the Northstar engine or is this a fluke.

I appreciate any and all input.

Thanks,

Richard V.

armtdm

Do a search as there have been others at Edmunds who have complained of Northstars using 1 quart/1000 miles but you are the first with a rebuild.

Mr_Shiftright

Statistically every manufacturer is going to have to replace some engines, be it Toyota or Mercedes or Cadillac. Yours was just one of them. It would be interesting to know, however, what they found in there. If it was ring wear, that's not so bad, but if they had to rebore the engine, that would be of some concern since I'm wondering why the block did that.

021247

I too have a 97 cadillac with the Northstar engine. Using excessive engine oil is only one of the problems that I have encountered. Since around 43,000 miles the car has constantly increased consumption. At 52,000 it has reached one quarter per approximately each 750 miles. That should not be acceptable by cadillac for an automobile that cost in excess of 30K. I wrote to the head of Cadillac in May - - you guessed it, I never got a response. I was told by the dealership and the area service that oil usage is "Normal". My previous Ford Ranger (3.0 V-6) had in excess of 110K and didn't consume oil and it only cost 13K when new.

I have also had to replace an alternator (just outside warrant), an air compressor and drier (just out of warranty), a right front strut (just out of warranty) and had to pay a huge sum to have the throttle body decarbonized (primarily so that the accelerator would work properly).

This is my second and LAST cadillac.

For the NaySayers thinking the car has not been maintained - you are WRONG. We have had the oil changed at 3,000 miles each time instead of following the recommended mileage (don't remember if it is 6,000 or 7,500). If I were to do that it would routinely cause a change itself, only need to change the oil filter periodically.

Cadillac has known of this problem since at least 1995, yet nothing has been done.

Am I a dissatisfied customer, not I am not, I am a dissatisfied EXcustomer.

bolivar

This is a known problem.

Several people in the Cadillac (DeVille, Seville, etc) message areas have complained about the problem.

And yes, there have been engine rebuilds.

One gentleman had heads rebuilt, then new motor.

My 1995 started using oil, probably about 1 quart every 1500 miles, but a decarb has seemed to reduce it significantly.

Cadillac can't or won't do anything about this. I think with the alum motor, the power they are producing from it, and who knows what else, they probably don't have a solution for the problem.

And not all motors have the oil usage problem. And it is not caused by lack of maintenance.

sonjaab

I have a 96 Northstar 78k miles.
It has been using1 qt. oil every 1000 miles.
The dealer did the consumption test etc.
when new. They said usage "NORMAL"
I had a 90 4.9 new and drove to 120k
and it didn't use a drop of oil.
But both were (are) troublefree.
Check the edmunds sedan thread for more info.
Good luck............Geo

Mr_Shiftright

I don't believe oil usage is PER SE indicative of a problem. An engine can consume a reasonable amount of oil for 200K. Just because your car burns oil does not mean you may have cause for complaint.

I think a quart every 750 is too much for a low mileage car, but once you hit 100K or more, you and your engine are on their own...that's a lot of miles and engines do naturally wear. Why some wear faster than others, well, who knows...the variances of the manufacturing process, the maintainence level, luck of the draw, the way you drive, your climate. For instance, revving a cold engine way up (accidentally or whatever) a few times can cause some future harm.

adc100

Well, I do agree with him a lot. But yes, this is the luck of the draw using oil-some do-some dont. Iwould be unhappy at 750 miles/qt.. I also wonder If they knew it had to be "machined" before they tore into it. I can understand a bad ring, but reboring is a sign of age/real abuse. Perhaps the ring broke and scored the cylinder. But usually a broken ring will not do this. I am very curious about this.

BTW, how does the Northstar manage to go the advertised number of miles after losing its coolant?? Always wondered that.

Thanks

Mr_Shiftright

I believe it shuts down some cylinders and goes into a default limp mode that does not generate lots of engine heat. But that would be interesting if someone would post the engineering particulars. I really don't know exactly.

sonjaab

One of the guys on the Caddy thread said
something like thats why they hold 8.1
ots. of oil . To cool the motor when
loss of c0olant occurs......????????

dhanley

I think what happens is that one bank of four fires, then the other four. The non-firing bank still sucks air through, which keeps things from getting too hot.

dave

armtdm

Sounds more like the dealer is at fault here for not pushing for a rebuild under warranty.
But either way, I concur that I would not purchase another caddy.

Mr_Shiftright

No, can't be just oil cooling the engine...oil is not a great coolant unless the engine is finned and has a big blower over it.

bolivar

that talked about the 8 quart oil supply helping to support the no-coolant driving mode.

And this is just a WAG on my part. But I don't see why a 4.6L (Isn't that the Northstar size?) really needs that much oil. I bet if they didn't go with the big advertizing campaign about being able to run without coolent when the Northstar was introduced, the car could easily have been built with a 5 quart capacity. I also bet a lot of people in Cadillac wish they had never gotten into this advertizing.

And go look in your owner's manual. It has a lot of WARNINGS IN CAPITAL LETTERS ABOUT WHAT TO DO IF YOU EVER LOSE THE COOLANT AND KEEP RUNNING THE CAR! Mainly, CHANGE THE OIL!

Is there a Caddy mechanic or other expert that really knows if the car goes into a 'limp' mode and what it is if the car overheats???????

adc100

Oil isn't a bad coolant. Its about the same as antifreeze. Naturally water is better. Water =1. Oil=.58, Antifreeze = .6. I suspect that the reason there is more oil is because during extreme periods of heat the increased quantity will act as a reserve because heat is real hard on oil. That's why they tell you to change after that episode. I suspect they probably have fins on the bottom of the oil pan also. Every little bit helps. I'm surprised they don't specify syn oil. That would get you another 100+ degrees of protection. Interesting about the cylinders shutting down. That would be relatively easy to do by having two fuel shut off solenoids which would open and close depending on the temperature of that half of the block.

Mr_Shiftright

Yeah, but the oil isn't circulating in a radiator! Big difference!

I just had a look at a northstar Cadillac....man, what a pain to work on that engine! They really stuffed that big engine into a low hooded car with FWD (on this model anyway) and it's a bear to access. My sympathies to any Cadillac technician on a FWD Northstar. And there ain't much air circulating around THAT engine, I can assure you from looking at it.