Hi all ,., I was wandering with proper maitenance of the 4.9 motor and transmission, on my 92 deville how many miles can i expect to generally get out of the car, until the transmission and engine may experience problems? What is the most miles you know of someone having with the original motor and tranny?

The engine usually outlasts the transmission 2:1. I have 220k miles on my 4.5 with no work ever been done on the engine. These engines with hardened cylinder sleeves can last 300k miles plus.

The engine and trans on my '94 Deville 4.9 run perfect at 134k miles. Just treat both to oil changes, and they will last!

My '91 DeVille has 221,500 miles on it. I bought it at just under 200K, and I don't know if anything has been done to the engine. It runs beautifully. Smooth, silent and plenty fast for me.

I had the transmission rebuilt in June at about 215,000. I was getting the VCC engagement error code, and since this is my daily driver, I didn't want to risk having the tranny blow on me. The mechanic showed me some of the parts from the old one; they were pretty well worn. But other than the VCC, I was having no trouble with it.

I'd like to see this car make it to 300,000 miles. I change the oil every 3,000 to 4,000 miles or when the oil life indicator drops below 25%. I've been using Valvoline Max Life since an oil change in February; there are still a couple of minor oil leaks, but they are smaller than before.

My 93 Deville has 298,000 miles on it. Absolutely nothing wrong with the engine.

One thing nice about this vintage of car is that there are a lot of them in junkyards to parts are cheap and easy to obtain.

my dads has about 103,000 miles.

some problems were sensors dying. cam sensor, and ign module was changed. had an oil leak around the oil filter area screw (bolt) was tightened I think it was the oil cooler or something was not on tight. engine is pretty good. regular oil changes and filters. should last..

I once bought a 90 Fleetwood for $450 to fix up my 90 after a deer impact...it had 280k miles on the clock and I threw my plates on it and drove it home. I should have kept that car instead of fixing my 90 :(. The 90 has 173k miles, and has developed a dead cylinder. Instead of spending hundreds of $ on trying to figure out the problem (my guess is a dead injector) it also had a slight oil leak, I found a 91 with a beautiful body and cabriolet roof for $550. It runs way better than my 90 ever did, and going to a 4.9 after a 4.5 is a treat! It has 220k miles and rides and drives like dream! No clunks thunks rattles or leaks, and the electronic transmission is beautiful. I guess the point of this oversized post is that the 4.5/4.9 engines are damn near bulletproof, and will run for many many miles even if abused/neglected. Oh yeah, all three have/had that icky bearing knock at startup. *shrug*