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questions about the 3800 motor


1991luminaeuro3.1

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I might be getting a grand prix soon and I was wondering if there is any common issues with 3800? I don't know anything about them and how about the transmission?

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The upper intake and the coolant elbow are the two main ones... The upper intake manifold is made of plastic on the Series II 3800s (which the gen GP you are looking at has), and the stovepipe from the egr warps the plastic and causes and internal coolant leak, which can hydrolock the motor. If you take the engine cover off (the grey plastic that says 3800), and look at the manifold, you will see a date stamped in the upper right hand corner.. It will look like clocks, but the hands will point to the numbers corresponding with the date. If it is close to the year of the car, then you will want to replace it at some point before it does any damage. If it is much newer than the date of the car, then you should be good. Most people also do the LIM gaskets on this motor while it is torn down, because this motor will sometimes have LIM issues as well (although not like the 3100/3400).. They sell improved upper intake manifolds online that fix the issue, so it's really not a big deal..

 

The coolant elbow is something you must take off to do the upper intake and LIMs on this engine.. It is a brittle plastic piece that is a common leak point, and almost always breaks off when trying to remove it... Again, not a huge deal..

 

The transmissions on these are excellent... Just make sure you keep the fluid changed regularly, and you should be fine (provided you don't do tons of burnouts :lol:)... I ran the one in my old Lumina LTZ to close to 150,000, and it had absolutely no issues when I got rid of it, but I also didn't experience the other 2 issues either...

 

That's pretty much the common issues the 3800 has... Neither one is really a big deal, whether you do it yourself or take it somewhere to be done... Hope this helps you out some..

Edited by 88red4cyl
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Actually the 3800 has LIM failures just as much as the 3x00.

 

IMHO, the 3800 is much easier to work on. LIM gaskets take roughly half the time as the 3x00.

 

True dat yo.

 

AS for LIM gaskets though, they do fail on the Series 2 3800's, but don't confuse the problems with the Series 1 3800's. Those will go 200k on original LIM gaskets without a problem.

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IMHO, the 3800 is much easier to work on. LIM gaskets take roughly half the time as the 3x00.

 

Yes it is..

 

I was just posting from my experience on the LIMs.. I had my 3800 car for 4 years, and my sister has had it for 1.5 now, and the original LIMs have never been an issue as far as leaking (but neither has the UIM, and the car has around 170k on it now)... I got my 3100 car that had less mileage, and the LIMs became an issue within months of me purchasing it...

 

I'm not disagreeing it's a problem (I would change it regardless when doing the upper intake since the 3800 is so easy to work on), I just think it's not nearly as common as the 60° failure rates.. Again though, this has just been my experiences...

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I have a 98 LTZ with 200k on it and the only issue im having well, had because i took it off the road, but i still might fix the car, is the manifold warping problem. and that didn't start untill about 2 oil changes ago, the leak is small and didn't really seem to matter, unfortunately i had already bought the reinforced upper just before i wrecked it. the transmission is flawless, I changed the fluid and filter once at about 150k. My vehicle has been very well maintained since 50k though and that weighs very heavily on the performance and reliability of well any vehicle.

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3800's are great motors even after the whole LIM gasket/coolant elbow issues. If you decide to get one....and replac the LIM gaskets make sure to get the GM aluminum gaskets. They will last forever. It's really hit or miss on how quickly the original gaskets go. I've seen 3800's blow the LIM gaskets at 80K.....and have seen ones w/ 150K+ on the original ones. The ones I pulled off my GTP when it was at 102K were absolutey perfict. I only changed them when I wet to swap to a Gen V blower/LIM.

 

Also, on top of doing the aluminum GM LIM gaskets, if you're looking at an L36 (NA) replace the UIM with a Dorman upper intake. You can get them at ZZperformance.com. If you're going with the L67 (supercharged)....again Aluminum LIM gaskets, and go with a STOCK GM replacement supercharger gasket if yu were to ever replace them. Do not do a Garlock gasket on the blower.....I had alot of vacuum problems with a Garlock S/C gasket on my old Gen V setup. Supecharged 3800s typically do not have problems with the original S/C gasket though....just the LIM ones like the NA 3800s.

 

A little bit of maintenence goes a LONG way on these motors (both N/A and S/c) They are fun, quick, and are very easy to make more power out of with a few mods.

Edited by 9lumina6
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one good thing about the 3800's is the factory head gaskets on them are virtualy indestructable.

 

Thats good to know one less thing to worry about lol.

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I really have nothing negative to say about my Impala (other than horse shit electrical/security issues im always dealing with). I literally just came in the house from working on the 3.8. 161,000 miles. Just replaced the LIM gaskets with gaskets from GM. Also replaced valve cover gaskets, elbows, cleaned TB, and spark plugs. I did this about 70k ago and they started leaking. But come to find out the half my bolts were loose on both the upper and lower intake. So this time around i put some blue lock tight on everything and torqued it down. I too replaced the Upper manifold with one that has a steel sleeve where the egr goes.

 

Also, if the conditions are good, you can still achieve great mileage. I drove from Milwaukee to Toledo on a sunday afternoon and i got 33.3 mpg. And that is actual math.

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