HT4100 4.1, 4.5, 4.9 Discussion, HT 4100 4.1 motor problems - giving up in Cadillac Engine Technical Discussion; I have a 1985 Fleetwood Brougham which is loaded, and even has a moonroof that works. When I test drove ...
I have a 1985 Fleetwood Brougham which is loaded, and even has a moonroof that works. When I test drove the car three years ago, it rode wonderfully but I soon learned after buying it that it definitely did not like the highway! It ticks after a highway drive and a slight bottom end knock can be heard, depending on how long it's driven on the highway. However, the car has run like that for the entire length of my ownership, and I've never broken down in it. The motor's noises have not become any louder over time, either. Some have suggested I just keep driving it like that, but it is worrisome on trips, to say the least. There is some rust, but other than that the car is worth putting in a motor. My question is if anybody knows if the 4.1 or 4.5 replacements are even better, and worth the $4,000 I'm being quoted for the installation. I'm told those are the only motors that can be put in due to the bolt patterns, etc. I'm not a mechanic, so cannot do it myself to save the money. If the same problem will occur down the road due it it being the same type of motor, I'd just as soon sell the car to someone who can do the work themselves and give the car a better home. If anyone is interested in it please feel free to let me know.
This is a RWD car so a 4.5 upgrade is not one of your choices. You need a RWD block such as a Chevy/Oldsmobile 350 or Cadillac 368. If you're going to keep the same transmission, you'll have to make sure that your transmission will mate up to the new engine. Another possibility is to put in a Cadillac 472/500 fitted to a TH-400 or 4L80E transmission.
Unless you really like this car, it probably won't be worth financially to do the conversion. You would be better of to find a clean 1991 Cadillac Broughham that already has a 350 motor in it.
Hmm. The shop who I called about replacing the engine had said they'd go with the 4.5, and they knew it was RWD. That makes me not have much faith in their work, if the 4.5 can't even go into this car! Argh. I would love to have a 350 in it but realize it's more work than I could pay for. I think I will follow your advice and start fresh with another year. Thank you. I'll put this car into the papers right away and see what happens. The rust is mostly at the bottom of the doors and can be replaced, so maybe someone will be interested since it has a moonroof, etc. I'm definitely going to look for another one with a moonroof.
Unlike the 4.1 which had a FWD and RWD block, the 4.5 block only came in FWD configuration so I don't know how they thought that they were going to make this engine work.
If you like your body style, 1980 with the 368 was a good year. Also the last couple of years that had a 350 TBI and 4L60E was good as well. However, finding one with a moonroof won't be easy. That was a rare option.
Automobile(s): Cadillac 78 Seville, 78 Coupe de Ville, 92 Sedan de Ville
Re: HT 4100 4.1 motor problems - giving up
I think an Olds 307/350 swap would be the cheapest way out for whoever gets the car. A Chev 305/700r4 would be a worthwhile swap too. I hope somebody fixes the car because I love a Caddy with a moonroof.