Last post on Dec 04, 2013 at 1:04 PM
You are in the Cadillac DeVille
What is this discussion about?
Cadillac DeVille, Sedan
#1603 of 2635 Re: Cadillac DeVille - Northstar engine - Problems? [alston28]
Oct 15, 2004 (4:33 am)
I bought a new 2000 DTS and experienced 1 qt/2000 miles oil burning during breakin - which was up to 15000 miles. Have been using synthetic 0W-30 and now use less than a quart in 5000 miles. Have 50000 miles on the DTS (all highway) and it is AWESOME> Only engine problems have been crankshaft sensor went out at 5000 miles and replaced under warranty. Service manager said they had some bad ones that were showing up in the 2000 model but I haven't heard of the problem in later model years.
#1604 of 2635 Re: Cadillac DeVille - Northstar engine - Problems? [alston28]
Oct 15, 2004 (4:40 am)
My 2000 DTS developed a "cold carbon knock" - loud clicking at cold startup much like a noisy lifter - which service manager said was caused by deposits from mid or premium fuel. This was at 35000 miles They ingested a GM product through the throttle body which corrected the problem under warranty. I was told to use regular or midgrade fuel and every 1500 or 2000 miles give it a good dose of Techron through the fuel tank.
Oct 16, 2004 (12:43 am)
Also give all Northstars a few doses of Wide Open Throttle every week or so. This is the best solution for the 'carbon knock' and also will cure a lot of the high oil consumption problems.
Run it to redline in the first 2 gears. This will break up carbon, and freeup the rings. Carboned up rings is the cause of the oil consumption.
Other than the dozens of problems that can occur with the complicated electronics on such a car, the main other problem is blowing a head gasket. If there is a loss of coolant, with no external leakage, (or of course running hot), the Northstar may have a leaking head gasket. It does not leak into the oil, it goes into the cylinder and is burned out. If this happens, you have a multi-thousand dollar repair. The motor must be pulled. When the heads are removed, the headbolts will strip in the alumium block. The bolt holes will all have to be redrilled and retapped and a special insert screwed in. Big money. Some dealerships don't even want to do this job. It will be from $2,500 to $5,000 or whatever they think you may pay. I've read of headgaskets going on less than 50,000 miles. When 100,000 miles come up, this can turn a Cadillac worth a few thousand dollars into something not worth rebuilding.....
#1606 of 2635 RE: northstar
Oct 16, 2004 (6:00 am)
Someone I know had the water pump fail on a 99. The engine overheated which was his first clue that something was wrong. It was the water pump. But a year later the engine called for more coolant. Then, after a bit longer, it wanted more coolant again. At this point the service department realized that something was wrong. A head gasket was leaking. They took the engine apart, but were not able to put it back together because they could not get the bolts to seat. I don't know if a head was warped or what. They replaced the engine.
If he had paid attention to the coolant level, he would probably have noticed the water pump beginning to fail, and perhaps everthing else would not have happened. But, a new northstar is now about $5000, so the cost of replacement is not too bad.
#1607 of 2635 I HAVE READ ELSEWHERE
Oct 16, 2004 (10:02 am)
The thread holes in the N-star block strip out easily and are a nightmare. They have been using "timeserts" in the blocks to be able to put the bolts back in.
A fella over at cadillac forums had a heck of a time with his.................
#1608 of 2635 1990 deville running rough
Oct 16, 2004 (4:59 pm)
I have put new plugs, wires, cap and rotor and also getting a code 41 which is camshaft position sensor. I replaced it and the code comes back and there is no change. Any ideas would be appreciated.
#1609 of 2635 RE: northstar [sls002]
Oct 16, 2004 (10:57 pm)
The failed water pump, and running somewhat hot probably had little to do with the gasket failing later. A Northstar can be run very hot a short distance. It shuts down 4 of the cylinders, then switches to the other 4 to run in a hot, limp home mode. It is supposed to be rated to run 50 miles at 50 mph or less in this mode. I would not do it to my car, unless the devil himself was chasing me. I would have it towed.
And the heads usually don't warp. The shop people were stupid in not knowing the head bolts have to be timeserted if the heads are removed.
And, yes, water pumps fail a lot. A Cadillac dealer will definitely have one in stock and can very quickly change it out, since they see a lot of this.
#1610 of 2635 RE: water pump
Oct 17, 2004 (9:03 am)
Actually there are kits that allow replacement of the seal and other wear parts so some of the pump is reusable. I caught the water pump on my Aurora going (leaking) and brought it in for repair before it got bad. The 50 mile limitation is mainly that the oil is slowly turning to sludge.
My friend had his 99 towed after it got hot rather than drive it in. It is hard to say if the brief overheating caused the problem, but most likly did make an existing head gasket problem worse. The shop people were able to get one head put in, but the other would not go. They were in contact with Cadillac and Cadillac paid for part of the out of warrenty engine to be replaced. I am quite sure that everything that could have been done to save the old engine, was done.
#1611 of 2635 RE: northstar [bolivar]
Oct 18, 2004 (4:34 am)
Other than the obvious - leaking or high temp reading - are there any other aymptoms of a failing water pump on 2000 and later Northstars?
#1612 of 2635 Water pump failure
Oct 18, 2004 (6:21 am)
My service manager said that the water pumps sometimes fail at 25000 miles, while others last for 100,000 miles or more. My Aurora's pump failed at 50000+. Apart from noticing that the pump is leaking, which is not really easy, but you may notice coolant on your garage floor, the best thing to do is keep an eye on the coolant level in the reservoir. If you are in the habit of checking the oil weekly, its easy to just look at the coolant level in the reservoir with a cold engine. If it suddenly is lower, then there is a leak.