HT4100 4.1, 4.5, 4.9 Discussion, Your opinion of the 4.5L V8 in the 88 DeVille in Cadillac Engine Technical Discussion; Is this a good engine? What are some things to look for? concerns? What are the great things about the ...
The 4.5 and 4.9 are upgraded versions of the 4.1. They are responsive and provide adequate horsepower, and tend to be very reliable and long-lived engines. In fact, they remain two of the lowest warranty claim engines Cadillac ever produced. If the transmissions held up better, these cars would run to 300k and beyond.
There is one caveat: the cooling system must be maintained properly and regularly according to the GM instructions. As good as the 4.5 and 4.9 are, they suffer from the same primary weakness that nagged the 4.1: head and intake gasket failure due to the aluminum block/cast iron head design.
Changing the coolant annually and using the GM sealer supplement will drastically reduce your chances of ever dealing with these problems.
Automobile(s): 1991 Sedan deVille 4.9L/1994 Lincoln Town Car 4.6L
Chatham, Ont., Canada
Re: Your opinion of the 4.5L V8 in the 88 DeVille
Well, I would certainly HOPE there would be some improvement in the 16 year gap between the cars you mentioned...and just because a Ralph Lauren Polo t-shirt COSTS $100 doesn't mean that it's any better or more functional than the $6 one. If you are such a BMW fan/Cadillac hater, why are you here?
I think the 4.5L are great overall. Now I guess I like the later versions of the 4.5L better because of the fuel delivery system but I do not think that takes away from their dependability. A huge step up from the 4.1L. I would still buy one if the right situation came about.
Ok, now that the Bimmer crap has left us, I'll lend my take on the 4.5 liter, as I have owned both.
The 4.5 liter is very reliable in either the TBI or MPFI setup. Power is strong from a stop, but as everyone and their mother has stated, the 4.5 loses power up top.
As for fuel mileage, the 4.5 will easily get what your driving habits for a torque monster will allow; on my '89 Deville, she would average about 17 overall, and I am a leadfoot. Ask anyone here When I didn't beat on the engine (and they can take it!), I would see above 20 mpg at times. Like I said, mpg is partially a product of your habits, and the tune of your engine. On my '87 Seville with a transplant 4.5 liter, I am netting about 19 mpg.
Back to overall reliability, the 4.5 liter can take a beating, but with any engine and the reliability therein, that reliability depends on you. What I mean is that you must follow the proper maintenance procedures for this engine (coolant procedure anyone?), and keeping the engine in fine tune helps as well. Just common sense right there.
4.5L V8....a perfectly good american built pushrod V8. Nothing spectacular here, but nothing terrible. Loads of low end torque, great throttle responce, well above average reliability, few big problems. On the other hand, there's no aftermarket support for the 4.5L, but then again, there really isn't any wide aftermarket support for any Cadillac built engine. The top end power is lacking, but then again, this is a Cadillac luxury sedan, not a Trans Am. And lastly, since it's a V8 engine mounted sideways in an engine bay that isn't very big, it can be real tough to do plugs and wires.