How long will a 4.5 DeVille last?

Keep up proper maintenance such as the coolant changes every two years with additive and it will last forever. The 4.1 was the more troubling engine but they had most of the kinks worked out by the time the 4.5 was introduced. The engine in my Fleetwood was not maintained at all. I don't think the coolant had ever been changed once before I got the car a year and a half ago. It now has 68k miles on it and still purrs like a kitten every time I start it up.

the trick is in the maintenance.....based on the age and condition you have, flush the coolant, make sure you use the sealant tabs and it will be good for the long haul.

typically the fastest way to junk these engines is with improper cooling system maintenance, they are sensitive to that.

Family wide we have had probably 9 4.x cars, all of them crossed the 150k mark, and typically we get sick of driving them when they hit 200k~225k....not that there was anything wrong, you just want to look at something different. its the rear drive 4.1's that are delicate (the 4.5 FWD is from the same family, but they started working the bugs out)

:yeah: You'll be bored with it before it dies. You'll have the first round of standard chassis wear (brakes, shocks, etc.) around 100K. Rebuild that and good to go for another 100K.

I have a 4.5 in my STS with 217k on it and still going strong. No problems. I don't know why people got such a bad taste about these cars or engines but my has been and continues to be loads or fun.

The biggest problem I've had is AC compressors.

I have a 4.5 in my 1990 Allante. It has 142,000 miles and runs strong. I just bought it about six months ago so I have no idea about it's maintenance history. It does look like it was taken care of as the car is in excellent condition overall. I hope it will go another 50,000 without any problems.

just stumbled onto this topic as I paged thru the forum. I live down at the Allante forum. Reason that I'm posting is that I am parting out a 90.5 Allante with a 4.5 (99k) and am struggling with the idea to save the engine and tranny or scrap with the car. Struggling I guess as I just changed seals and it still runs strong.

Sell it or scrap it gentlemen is the question.

before my 90 deville got crashed it had 170k no cat, went like hell and got excellent gas mileage.

wcoates said:

just stumbled onto this topic as I paged thru the forum. I live down at the Allante forum. Reason that I'm posting is that I am parting out a 90.5 Allante with a 4.5 (99k) and am struggling with the idea to save the engine and tranny or scrap with the car. Struggling I guess as I just changed seals and it still runs strong.

Sell it or scrap it gentlemen is the question.

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I would save the engine and especially the tranny. The F7 tranny has a unique valve body. You could also just pull off the intake manifold and heads from the engine and the valve body from the transmission and part the rest out.

wcoates said:

just stumbled onto this topic as I paged thru the forum. I live down at the Allante forum. Reason that I'm posting is that I am parting out a 90.5 Allante with a 4.5 (99k) and am struggling with the idea to save the engine and tranny or scrap with the car. Struggling I guess as I just changed seals and it still runs strong.

Sell it or scrap it gentlemen is the question.

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Down to the engine, tranny, steering column and rear fenders and then to its final resting place. Anybody interested, give me a call 330-559-6690.

Bill C

Wow I just noticed a glaring typo in my previous post

my = mine, obviously

mine is still going strong on with 130,000 on the clock but its realy got 190,000 on the engine

:thumbsup: I owned two 4.5L Cadillacs. An 88 Deville and a 90 Deville. I'm driving the 90 Deville now. Its a great car with 25 mpg average. I'm at 115000 miles now and it drives great. The 88 Deville i blew the head gaskets when I got it stuck in the snow. Mia culpa. My uncle sold Cadillacs for 30 yrs and he said the only year you shouldn't get is the 87 with a 4.5L. He said those cars had design flaws but they were fixed for 88 and later models. If you take care of any the car then it should last a long time. Don't blow a gasket okay:excited:

They arent the most reliable engines out there. Sometimes they last and sometimes they don't. If you like it drive it and don't think about it.
And 1987s didn't have 4.5.

The 1987's had 4.1L engines in them, however, they were much improved from the older 4.1's. In 1988, the 4.5 was introduced and it incorporated roller cams/lifters and came with much more power.

Edahall said:

I would save the engine and especially the tranny. The F7 tranny has a unique valve body. You could also just pull off the valve body from the transmission and part the rest out.

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how difficult is this?

wcoates said:

how difficult is this?

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Once the transmission is out, it's not all that difficult to remove the valve body. The valve body is right above the pan however, there are many bolts holding it together. Since these solenoids are nearly impossible to find, they should not be sent to the junk yard and melted down.

My '88 Eldorado just turned 130K. Runs Strong with no problems. Again maintenance is the key!!!!

I am looking to buy a 1988 deville. it has 38.000 miles on it. I have no way of knowing what was ever done if anything or how long car sat. Will this car be ok if i get it and dump the coolant? what else should I be looking for when I inspect it ?

Look for leaks, everywhere. Gaskets and seals don't hold up well when a car sits. If it sat outside check for rusted brake and fuel lines.