Comments: 1-15, 16
HT4100 engine problems.
Overheating.
Engine knocking.
Underpowered.
Cam wear.
Accelerated engine wear.
Rapid oil consumption.
Unfortunately, the HT4100 engine had an aluminum block with cast iron heads. The coefficients of expansion caused most of the bolts to come loose allowing antifreeze to leak into the oil pan. This caused critical engine wear. Porosity problems from GM's die cast process added to the self-destruction of the little engine.
The concept was great, small and powerful. Early on, mechanics began noticing what would be called a "milkshake" appearing at the bottom of HT4100 oil pans. It was a mixture of oil and antifreeze. The lubricating qualities of the oil were reduced to zip and camshafts were ground down to zilch in short order. GM sought to cure the porosity problem by Loctiting the blocks however, unsuccessful. Making matters worse, the transmission was highly problematic.
I did an extensive investigation of the problems that caused the HT4100 failure and the reason for the failed class action against GM for the HT4100. Anyone interested may contact me for my special report on the horrors associated with the HT4100. Contact APNewsletr@aol.com.
Thanks, Ken.
steven@carsurvey.org: Below is an updated text added on 27th May 2003.
Due to the tremendous failure of the HT, there existed a surplus of aluminum blocks in auto wrecking yards. The engines could not be reliably rebuilt and the only worth that they had at the time was the "aluminum" which had an after-market melt-down value. GM sought to buy back many of these cores but was unfortuntely, outbid by its competitors. The blocks were subsequently melted down for industrial application. This caused a tremendous shortfall of blocks known as "float" or in common parlance, rebuildable blocks. Besides the core shortage, the HT with its unique free-standing wet liners and its tedious specifications was extremely difficult to "rebuild."
In the mid 1980's, the national and international demand for HT's was massive. GM thus kicked off a "remanufacturing" campaign and engaged the services of an independent engine remanufacturing concern. Following intensive study of repair, warranty repair data, performance, "hot testing" and other information in connection with the "infant" failures of the HT, GM and the remanufacturing concern forecast a considerable demand for HT's "per day."
Further impacting the remanufacturing campaign was the reality of foundry fallout and porosity problems. Accordingly, in the latter part of the 1980's the engine was placed on "national hold." GM and the independent concern made substantial gains in engineering fixes re: the design and process defects inherent in the HT. The remanufactured model was GM's biggest seller and circa 1989 was costing consumers upwards of $4,000 installed. The "daily", and I enunciate, "daily" demand for the blocks was a whopping 50 engines per day.
Those of you who contend you have seen "good HT's" may very well have purchased a vehicle with the remanufactured block. If the vehicle had the original engine, dollars to donuts the owner was fastidious about changing the oil and may have taken the advice of the savvy mechanics of the time who knew to periodically retorque the bolts in the engine and to check the bottom of the oilpan for the fatal "milkshake" (ethylene-glycol [anti-freeze], water, & gasoline) which was directly responsible for accelerated wear on "all" moving parts from main bearings to worm gears. Essentially, it turned the oil into "spit."
Accordingly, the elegant solution or remedy I am speaking of is to replace the OEM factory engine with the "remanufactured" HT which GM invested $$$$$$$$ in analysis, subsequent testing and re-engineering. But no one knows that because only a handful of people, litigated the matter. Simply replacing the failed HT with another factory manufactured engine would start the vicious cycle all over again. As I argued in my lawsuit, the engine was fatally "unmerchantable."
Gentlemen, this is just the tip of the iceberg. I prepared an extensive analysis of the engine and "ambushed" GM during my video-taped deposition with my findings. That frosted not only GM's expensive lawyers but its former chairman Roger Smith and others. Listen, GM's intention was "pure" in remanufacturing the little engine - it simply just blew it.
Further, no one is aware that the HT was not intended to power the big dreadnoughts, that is the vehicles with high curb weights, it was intended to power the "downsized" models that came out later. However, due to schedule slippage, it had no choice but to put them in the larger models. Gentlemen, that is why the poor weight-to-horsepower ratio and lethargic responsiveness. The fixes they employed were beneath the standards of quality engineering - that is - until the remanufactured unit was made available. The most damaging aspect of the HT was its metal-aluminum construction which caused the engine to expand and contract at different rates, and in connection with the infamous "milkshake" caused an extremely high incidence of infant engine failure.
And again, this is the tip of the iceberg. For those of you who may be in denial or are simply gainsayers, I have the video-taped deposition as well as my point-by-point detailed analysis of all reported and unreported problems associated with the design, dealing with infant failures, recalls, campaigns, service bulletins and so forth.
I really commiserate with the many fixes I see being exchanged and commend everyone on their resourcefulness and creativity with regard to your various approaches on attempting to apply fixes to the engine or chassis. I too loved my 1982 bustleback with its beautiful simulated rag-top, great mileage, and so forth. Unfortunately, I surrendered my vehicle post-litigation and had absolutely no desire to purchase another unit.
So did you win your lawsuit then? only I have never heard of any legal wranglings over the seville, although am well aware of the many problems that plagued the diesel and petrol engines.
I enjoyed reading your take on the HT model. You are the first commenter to actually sound like they know what they are saying when they give a poor review to a car. This is coming from a DIE HARD Cadillac fan.
Although I was a little confused, The HT series does not end with the HT4100 (4.1 letre V8), there was the HT4500 (4.5 letre V8) built in the mid to late 80's and the HT4900 (4.9 letre v8) which was built from 91 to 93 in all cadillac models and was still built untill 96 in some models like the fleetwood and deville.
My question is, are you talking about the HT4100 only or are you talking about the whole HT series? And, What is your take on the HT4900? Which I own, I like it its been a great engine since 1992.
This reply is in two parts.
1) My case against the HT4100 never went to trial as the manufacturer settled in the busy law and motion department hallway of the court.
2) An intense analysis and in-depth research of the problems plagued by the HT4100 from 1982 through 1987 was made in preparation for litigation and with respect to prevailing in Lemon Law, Breach of Warranty, etc. causes of action. There is no other way to engage a large auto manufacturer in court other than by such exhaustive evidentiary labors. That was not done for subsequent HT models and accordingly, your questions cannot be specifically addressed with the same technical command as one has for the HT4100. One trusts you have the resources to best check the merchantability of later HT's out. Don’t think it should be that difficult. Happy surfing and best of luck.
Kin (apnewsletr@aol.com)
I was smiling when I read the comments about the Cadillac 4100. I had an 82 bustle back with that motor and after about 6 months I wondered if GM had made a formal apology for the motor. What a dog, under powered and as I found out with the mechanics, "it was done for" at about 80K miles with terminal cam and crank knock. Cosmetically it was a very nice car and I let a local guy have it for $200, who thought he could make it run again, goooood luck!!!
I just want to thank you Kin for your book on the HT4100. I had no idea it would be so rich with photos, drawings, facts, explanations regarding information breakdown with regard to the design and performance problems of the engine, complaints from owners filed with NHTSA, legal history, problems with the block from dye casting to oil puddles on the the showroom floor; man, stuff I could never have imagined or could find out about on the Internet. I thought it was going to be a few pages of regurgitated stuff I've already heard about, but this is a classic piece of work. There's nothing out there, I mean no where like it. I happen to have a copy of the book "Cadillac - The Heartbreak of America" written in the early 1980's documenting complaints from consumers about their HT4100 problems. That entire book (or pamphlet) sounds so information-challenged compared to yours. In fact it could be used as an "introduction" to yours! Well, I guess it was too early to get into the nitty gritty on that guy. I don't know how you did it. Hey, thanks for answering my questions and suspicions and more.
John A.
Great article. You mentioned that the some of the Seville 4100's got the re-manufactured engines. How can you tell which ones received them? Is there a way to find out? A co-worker of mine is selling one for $800 and he has said that he never had any problems with it. I heard it run and didn't hear any knocks or pings that would alert me to a problem. It has 74K and when I checked the dip-stick, I didn't find any "milkshake" type color on it. I'm on the fence on this one. Need a nudge either way. Thanks for your time.
E.
"Great article. You mentioned that the some of the Seville 4100's got the re-manufactured engines. How can you tell which ones received them? Is there a way to find out? A co-worker of mine is selling one for $800 and he has said that he never had any problems with it. I heard it run and didn't hear any knocks or pings that would alert me to a problem. It has 74K and when I checked the dip-stick, I didn't find any "milkshake" type color on it. I'm on the fence on this one. Need a nudge either way. Thanks for your time."
My advice is that $800 for a running car is a good deal. Buy it. If it lasts for only three months, you're still farther ahead than if you'd bought a new car on payments. Drive it for a year, and you'll have saved thousands of dollars over buying a new or even used car.
Can somebody please post where one of these re-manufactured engines can be bought. I have a A+ garage queen that has fallen victim to the HT4100. To keep the cars value I really need to keep this same engine in the car. I've found a few corner shops that say they can do it, but the references are weak as not many younger mechanics are familiar with this engine. Any leads would really be appreciated, as even the Internet is showing weak leads on this engine that is quickly disappearing. (maybe that's a good thing)
Jeff.
I am interested in buying a 1986 Brougham which I believe uses the HT4100 series. After doing my research and finding your review on the engine, I am not sure. It has 65,000 and looks like its been taken very good care of. Please let me know if the re-manufactured engines were used in this model.Thanks.
I have not experienced the well-publicized maladies of the HT series engine. In fact, my mom bought a new 85 Eldorado 4.1 and to date it has a little over 400,000 miles on it, with the only failure being the distributor drive gear. Indeed, being a 20 plus year ASE Advanced-level Master Technician and Cadillac owner/driver/mechanic, I cannot recall and HT base engine failure coming my way. My most recent acquisition is an 85 De ville with 197,000 miles on an original documented engine. Compression reads at 180F an average of 155 psi with a variation of no more than 10 psi; idle oil pressure of 22 psi at 195F. These findings are very respectable even for a Toyota 2.2 with 50,000 miles. The 4.5/4.9 seems to be the most desirable units, if not simply because they embody superior performance. Overall, like with any used equipment or automobile, an ounce of prudence in the pre-inspection is worth the investment in time and money. Of course, I am a lifelong gearhead that can find affection with the most hated internal combustion outcasts!
Hi HT4100 inquirers:
According to a book I purchased entitled, "HT4100 4.1 Liter Digital Fuel Injection Metal-Aluminum V8 Gasoline Engine - Cadillac's Miscarriage of the Millennium" (I see that John, in the above message dated 15th Aug 2006, 17:36 also purchased) the re-manufactured HT4100 engine was re-tooled by a major engine rebuilder in the south who working with GM's design and field engineers and others performing hot and cold testing, pressure testing and so forth to replicate the conditions that caused the engine to self-destruct. From this, improvements were made, gasketing technology, revised maintenance procedures, revised coolant treatment and a host of other engineering patches to make the engine as reliable as was possible at the time.
However, those engines have all been sold. What you get nowadays is a pig in a poke rebuilt short/long block. There is a reason why mechanics don't want to work on the engine - - there are just too many tedious specifications and the thing is about as tight as a washing machine. The vibrations actually cause it to "undo." That is why retorquing is recommended every few years.
There's a fella that goes by the handle of HT4100Whiz who also has some sage advice on HT's. A copy of his blog entry appears as follows:
HT4100 Whiz08-28-2006, 02:57 PM.
"By all means, you should swap out the HT4100 which is absolutely the greatest single disaster in GM's engineering history. It started out with good intentions, but went to hell in a handbasket due, in part, to prematurely releasing it. That engine was fatally unmerchantable out of the gate. The 350 swap out seems to be working very well. Go to:
http://www.eldocountry.com/eldo/swap.html for the details.
It's no piece of cake, but if you want to try to hold on to your Caddy, check it out.
The major problem with the HT4100 is glycol-antifreeze intrusion, a condition for which the HT4100 is both infamous and notorious. In addition, the engine is a bi-metal engine (aluminum and iron) which vibrate at different rates and cause the engine to virtually vibrate itself loose. This, in conjunction with the antifreeze results in a self-destructing vicious cycle (some fancy schmancy physics known as variable "coefficients of expansion.") There were also problems with the engine's gasketing being able to cope with all the block and manifold movement. The antifreeze wipes out the lubricating properties of motor oil which accelerates wear and tear on all moving parts including the cam, worm-gears, and so forth.
There are a few things you can do to decrease the above self-destructing scenario, 1) under absolutely no conditions, do not wait for 3,000 miles to change your oil! - do it a lot earlier; and 2) use GM Part No. 3634621, coolant pellets, which act as sealants to forestall antifreeze intrusion. Use the recommended dosage, but no more because they have been known to seal other voids such as heater and radiator cores. Change the water at least annually.
P.S. There is an incredible, almost completely unknown book entitled, "The HT4100 4.1 Liter Digital Fuel Injection Metal-Aluminum V8 Gasoline Engine - Cadillac's Miscarriage of the Millenium." The book contains an incredible wealth of information on the design, manufacturing and engineering problems/defects of the engine. It is an eye-opener and a rare book and is somewhat difficult to obtain. If you want to try to obtain a copy, the distributor can be reached at APNEWSLETR@aol.com.
Sincerely,
HT4100 Whiz!
APNEWSLETR@aol.com.
Now I know why my beautiful 81 bustle back died, here in the UK it was much admired that was way back in 94,now I have a low miler 5.7 diesel which I hope will last longer, i must say its damn noisy on tickover, but hopefully when its recommissioned, and back on the road we will not hear it? its been in hibernation for ten years.
I am so thankful for finding your article. I have been actively shopping for a 80-85 Seville. I knew to avoid the V8-6-4 and the dreaded diesel, but I had no idea the HT4100 was as bad as the others. It seems my only choice is a 1980 model with the 6.0 liter engine. Do you have any comments on that engine? Of course these are rare and anyone who has one probably knows they have a gem and will demand top dollar, but, hey an expensive car that runs is better than a 4000 pound doorstop. Thanks, Randy Hall BRHero@msn.com.
20th Jul 2007, 14:43
Now I know why my beautiful 81 bustle back died. Here in the UK it was much admired; that was way back in 94, now I have a low miler 5.7 diesel, which I hope will last longer. I must say it's damn noisy on tickover, but hopefully when it's recommissioned and back on the road, we will not hear it? It's been in hibernation for ten years.
I don't believe your 81 had the HT4100 engine. That was the year of the other notorious engine, the V 8-6-4, which had its own problems.
My 1982 Sedan Deville had a 4100 in it and it died on me too. It was left to my by my late grandfather, so there was no way in the world I was going to let it go. I called and called and no place would replace the engine with anything, but another HT4100. I finaly came across http://www.cad500parts.com/ and I called them up. I was toying with the idea of putting a 500 from a early 70s model El Dorado so I could keep the engine in Cadillac family and finally give 'Ceasar' the power he deserves. When I mentioned this to them they listed everything I would need instantly on the phone (motor mounts, custom oil pan that they sell, etc). I went with them and now my car has its life back. Keep in mind my project wasnt cheap, but I was willing to pay for it since this car will be with me for the rest of my life (its the special occasion car of the family). Total cost of the swap was about $12k. This in includes my flight from Tucson to LA to pick up the donor car, gas to drive it back to Tucson and then to Albuquerque, Buying the donor car, Gas for my friend to tow the Deville from Tucson up to Albuquerque and his return, My flight to Albuquerque to pick up the car, The Turbo 400 transmission, the cam kit and other engine upgrades.
They do sell swap kits (like the oil pan to clear a cross member correctly) and I would recommend them to anyone. The only problem I had with the swap was my oil filter had a hole punched in it from the sway bar from making a tight turn. The oil filter was not in that area with the original engine. I purchased a remote mount kit from Don's Hotrod shop in Tucson and moved the filter up under my hood, which makes it very easy to change my filter now.