Some have said they'll go 300,000+. Never seen one in person but its believable with how strong these motors are.

Actually the Supercharged 3800 motors aren't any worse on gas than a non supercharged 3800 (within a couple MPG'*) and reliability doesn't change much either with regular maintenance.

Yes and it is said that the 3800 is the best motor GM has ever made. They run a long time

I have never seen one in person reach 300k either, but i sold my last car with a similar motor when it had almost 170,000 miles on it, and it still ran unbelievably great. There are a lot of factors that go along with how long a car will last, but just make sure you change the oil and trans fluid when u get it, and keep up with everything. Drive it nice and it should last quite a while yet.

Well, I just hope that I will soon be able to love a Bonneville as much as you all have. So, these things are generally cheap to maintain, good on gas, generally cheap to insure, while being fun to drive?

My SSEi was horrible on gas. I was lucky to get abouut 12-15 city and 18 -20 hgwy. I found a Bonneville on IAAI that has 351K. Looked pretty decent until the accident..... Pic attached

I have seen well over 220,000 miles on a 3.8L engine. My daily driver has 178,000 and I would take it anywhere. Like anything else, you have to maintain it and try not to beat the thing to death if you want it to haul you around for awhile. That all depends on how you drive I guess. If you want to be sure before you buy it, ask if you can have your mechanic check it out. Hey, a few bucks up front for a good looksy could save you a ton in ca$h and aggravation later! Good luck....

Talk to some Northstar mechanics. They'll tell you that you HAVE to beat on it from time to time for it to be reliable. The problematic northstars are those driven by old people who never really step on the gas. Keep reading to see why.

Mine has 216k miles. I replaced the heads recently because I burned a valve pulling a very heavy load up a Colorado mountain at 4800 RPM for 5 minutes straight. That will do it I suppose.

Aside from that, I checked my compression and the bottom end is rock solid. All cylinders reported in between 186 and 190 psi, with 3 of them being dead on at 190 PSI. I've had the car since it had 61k miles on it and I have beat the living **** out of it every single day. It seems if I don't beat on it, fuel economy goes down! Strange, I know, but I average 20.5-21MPG every tank of gas, while beating on it. Highway only fuel economy was recoreded with the bad heads from Chicago to northern wisconsin and back at 30.6 MPG average at 70mph average, and that'* not some computer reading, that'* the calculation of gallons pumped to miles driven.

The concept is that you need to take an occasional trip to redline to heat the motor a bit, break some carbon loose, and keep carbon from building up. Carbon kills engines. It gunks up your valves, prevents them from sealing, makes it easier for them to burn, it kills your piston rings, and etc. Run a can of seafoam through the intake every 10k miles, and do an italian tuneup every now and then. The jaguar XJS guys swear on it because the cars generally run pig rich and are more prone to this type of thing. Here'* what they have to say:

And from wikipedia:
The reason you don't see very many 300k+ mile 3800'* around is for two reasons. Either 1. the transmission goes at somewhere in the 200'* and people don't want to spend more money rebuilding it than the car is worth, or 2. the body rusts away before the engine ever really starts to wear, both of which merit a visit to the scrapper in some peoples' eyes.

Beat on the engine all you want. You cannot kill a properly maintained series 1 3800, even if you overheat it a slight bit 3-4 times (needle right before the red line) as I did. Just don't overheat it severely or your bottom end will kick the bucket. Take it from me, I've tried to kill it, and it won't die. 216k miles now, and counting, and WOT runs to redline every single day.

My 95 SSEI is at 249,177 as of today. Still runs great and I drive it semi hard everyday. I replaced the lower intake manifold gasket on it last spring. The 94 Park Avenue still purrs like a kitten. About 184,000 on it. Will replace the LIM gasket on it on Monday. My wife drives it everyday.

i gave my 1993 SE Custom to my dad with 240,000 and it still ran and shifted perfect. ive had non series 3800 motors with close to 300,000 miles but then i wreck em before they get there.

Sounds like you should have your answer here buddy. So long as you don't overheat the hell out of this car, you should have no problems picking one up with 180k miles on it.