New 83 4.1l Owner

[Z51JEFF]

Hi,I recently bought an 83 Coupe Deville with 50,000 original miles.The car looks new and has always been in a garage.Im starting to hear alot about this motor and im getting nervous.If the motor is maintained and not abused,what can I expect.I maintain all my own cars.Is there anything I should look at now.The car seems to have a minor vacuum leak thats only detectable at freeway speeds when the car is in O.D,any help would be great,thanks.

[MagicRat]

These motors have two weak points:
1. The oil pump housing is aluminum, and wears out quickly, usually around 70,000 miles. This opens up the clearances in the pump and the oil pressure drops, especially at idle. The dashboard idiot light only comes on when the pressure is really low, by which time the bearings are already starved of oil.
Install a good quality oil pressure gauge - a mechanical one is most accurate. If the pressure falls below 30 psi (hot) at 2000 rpm, change the oil pump.
2. maintain the cooling system and install a good temperature gauge, again a mechanical (not electric) one is best. If the engine overheats, it will likely warp the heads and blow a head gasket. Again, the idiot light is useless, as it does not let you know of a hot condition until its too late.
Change the coolant every year or two as the aluminum block is very susceptable to corrosion.

If you keep an eye on it these engines can last a long time.

[Jed Rule]

You left out the worn camshafts at 40,000 and the triple oversized front main bearings at 50,000. Oh and the leaking intakes. Also don't torque the mains unless the heads are on the engine. You'll warp the block!
No kidding, it's in the shop manual.
Jeff, run like hell.
Sorry for the bad news but I worked for Cadillac 1973 to 1985. These engines forced me to quit.

[MagicRat]

Originally Posted by Jed Rule

You left out the worn camshafts at 40,000 and the triple oversized front main bearings at 50,000. Oh and the leaking intakes. Also don't torque the mains unless the heads are on the engine. You'll warp the block!
No kidding, it's in the shop manual.
Jeff, run like hell.
Sorry for the bad news but I worked for Cadillac 1973 to 1985. These engines forced me to quit.

Probably sound advice, but the leaking intakes, (coolant) is a maintenance problem, and the camshaft and bearing wear are oil pump related, as I discussed.
As far as warping the block, well, as with any engine, proper service procedures must be followed.
Prpoerly maintained, this engine is fine. Just don't take the shortcuts that most owners took with these cars.

My worst complaint with these engines is that they are almost as slow as the Cadillac diesel V8, that is, like molasses uphill in winter.