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MarkV

GM 3.8 and 3800

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So, what is the difference? My friend is looking at a 1986 Olds 98 Regency with 140,000 in very good condition, that an older guy in his late 60's owns, with great paint and interior and has been properly maintained, it has a salvage title, because the fender was backed into a few years ago (no frame damage) and the insurance decided to 'total' rather than fix, but, he kept it and fixed it and it looks great, no other damage present, and it looks like new, his parents bought it new. We are also wondering how many more miles it has left in it? Also, what is the difference between this engine and the 3800 in my 1991 Lesabre? How are the 98 Regencys? I dont know much about them!

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One of the best V-6 engines General Motors built, in my opinion. I had about 250,000 on my Pontiac. It was very quick, and very strong on the highway, while providing excellent gas mileage.

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So what is the difference between the 3.8 in 86 and the 3800 in 88?

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3.8 L = 3800 cc

not sure of the yearly nuances over 2 years but I would GUESS they are nearly identical

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I'm pretty sure the biggest difference is that the 3800 added power and the balance shaft which eliminated the lumpiness at idle that is characteristic of 90 degree V6's.

More here:

Buick V6 engine - Wikipedia, the free encyclopedia

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No, they offset ground the crank to smooth it out. That was the problem with all bent V-6 engine until they started grinding them offset.;)

Don

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is there any difference with reliability or longevity? How long do they last? I have read reviews with some people saying that theirs has 500 k miles.

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is there any difference with reliability or longevity? How long do they last? I have read reviews with some people saying that theirs has 500 k miles.

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Wes, they last a very long time. Buick did have some problems with the very early offset ground cast cranks. The forged cranks that I see in T/types and Grand Nationals are very robust, and these turbo V-6 coupes are running in the high 9 and low 10 second quarter mile in a mid-size coupe are a sight to see, carrying their front wheels off the ground for all of first gear. I still prefer a un-bent six (I) for smoothness and reliability of seven main bearings. I mean a "I" six is inherently balanced just by it's nature.

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depends, there is a 3800, and a 3800 series 2 and a series 3 as well, the series 1 was a good motor,, the series 2 has , or can have problems with the Plastic intake melting from the EGR tube into the coolent passages near the throttle, and flooding the engine without warning full of engine coolent,, the series 3 when to a cast alum intake again,,

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depends, there is a 3800, and a 3800 series 2 and a series 3 as well, the series 1 was a good motor,, the series 2 has , or can have problems with the Plastic intake melting from the EGR tube into the coolent passages near the throttle, and flooding the engine without warning full of engine coolent,, the series 3 when to a cast alum intake again,,

There are far more differences than that. The 3.8L version is the old 231 cu in Buick V6. This motor has the B-O-P trans bellhousing bolt pattern and the uneven exhaust port spacing that looks like 3/4 of the Buick V8 spacing. This motor has the even fire crank.

Starting with the 3800 Series 2 motors, the block and heads were completely redesigned. The bellhousing was changed to the narrow "GM Metric" pattern first seen on the 2.8L Chevy 60 degree V6. The heads were changed to have equally spaced ports. There is no provision for a distributor. The oil pump is a gearrotor design on the end of the crank. The intake was changed to plastic. Balance shafts were incorporated.

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I curently have three vehicles with the 3800 engines. The engines are absolutely bulletproof. Plastic intakes, as noted, had some problems. Some crank sensor issues, but nothing to worry about. The mileage on the '92 Trans Sport is 266k, the '94 Trans sport, 225k, and the '88 Reatta 153k. The earlier 3.8 engine fared equally as well, IMHO. David.

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The earlier style 3.8 had issues with the timing chain. If it failed the valves would contact the pistons. This would damage the valve train and possibly the pistons and cylinders. If the timing chain is replaced as a maintenance item the engine will perform well for many miles.

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"plastic intakes had some problems?" GM specified incompatible seals and coolant, and cost-cut out the locating inserts. They were so bad an aftermarket company could afford to tool up to supply replacements. Sorry, not a 3.8 fan.

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But that is not until the Series III if memory serves, I am speaking of the 1985-1987 and 1988-1992 Versions

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I've broken the timing chain on on an '89 3800, that engine was non-interferance, don't know that it would differ on other years.

....and there are two 3800s '88-90 (pre-series one) and Series One which ran from '91-95. I can say the series one was prone to head gasket failure which was remedied during the run, still was a common problem in '93, (two separate failures on '93s in my history) not sure precisely when the revised gasket debuted.

In any case in my experience the pre- and Series One are very good, reliable and long-lived powerplants.

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All gm's V6's had problems with the intake to heads gasket ? a chunk of plastic with rubber donuts built in,, 2.8's, 3100, 3400 and the 3.8s, which where not bad if it leaked outwards,, and you caught it in time.. i had the 3800 in my 92 bonniville and i never had any problem with it,, so i bought an 97 Olds with a 3800 and i have put 2 motors in it so far and only have a 163,000 miles on the car from the engine hydro locking on the highway, when the plastic intake melts through from the EGR pipe..

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I had an 88 Buick Electra with the 3800, I put 157,000 miles on it with no major mechanical problems. I did have to replace the cam sensor which was fairly expensive. The biggest problem on that car was the alternator, had to replace it about every 30,000 miles. Turned out that its design was faulty and did not allow proper cooling so it burned up, this was so common on the 80s GM cars that the auto parts stores would not offer their lifetime warranty on those alternators.

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My grandparents had an '88 Olds 98 with the 3.8 or 3800 engine in it. Was traded in with over 200k on it for a 98 olds 88 with the 3800. The car currently has 80k on it and I just tuned it up and had to replace an injector. Other than that its been troublefree.

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Wow thats great! We picked up the car 2 days ago and so far so good!

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