HT4100 Review

[@markman7]

Friend had a 1984 Seville who rebuilt the 4100 in it and put over 200k on the car afterward until its crank broke. He was a Cadillac Dealer mechanic, and knew the engine. He later rebuilt the 2000 Northstar I still drive today.

[@mindyholiday8391]

so much fun ! do more content. great team ! LOL you saved me from buying an 84 same car . Thank U

[@shanelucas3159]

Did the water pump on my 84 Fleetwood HT4100, now having to replace intake manifold gasket, after already putting the engine back together! It is a nightmare!! I feel like I've taken literally everything off the engine block except the exhaust manifolds and cylinder heads.

[@derekcercena2273]

This is awesome, I can definitely relate- mine is a 1984 Cadillac Seville Slantback with the same 4100hd

[@giltracy505]

Makes a good couch! Had one of these beauties,kept a bottle of aspirin in the glove box.

[@ruxrox]

Keep it smooth and slow. An elegant vehicle sets the tone. The party comes with the car.

[@chuckmaddison2924]

Don't worry, Australia had a big stuff up as well . The P76 almost Impala size, standard 2.6 6 cylinder you could walk around and a 4.4 all alloy V8 which had same weight as the 6. It didn't last.

[@Smilyface509]

I did the water pump without taking the power steering pulley, just a lot of sweating while using a wrench from underneath on those 2 bolts behind the pulley. Not a fun job at all and I had to do it all again because the thermostat was bad and the thermostat housing goes on with the water pump at the same time! 😂 But now it runs and drives with no leaks… what a pain.

[@ephraimfink9010]

The lamenting of the HT4100 was overblown BS. We had an 82 or 83 Eldorado Touring Coupe and an 85 Eldorado convertible and if maintained the engine was reliable and smooth. We pulled a boat with the 85 for crying out loud, plenty of torque.

[@johnrand93]

I was given for my HS graduation, an 1983 Biarritz and I drove that car until 1990 and NEVER once had to take it in for a single thing, except regular maintenance. I currently own a 6K mile 100 % original 83 Biarritz and a 40K mile Seville and I've never had a single issue with either. Mine both run like a swiss watch and are very quick for the size of the car. I think the big '"C" body cars were just to heavy for the engine but the Eldo and Seville, they are perfect. I LOVE mine and like them better than my 16K Eldorado Biarritz with the 350 EFI. It all comes down to how they have been maintained and driven.

[@Dannyboy-nj4wh]

Keep the GM pellets in the cooling system and regular maintenance done and DONT DOG It and its reliable

[@LowEnd31st]

Not really. These were truly junk. Anything still running today prob had the engine replaced under warranty with the “upgraded” one. My 85 eldo seized up and it was a good wrench replacement

[@photonphil873]

@@LowEnd31st There is no way around it!!!!! They were very PROBLIMATIC! The radiator was almost entirely plugged. Aluminum heads on cast iron block was just the tip of the iceberg. The interior, de eleganz, and the tilt wheel were awsome.

[@empireOfLove2]

you should tell that to the mechanics that had to throw out cubic yards of those engines daily in the 80s.

[@dwz55555]

I had decent luck with 4100's i actually had one with 4.5 cylinder sleeves, milled heads, 6.0 tbi dual exhaust with 3.36 gears. The thing felt like a 350 from that time period.

[@brickkkkk2gr]

PLEASE post updates of your build! I'd love to see what you're doing to yours

[@barnycanuck6234]

84-85 Caddys were nice to look at, how tuff would it be to throw a different motor in them?

[@empireOfLove2]

it's not bad, they use the metric BOP bolt pattern on the HT4100 and you can put most Olds/Buick engines in them, still not fast but won't be hell to work on. careful if you get an Eldorado, they are longitudinal front wheel drive, and require a custom oil pan/block mount to clear the axle shafts and transmission, much harder to swap unless you get an engine out of a Toronado or Riviera of the era.

[@TheLolo919]

snatch the boat anchor out and put a small block 350 and a 350 trans Shazam

[@matthewcaughey8898]

For those defending the HT-4100 here’s a few specs with other engines of the era. Toyotas 22RE was a 2.2 liter 4 cylinder SOHC truck motor. It kicked out around 116 horsepower which is not a far cry from an engine literally twice its size. Jeeps famous 4.0 high output inline 6 puts out 190 horsepower which is 55 more horses from nearby the same size motor . Even fords 302 was more potent and the GM 305 High output in the camero would have been a better choice to move a big full sized barge. A plain ole 350 or 5.7 crate motor and a TH-350 would make a rock solid combo to move that tank and at least help it get out of its own way on the highway. 135 horsepower is what some 3 cylinder engines make these days

[@joseornelas7616]

Where is distributor hold down bolt located?

[@geneo317]

I have a 1984 Coupe. Changing out the water pump and crankshaft seal. What a pain in the ass. Would love to throw in a Oldsmobile engine.

[@matthewcaughey8898]

A plain ole crate 350 with caprice engine mounts will drop right in there. If you can snag the 700R4 that comes on the interceptor models like I did. Everything bolts right on. Though hot rod TV showed even a few basic parts on a GM 305 could generate over 250 ft pounds of torque and 300 plus horsepower

[@photonphil873]

That is really good info!!!! Thank You!

[@ДмитрийМальцев-и6п]

can put a small block?

[@isfeldt34]

I was just watching a video about this particular engine debacle. Called this was the worst decision that GM could've made, rare classic cars and automotive history. There's also an in-depth video on the HT 4100, how to keep yours running. Not really much high technology. lol if the Oldsmobile diesel wasn't bad enough, the 5.7 L.

[@rushflare8208]

more videos from you guys!!

[@jeffshadow2407]

Is your new address 4100 Cadillac Way?

[@michaelhatcher5264]

GM body by Fisher Engine by Metal

[@djnmemphis10]

I have an 84 cadillac biarritz. What engine can I swap? Thanks. Do I need to change the transmission too?

[@Beechboy68]

If the engine so bad... why is it still driving around 40 years later? That's what i thought

[@MarvinThiessen]

The Feds cowered GM, Caddys built after '80 were mostly junk. Heavy cars with undersized engines. The '79-'85 Eldorado series is a great design except for ridiculous plastic bumper fillers and unnecessary Landau tops. '79 and '80 Eldorado's were the best, both years have a 350 Olds V-8 engine. Nice looking GS dog.

[@photonphil873]

Thank You! Aggie the GSD is an absolute love!

[@pjimmbojimmbo1990]

Plastic Fender Wells won't Rust

[@ruxrox]

Sad to say, I have 2... that is a Sedan Deville. You have one of the very last Traditional Themed Deville made! If not its an 84.

[@craigjorgensen4637]

The Cadillac Dealer mechanics just hated these!

[@kbanks827]

I have a neighbor selling his 1980 Cadillac brougham from $300 because no one wants to buy all it needs is a battery alternator and carburetor to run but those ht-4100 problems I don’t want

[@markschlotter1282]

I had a 82 seville with a 4100 and it was junk, everything that could go wrong did.

[@BigCaddydaddy84]

I must be a glutton for punishment because I have had several of these...smh. That 4100 is a pain. I'm gonna swap my 84 coupe with an ls and be done with it.

[@MrMitokiller]

Maybe a 4.5 or 4.9 thise are great

[@BigCaddydaddy84]

@@MrMitokiller Never had a problem with the 4.9. It was a runner in my 95 deville

[@Clf5796]

4.9 is a trash engine, too. Once you get over 140k miles, the rod and main bearings start to get louder and knock. The powersteering pumps goes out with the ac compressor. You have to change the distributor cap and button when you change your plugs, too.

[@neilouellette3004]

Back in 1985-86 I bought a gorgeous 30,000 mile 1983 Fleetwood Brougham d'Elegance Coupe w/the HT 4100. That motor was junk. Broke down so many times. Hook & Tow 4.1 Worst engine to come out of Detroit. Got rid of that car about 6 months later. Went to Lincoln and never bought a Caddy again.

[@chrislemaster2695]

The old Hook & Tow 4100 just as bad as the First generation Oldsmobile 350 Diesel 5.7 block. In 1982 Gm got the 5.7L DX Diesel block right but the buying public wasn't forgiving. CAFE id Corporate Average Fuel Economy which dated back to 1978 which led to the production of the Diesel 350 block 1 generation. After 1986 these came with the Oldsmobile 307CID V-8 as standard.

[@saganich74]

Better call the HOOK AND TOW

[@Dannyboy-nj4wh]

They can be reliable just keep the GM/AC Delco cooling tablets kn the cooling system and regular maintenance and they are good to go just dont dog em

[@LowEnd31st]

It’s a lot more than that…

[@Beechboy68]

​@@LowEnd31st for you maybe.

[@merc-ni7hy]

if you want it reliable,,thro a ford 390 or 460 in it

[@pjimmbojimmbo1990]

For GM's Flagship Line, Cadillac has made most of GM's Worst Engines. The 8-6-4, the 4.1 HT, the Northstar...

[@ErinMalczewski]

the tbi system is great on latter models. Why not keep the digital fuel system and swap a 5.0. you will use less gas, have close to zero emmissions and it will be a lot less work. Use the the same cam profile as it's a roller. Chevy power. kzbin.info/www/bejne/gYumk4OvqsSthcU

[@bulletboy4288]

That engine was so bad it had recalls in England, they didn't even sell any here 😂.

[@patrickmcgoldrick8234]

The Roger Smith years were very bad for GM,bad quality,X body cars, weak transmission,they were like gate way cars for permanent Toyota owners and future buyers. In the eighties Ford products were considered by Consumer Reports to be the best of the americans cars,and thats not saying much when you consider Chysler front wheel drives,and for the most part GMs troubled field of lemons.

[@chrislemaster2695]

I would pull this turd of an engine out and bolt a Oldsmobile 307 CID or Chevrolet 305 or 350 into it

[@adamturner8634]

I think you should put a ford motor in it lol

[@photonphil873]

I know!!! I was really thinking about a 460!!!

[@adamturner8634]

@@photonphil873 good motor

[@jayson657]

I know government CAFE standards basically limited passenger cars to 5.0 V8’s or smaller to meet the mpg requirements in the 80’s but this undersized, underpowered hunk of junk really tarnished Cadillac’s reputation. Cadillac can almost be forgiven for the failed 1981 V8-6-4 engine. At least cylinder deactivation was a creative attempt to hold onto the cast iron big block 368. Instead of this HT 4100 Abortion Cadillac should have been putting their Digital Fuel Injection technology on to the otherwise carbureted Chevy 305’s and discreetly placing them into their cars with maybe a dual exhaust system w/ resonators an oil cooler, anything to give Cadillac buyers some value for their money over the rest of the GM line up.

[@davidtillwach5542]

GM 8-6-4 V8 Engine was a flop of a motor .I had a 1987 El Dorado and that engine was a 4.1 L engine smoked like the Dickens . I wasn't pleased with other than that . It was front wheel drive

[@Ram14250]

Beautiful car before GM ruined them! Engine was a boat anchor! I drove my boss's 1982 Deville 4.1L and it was a dog! when I was 18years old. I thought the car was pretty nice but ... 0-60 in 18-20 seconds. I know it wasn't made for performance but a far cry from what Cadillac offered in the past. Shame. the 96's with the Chevy LT 350's were much better but that was a chevy engine and a less attractive body. GM was slowly killing their divisions who once competed with each other to make better products. GM is dead now.

[@ponchoman49]

Nonsense. I proper running 4100 in the full sized cars should run a 13 second 0-60 time if in proper tune. If your 4100 is running 18-20 seconds its either way out of tune, has a plugged catalytic converter or the cam lobes are wiped out from antifreeze intrusion.

[@cadillacnan]

13 seconds to 60??? That's just plain awful..

[@cadillacnan]

Had a 69 Buick that did 70 in 9..needle blew right by 60..heavier car too