3.8 vs 3.1??

Hey everyone,

I'm looking to buy my first car for college next year, and my budget is very limited (bout 5k, give or take a bit). I like the Lumina, and I've heard the '98 is an especially good model year. I've heard some things about the 3.8L engine being way more reliable and better built than the 3.1L. Is this true? I know that the performance is way better on the 3.8, but my priority with this car is reliability, and the car's I'm looking at all have about 60-70k miles on them. Plus, if I get a 3.1, then the rest of the car will be in way better shape compared to a comparably priced LTZ. Will a 3.1L break down on me as soon as I buy it? Thanks a lot guys.

Both are very good motors. 3.1 will get better fuel mileage and still have plenty of power. I've had both.. It won't break down. I say for your circumstances 3.1 all the way.


Hey everyone,

I'm looking to buy my first car for college next year, and my budget is very limited (bout 5k, give or take a bit). I like the Lumina, and I've heard the '98 is an especially good model year. I've heard some things about the 3.8L engine being way more reliable and better built than the 3.1L. Is this true? I know that the performance is way better on the 3.8, but my priority with this car is reliability, and the car's I'm looking at all have about 60-70k miles on them. Plus, if I get a 3.1, then the rest of the car will be in way better shape compared to a comparably priced LTZ. Will a 3.1L break down on me as soon as I buy it? Thanks a lot guys.

I have two 3.1 I like them alot (or I wouldnt have two) lol. If you really want to know thow read threw the problems people are having so you can get an Idea what each cars certain types of problems are. As you read you can see that they are all pretty much relaited in one way or anouther. all are fairly easy fixes...

I have a 1999 3.1 and I have a had a few minor things go wrong but other than that it is a very reliable, comfortable car. The reviews on the 3.1 are good too!

With gas being the way it is, I'd suggest the 3100. It gets good mileage and puts out plenty of power for your needs (assuming its just a "point a to point b" ride and not the next indy 500 car)

I have had 2/ 3.1 v6's they both were garbage the first one was in a firebird that steadily detuned itself even though myself and other mechanics tried to stop it from doing so.The other is in a lumina van I currently own. It is weak but I will give it high reliabilty points,it always starts but runs poorly until you position the throttle just right despite the sensor changes and other advice from these fine gentlemen from this forum....test drive ,it look it over really good ,and if it thrills you,buy it . P.S. there is not that big of a difference in fuel economy,check gm spec sheets.

I have a 90 3.1 with 107,600 miles and that motor rules as far as I'm concerned.

to each his own I just haven't had any luck with them

They are both good engines. The 3.8 has a little more power, but they both get good gas mileage and really reliable. Just keep the PM's up on them and they will run along time. I own them both at this time.

If you are looking in say the 97+ model years, the 3.8 has at least 10 more hp, but a lot more torque - at a lot lower rpms, plus it will run forever.

since 94 the 3.1 has been 'gen 3' and they finally fixed the #3/4 rod oiling problems which claims pretty much *all* of them by 200K, and the head gaskets are pretty solid, but the intakes fail just as bad as the gen 2 (and the part is more expensive) and now they are full of acid (deathcool) to wipe out the bearings when they mix - even just a few drops - and for grins, the intakes on the gen 3's CANT be fixed properly, whereas the gen 2 could be fixed forever with the proper felpro intake. thats something to consider with book labor being 8hrs+

if you are stuck on the W body - for the same $$ look into the regal - buicks tend to be owned by older buyers and hence dont get thrashed daily and the regals almost exclusively come with the 3.8 rather than the 3.1.

I rebuild a lot of 3.1s which then go 300K easy, the 3.8s will do the same with no rebuld, but those cars tend to be pricier.

of note, take a look at larger C bodies (lesabre, park ave, 88, 98, bonnie) say 96-97ish for the same money. You will get a car that is loaded to the hilt, will get a good 26mpg hwy and have a bulletproof 3800/4t60E combo and likely never been over 60mph in its lifetime.

i have a98' lumina sedan and i think its tha bomb it has a 3100 and with gas so dam high its realy reliable i get about 235 - 250 milage wise im gonna put a 3800 in it if i dont have to put a new tranny in it.

will the 3.8 work in the motor mounts of a 3100 ?

My '97 3.1 has been a great car. The 3.1 is a robust little motor, I drive the crap outta it. I have 115,000 miles on it, bought it new, and have put in 1 battery, 1 water pump (it didn't need it, but we were going on vacation, and with 65,000 miles, it was due to fail) 1 serp belt and brakes. That's it. Love this car!!

Most of the 3.8's ive seen have had lots of problems right around 100,000 miles. Mostly just bad sensors, but it usually ends up being about $700 - $900 to fix it all. Really though, any used car you buy is gonna have problems. Just be sure to look down into the crankcase through the oil cap before you buy it. If its a light brown/bronzish color, its probably been fairly well taken care of. If its got tar and chunks of crusty black stuff, move on to the next one.