1982 Cadillac HT4100 Engine Story Manufacturer Promotional Video
A new lighter V8 engine was rushed into production for 1982, the HT-4100 (option code LT8). It was a 4100 cc V8, designed for rear-wheel-drive and longitudinal front-wheel-drive applications sharing the same transmission bellhousing pattern as Buick, Oldsmobile, Chevy, and Pontiac rear- and front-wheel drivetrains for 2.5 L 4-cylinder and 2.8, 3.1, and 3.3 L V6. A transverse front-wheel-drive version was originally slated for 1983 and a new line of downsized Cadillac sedans, however, delays in the downsizing program shared with Buick and Oldsmobile postponed the introduction of those models until 1985. The HT4100 was prone to failure of the intake manifold gasket due to scrubbing of the bi-metal interface, aluminum oil pump failure, cam bearing displacement, weak aluminum block castings and bolts pulling the aluminum threads from the block. It may not have been the most successful engine to sit under the hood of a Cadillac, but potential buyers were no more satisfied with the other two engines available at the time, the V8-6-4 and the Oldsmobile 5.7 L Diesel. Reliability issues soiled the reputation of the HT4100. As a result, the V8 Oldsmobile gas engines were a popular and straightforward conversion.
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BEST CADILLAC ENGINE EVERMADE OF THE 80S AND EARLY 90S ERA 4.1L,4.5L,4.9L AND 4.6L 32 VALVE NORTHSTAR ENGINE V8 MOTOR
I wouldn’t call this the best!
This engine and the Northstars are junk! 4.5 and 4.9 Cadillac engines were good, however.
As were the Allanté 4.1 and 4.5, both of which were based on the reinforced block of the Cadillac 4.5. No Allanté was ever built with the HT4100 motor; the just used cast iron cylinder liners that gave them the same 4.1 liter displacement.
The Northstar V8 and the HT 4.5/4.9L engines were excellent. The 4.1 were good but more after the 1985 model year.
(I’m a huge Cadillac fan by the way).
The Northstar V8 was a great high performance engine and one of the longest in production put into many Cadillac’s and other GM cars. They have stayed around almost 20 years for a reason!
surely not the 4.1, but the later 4.5 and 4.9 variations were pretty decent designs
Seems they did every test except a durability test to see how long it would last. The best Cadillac built engine of the 80’s was the 6.0.
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In my opinion the early 4.1 (82-85) was an “OK” engine, but had no place being in the full size Fleetwood and Deville. The bigger cars are where what killed the 4.1’s reputation, but the were easily fit for the lighter Seville and Eldorado. They should have improved and kept the V8-6-4 until they had a better engine for the Brougham, it is too bad they didn’t.
The original plan was pretty much what you say: Use the v-864 for the big RWD cars and the 4100 for the smaller FWD cars. Unfortunately, the software/hardware for the variable displacement apparatus was not up to the job and to keep selling cars pending the arrival of the seriously delayed FWD cars, they rushed the smaller HT4100 into production and used this 120hp engine to pull Fleetwoods. The engine failed at every point possible under the heavy loads. It was marginally improved in ’85, but the biggest change was the lighter sedans that were finally introduced.