Which Cadillac engines to avoid?

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Is it just the HT4100, or are there other bad ones as well? Thinking about buying a used Cadillac, but I obviously would like a decent engine.
 
8-6-4 cylinder deactivation engine also, and Diesel Olds 350 powered ones. If you can find either, lol. They all blew up.
 
Northstar engines usually run well, but most mechanical problems require many hours of expensive work.

That is a reason I don't recommend most Cadillac cars.
 
Northstar! Tons for sale with "blown head gaskets" What really happens is the threads that anchor the headbolts corrode. The head lifts away from the block. Cost to repair properly is more than the car is worth. Usually happens anywhere from 80K on. As I understand they made improvements in the threads in '00 and another "fix" in '04' My old '99 DeVille was the nicest car I ever owned, but I would never own one again unless the owner can show the engine was properly repaired IE: threads drilled out and bolts replaced with studs. Mine let go at 110K. A friend has an older ('95) DeVille with 4.9. It is much more reliable but the car is not as refined. He is having problems with oil pressure, but that could be electronic. Fuel economy is nowhere near the Northstar.
 
Originally Posted By: Russ300H
Northstar! Tons for sale with "blown head gaskets" What really happens is the threads that anchor the headbolts corrode. The head lifts away from the block. Cost to repair properly is more than the car is worth. Usually happens anywhere from 80K on. As I understand they made improvements in the threads in '00 and another "fix" in '04' My old '99 DeVille was the nicest car I ever owned, but I would never own one again unless the owner can show the engine was properly repaired IE: threads drilled out and bolts replaced with studs. Mine let go at 110K. A friend has an older ('95) DeVille with 4.9. It is much more reliable but the car is not as refined. He is having problems with oil pressure, but that could be electronic. Fuel economy is nowhere near the Northstar.


There's a guy advertising a permanent fix for these on the local Craigslist for $700.
 
The 425-472-500 engines were the best Cadillac engines, but with today's fuel prices, they're too expensive to operate.
 
HT-4100 is not a good engine the v8 368 6litre known as the v8-6-4 is not a bad engine its the same design as the 425 7.0 litre and the 500 8.2 litre. the problems were the computer disconnect it and it runs forever.
The northstar is a wonderful engine until you have the head gasket problem the engine has to be removed to repair but not all of them have the problem. We dont use dex cool in them!
 
Originally Posted By: Russ300H
Northstar! Tons for sale with "blown head gaskets" What really happens is the threads that anchor the headbolts corrode. The head lifts away from the block. Cost to repair properly is more than the car is worth. Usually happens anywhere from 80K on. As I understand they made improvements in the threads in '00 and another "fix" in '04' My old '99 DeVille was the nicest car I ever owned, but I would never own one again unless the owner can show the engine was properly repaired IE: threads drilled out and bolts replaced with studs. Mine let go at 110K. A friend has an older ('95) DeVille with 4.9. It is much more reliable but the car is not as refined. He is having problems with oil pressure, but that could be electronic. Fuel economy is nowhere near the Northstar.



I agree
 
Originally Posted By: Stelth
Is it just the HT4100, or are there other bad ones as well? Thinking about buying a used Cadillac, but I obviously would like a decent engine.

How about a late 80-90's Cadillac Brougham with the Olds 307 or Chevy 5.0/5.7L?
Can't get much more reliable than that.

Gas mileage is nothing great but they are inexpensive to purchase/repair and super comfortable.
 
Originally Posted By: Russ300H
Northstar! Tons for sale with "blown head gaskets" What really happens is the threads that anchor the headbolts corrode.


Last I heard, GM will not sell a rebuilt Northstar engine. All of their replacement engines are brand new. That says a lot in their faith of the longevity of that engine.
 
Originally Posted By: Rock_Hudstone
Originally Posted By: Stelth
Is it just the HT4100, or are there other bad ones as well? Thinking about buying a used Cadillac, but I obviously would like a decent engine.

How about a late 80-90's Cadillac Brougham with the Olds 307 or Chevy 5.0/5.7L?
Can't get much more reliable than that.

Gas mileage is nothing great but they are inexpensive to purchase/repair and super comfortable.


Yup but the 307 in those is SLOOOW. And didn't they have carbs until 1990?
 
Originally Posted By: Chris142
4.1,4.5,4.9 and the 4.6 Northstar. Olds has a 4.0L version of the northstar and I'm sure it's junk too.


What have you got against the 4.5 and 4.9?
 
Not much wrong with the 4.1L from what I hear other than being underpowered/slow

4.5L is pretty solid IMO (have a 1990 deville w/ 4.5L 260k miles still going strong) only down side is if you have a to pass emissions and your air diverter valve goes toes up. no longer made and getting harder to find in junkyards

Early 4.9L (Northstar) had head gasket problems. I forget which year they they stopped being a problem 98 or 00 I think?

but as sad before if the head studs get fix properly that is the last HG a 4.9L will need. Once fixed I think they are as good or better than the 4.5L
 
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Originally Posted By: Texan4Life

4.5L is pretty solid IMO (have a 1990 deville w/ 4.5L 260k miles still going strong) only down side is if you have a to pass emissions and your air diverter valve goes toes up. no longer made and getting harder to find in junkyards

You can pop the diverter valve open and fix it with a little RTV if you don't feel like searching out a replacement. I've seen the RTV fix last over a decade.
Originally Posted By: Texan4Life

Early 4.9L (Northstar) had head gasket problems. I forget which year they they stopped being a problem 98 or 00 I think?

The 4.9 isn't the Northstar, that's a different animal completely. The 4.9 is basically a stroked 4.5 with a couple of other minor upgrades.
 
I had an 2007 CTS with the 2.8 V6. It was the worst engine I have ever owned. It had many mech. problems that Cadillac fixed but they could not get rid of a vibration at idle. They finally said that was how the engine was designed and they could not fix it. Their solution to the problem was for me to buy a new Cadillac. They have now discontinued that engine so I guess I was not the only one with problems. I only had the car for 1 1/2 years and the depreciation was $7000. This was a 2007 that I bought in 2009 and sold in 2011. I will never buy another Cadillac but especially be aware of the 2.8. Roger
 
Originally Posted By: eljefino
Yup but the 307 in those is SLOOOW. And didn't they have carbs until 1990?


Yes, the Olds 307 was carbureted until the very end. It was the last of a long line of Oldsmobile small block V-8 engines. Many Oldsophiles belived that it held many advantages over the Chevy small block, but GM simply dropped development of the Olds version after about 1985. The last version of the 307, in 1985, had an aluminum intake manifold, roller cam followers, and a very smooth operation. It had a computer-controlled Rochester Quadrajet carburetor. I had a 1984 version of this engine; it had the aluminum intake, but sliding cam followers. It also had a computer-controlled Qjet. Interesting little animals.

And you can repair the Northstar engine quite easily, even while still in the vehicle (although removing the powertrain cradle does make the job easier). The only proper repair is to install Timeserts into the block. Not Helicoils, but Timeserts. There are tons of improperly repaired engines out there and that's half of the reason this motor gets a bad rep. Most of them are long-lasting anyway. I had a '97 that was in the family from almost new at 39k miles until about 190k miles. The engine was never opened up; the transmission fluid was never even drained. It's a tough powertrain. Some of them do have issues, but a skilled mechanic can have it back on the road, with a permanent Timesert fix, for about a grand. If you can pick up a used one for a song, you can have a bulletproof runner for not a lot of money.
 
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