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1991 Buick Reatta engine failure


PaulP117

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Hello again! It’s been a while since I last was around the reatta forums, and unfortunately I come back with sad news. I’ve been keeping it alive and daily driving it for a while and it was running fairly well until I started having poor oil pressure performance at idle mostly, replaced the sending unit and still had the same readings but tested it manually and had decent enough oil pressure so I kept driving it (probably shouldn’t have). After a few weeks, while driving it the engine dropped out running hard and then stalling after a few seconds of running. Long story short I got the car to a garage and started diagnosing the issue. I was hoping it was something others have faced here on running poorly but unfortunately not the case. Good spark, good fuel pressure, good compression in 1-2-3-4 but garbage compression in cylinders 5 and 6. I had 0psi in cylinder 5, and 50-60 psi in cylinder 6. While getting the readings again to be certain, something I didn’t notice at first even though I had the valve covers off the first time was that while turning over the engine to do the compression test the rockers were dead stiff! After the basic tests got me there, we got a camera into a passage in the head down to where you could see the camshaft closest cylinder 5/6 and then had someone spin the balancer. Sure enough that thing didn’t move an inch. Surprisingly I couldn’t find anything about the camshaft snapping on any other reattas or other 3800s. I do hope nothing like this happens to anyone else, but if it does I do hope my info dump here helps as proof you should always test your basics on your engine diagnosis if all else fails. even on these cars with all their finicky other failures we’ve all faced. I’ll drop some pictures and updates when I get it torn apart. Last thing I will say is that even if it’s gonna hurt the wallet i will keep this Reatta alive!

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Cam bearing 2 got torn up when the camshaft broke. I can see where a chunk hit one of the crankshaft ears but nothing severe. And no damage to the block itself or the area the cam bearing would be pressed into. 

IMG_4837.jpeg

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How many miles at the time of failure? Unusual problem to be sure. The 3800 is a non interference engine so there shouldn't be collateral damage. Thanks for posting the details.

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No personal experience but a previous knowledgeable engine expert, Pagette, mentioned what he called dropped cam bearings on more than one occasion which caused lower oil pressure. No mention of breaking the camshaft but ???  Kind of a chicken and egg question

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Posted (edited)

Failed right around 193,000 miles. And yeah it definitely is a weird failure based on all I’ve read  about the 3800. But If I had to put my money on a guess, I’d think the cam bearing dropped out and either wedged the camshaft in such a way it cause the initial break or the lack of oil pressure on that side of the engine making it work harder on those last two cylinders just slowly weakened the cam until it broke from the stress. In a way I’m glad for it, now I have an excuse to the more serious maintenance I’ve been putting off. timing chain, front cover leaks and oil pan leaks and the rear head gasket leaking. If I didn’t know better I’d say low oil could’ve cause the failure but I always kept a gallon in the trunk and made sure it always had a good level 

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Thanks for letting us know. Your conjecture sounds much like what our dear departed Pagette has said. Good luck and I hope all the associated parts check out👍

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Update: I had my machine shop guy take a look at the block to quote installing new cam bearings and he noticed something I missed. The surface for the cam bearing does have a good chunk sliced out of it where the camshaft broke. The cost of machining the block and needing to install larger cam bearings, etc is just not worth it, I might as well buy a reman engine which I am gonna probably do. would anyone know a better place to find a NOS or reman engine? The only site I can find that offers the L 3800 still is https://shop.powertrainproducts.net/product/1990-1992-gm-3800/?srsltid=AfmBOorIpA5TXfrPc0-m7yULDucEOf3IE4b6nvGoJebkfS8L40nhn22DskU

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For my 2 cents, it would be far easier to find a recycling yard with a compatible motor that also installs engines.  I'm sure a relatively low mileage example can be readily found for few shekels.  A friend had a beautiful 93 type S Jaguar V8 that he could not get running.  About to junk when I took it for $300.  Diagnosis showed the engine was toast.  Seemed shame to discard a car with beautiful exterior and interiors.  Found a yard that had the V8 and did installations.  The bill was $1300 plus about $300 for parts I had them replace.  Sold the car for $3900 [hated to see it go because it was fast, smooth, extremely comfortable, but like so many Jags, prone to minor issues that run up big bills].

I thought the cam bearing issue was confined to the 1990 block casting?  I had a 90 with the sunroof and 177,000 miles.  Ran fine.  Thought I'd treat the old girl to some Slick50 as a reward for serving so well.  The additive was slippery enough to cause the engine to spit a cam bearing into the pan.  Oil pressure was next to -0- at idle and maybe 30psi at higher rpms.  Ran for another 19k before giving up.  I find the Buick V6 3.8L motors to be unexciting but incredibly forgiving.

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I hope you can find a good replacement engine. The sad fact is the Series 1 engines have been out of production for over 25 years so the salvage yard supply is dwindling although a rebuilder may be good to go. I remember years ago the yard guys said they couldn't give away the older LN3's because they were so reliable🙃 Rebuilding your own engine is getting harder and more expensive, although the expense for non-SBC has always been high. Replacing cam and bearings, no big deal, but once into machine work, the rabbit hole gets deeper fast☹️

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3 hours ago, wufibug said:

For my 2 cents, it would be far easier to find a recycling yard with a compatible motor that also installs engines.  I'm sure a relatively low mileage example can be readily found for few shekels.  A friend had a beautiful 93 type S Jaguar V8 that he could not get running.  About to junk when I took it for $300.  Diagnosis showed the engine was toast.  Seemed shame to discard a car with beautiful exterior and interiors.  Found a yard that had the V8 and did installations.  The bill was $1300 plus about $300 for parts I had them replace.  Sold the car for $3900 [hated to see it go because it was fast, smooth, extremely comfortable, but like so many Jags, prone to minor issues that run up big bills].

I thought the cam bearing issue was confined to the 1990 block casting?  I had a 90 with the sunroof and 177,000 miles.  Ran fine.  Thought I'd treat the old girl to some Slick50 as a reward for serving so well.  The additive was slippery enough to cause the engine to spit a cam bearing into the pan.  Oil pressure was next to -0- at idle and maybe 30psi at higher rpms.  Ran for another 19k before giving up.  I find the Buick V6 3.8L motors to be unexciting but incredibly forgiving.

 

  Color me CONFUSED!     How does slippery cause a bearing failure?

 

  Ben

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Posted (edited)

It doesn’t seem like jasper has any 3800’s. And that site I previously linked said they have none in stock and no ETA on it. And I’m running out of places to look when it comes to getting the same 3800. Does anyone know what the difference is between the 91 reattas engine and the 1995 - 1996 Buick lesabre’s engine? Besides the different colors intake and cover. Is there any reason not to think that block should fit my year model 3800, and its parts? Such as the intake and various brackets and bell housing bolts 

 

This is one I found that seems available which is why I ask.

https://reman-engine.com/product/3-8l-v6-engine-for-95-96-buick-lesabre-park-avenue-regal-riviera-chevrolet-lumina-van-oldsmobile-88-98-lss-pontiac-bonneville-fwd?title=DB55&delivery=Commercial&coreVariantId=core-waiver

Edited by PaulP117
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Ben, from what I understand the 90 casting was just a hair off, just enough so the anti-friction elements in Slick 50, supposedly  PTFE, allowed a pressed in bearing to come out of its casting.  I found it mutilated in the oil pan.

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14 hours ago, PaulP117 said:

It doesn’t seem like jasper has any 3800’s. And that site I previously linked said they have none in stock and no ETA on it. And I’m running out of places to look when it comes to getting the same 3800. Does anyone know what the difference is between the 91 reattas engine and the 1995 - 1996 Buick lesabre’s engine? Besides the different colors intake and cover. Is there any reason not to think that block should fit my year model 3800, and its parts? Such as the intake and various brackets and bell housing bolts 

 

This is one I found that seems available which is why I ask.

https://reman-engine.com/product/3-8l-v6-engine-for-95-96-buick-lesabre-park-avenue-regal-riviera-chevrolet-lumina-van-oldsmobile-88-98-lss-pontiac-bonneville-fwd?title=DB55&delivery=Commercial&coreVariantId=core-waiver

That is a Series 2 engine and parts cannot me mixed and matched with the existing engine. The Series 2 came out in 1995 in the naturally aspirated version. The supercharged variant of the Series 2 arrived in 1996. 3800's through 1994 should work. That said, a complete Series 2 engine could be substituted with some adapting.

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The handful of places that still have the series 1 still listed on their websites all called me back and all of them have have said the same thing. No inventory or ETA on the engine. While unfortunately I was hoping to drop a new engine inside the car it’s just not easy to find one anymore. However some good news, I was able to order a used one with low ish miles (60k) off of eBay from a 1991 Buick Regal donor car

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Youngs Auto Parts in Adrian Michigan had one with 17,000 miles on it. Price was $525.00. It was on Car-part. When I went to get one from a yard I used a hitch mounted hauler. That way no grease or fluids in the Enclave. Worked for that and the transmission [two different yards] when I did mine back in 2017. 

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3 years ago the meet was in a Chicago suburb and one of the Reatta member from Wichita KS  drove his car and had the same failure. 

it was the first I had heard of a cam breaking.     He found a low mileage replacement engine I think he said for $300 and had it installed. 

I did not read all of the above but I would think the only reason it would do that is a cam bearing seizing (lack of lube?)   Pretty sure his engine was under 100K

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  • 2 weeks later...

It was a successful week! It’s back up and running! And running pretty damn good. I put new timing chains and gaskets all around on the new to me engine before dropping it in and I’m glad I did. The old cam magnet was toast so it felt good to do it the right way. The difference in power from what it used to be and overall smoothness of the car is night and day. Just need to get a new front windshield and wheel center caps (ouch expensive) and I think it’ll actually be worth showing off now and again. 

IMG_4940.jpeg

IMG_4943.jpeg

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I recently did a breakdown of the 1991 Polo Green cars. 

Since this car is that color,   I will attach the information....   there was a total of 121 Polo Green coupes built and it was a 1991 only color.  

There are 5 green cars that would be 1 of 1 because of the options, and no pin stripe.

Example... only 1 was made with black side molding, 16 way seat option, sunroof and no pinstripe (901432) 

polo green.jpg

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My wife's Allante' is Polo Green; it's a handsome color.  In low light it looks almost black, but in bright sun the metallic really pops.  ;)

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