: Blown Engine

03-10-08, 08:17 PM
I am new to the Cadillac Owner's Forum and hopefully some one can help me out. I have an "01" SLS Seville with 110K miles on it. Service engine light had been on for a couple of days and I did not have a chance to take it in and get it checked out. When returning home one evening, the engine started missing very bad and eventually died. I got it started once but it had a terrrible noise. Towed to a Cadillac dealer and the next day I received a call from them saying it needed a carbon cleaning and plugs changed. I said ok, go ahead. But in the back of my mind I figured I would get another call. Well I did and I was asked if I was sitting. I knew the news was not good. They had removed 3 plugs and when they removed #4 - Cylinder 7 - the bottom of the plug was missing and it looked like the piston (or something) had hit it. Solution - NEW ENGINE!!! $7000.00!!! Am I hosed? Salvage or repair? The car is in excellent shape for 110K. Everything else works. Any suggestions? Are Northstar's noted for this problem? Recall from GM?

03-10-08, 08:35 PM
No they are not noted for that. In fact this is the first time we have ever heard of this.

03-10-08, 08:51 PM
It is physically impossible for a piston to hit a spark plug in a Northstar, unless that piston is on its way through the cylinder head. BUT, valves fail (rare) and plug electrodes fall off (rare). Witness the running thread about the mystery piece found jamming an intake valve. IF there were a catastrophic failure in the timing/ignition system it's possible that extreme detonation could destroy a cylinder that way, but that's pretty far out considering the N* engine management system.

GM long block and labor, list price, dealer, install and troubleshoot, warranty, yep $7,000 would be in the ballpark.

Sure would like to know what trashed the engine....as Ranger said, "This is a new one......"

03-10-08, 09:20 PM
Thanks for the reply. I would sure like for you to be able to look at engine. The plug electrode is missing along with the inside porclein. We do not know what to do next. I have it setting back in my driveway. I'm no mechanic and have been told it is labor intensiver to drop the engine. I could take a picture of the plug and email it.

03-11-08, 12:46 PM
Have they tried putting 4 good spark plugs in and then seeing how she runs?

03-11-08, 04:51 PM
No, not yet. It made such a terrible noise when I attempted to start it after it died. It made the same noise when the Cadillac service tech. tried to start it. But, it might be worth a try. It sure is not going to hurt anything. Just wonder where the missing plug parts are.

03-11-08, 05:45 PM
They would have to be in the cylinder, unless they where small enough to get blown out of the exhaust port. That is probably what you are hearing.

03-11-08, 10:23 PM
you can save some money by putting in a used motor. your car is 7yrs old and a new motor would be nice but a used motor is ok too. there are lots of used motors in recycling yards.

03-11-08, 10:46 PM
Find a mechanic with a bore scope. They can look in the cylinder through the plug hole and see what is damaged or if there is still part of the plug in there. Fairly cheap way to inspect the cylinder without pulling the head.

03-12-08, 10:42 AM
Dollars to doughnuts the porcelain insulator (nose) broke off and went into the combustion chamber, taking the ground electrode with it. The knock is/was the piston smashing the ceramic and electrode into the extremely thin (.080" or so) quench area in the chamber. Even if the parts and dust were to eventually blow by the exhaust valves, the damage is done because the top of the piston and cylinder head now look like someone worked them over with a ball pein hammer. The cylinder walls are undoubtedly scored by the ceramic chips from the insulator, and its entirely possible that the top and maybe second piston rings are broken, further scoring the cylinder wall.

The bore scope will tell.

Take a look at the "specials - specials" on the www.rhinoengines.com (http://www.rhinoengines.com) home page, left side, upper corner. VIN 9 Northstar, '00 -'02, fully dressed, shipped, $4995. (Wrong picture: I called)

06-08-08, 02:18 PM
I have a 93 STS that also hit a spark plug. The motor started to run real rough and smoked bad. 130K miles with no smoke or loss of power. Something just let loose and I wasn't going to go into the motor to find out since I would have to send the core in when I ordered a new Jasper motor. I was curious if I could find something out by pulling the spark plugs and the 2nd plug I pulled (start at the front of the cart/passenger side) had been hid where the center electrode was bent to the side and the other one bent over. I had the new Jasper Northstar installed and 800 miles later the number 2 cylinder compression dropped to 60 psi. Jasper sent out a second motor and 1200 miles later the number 5 cylinder lost all compression. Right now my car is on a hoist waiting for another Jasper Northstar. This time Jasper is analyzing what went wrong with the 2nd motor before they send me another motor. Jasper motors are warrenteed for 3 yrs or 30000 mile. It gets old driving a loaner car while my STS is on the hoist. The Jasper motors did not get driven hard at all and 93 octane used on every trip to the gas station. I suspect the problem with the new Jasper motors are the valves since there was no knock/tick sounds just a shaking motor due to the lack of power in the bad cylinders. I certainly am exercising my patience in the matter since I have faith I will eventually get a good motor. The 295 Hp STS Northstar Jasper motor was purchased at approx. $5000 by the local Caddy dealer. Jasper has a good reputation from what I see and I am willing to give them an opportunity to get things right before I get negative.

Anyone else have any issues with the Jasper Northstars??

06-08-08, 02:50 PM
Swampbilly, Honest question: Does your 17 year old son drive your car ?

Never had any experience with Northstar by Jasper, but the shop has done a lot with GM and Ford engines by Jasper for boats and cars. No problems. Good machine work and careful assembly.

06-08-08, 04:20 PM
this is why you dont continue to drive with a known check engine light lit...