GM 3900 engine.

[JTK]

Is there anything horrible about this "High-value 3900" 3.9L series engine? I'm not scared of these "old" pushrod GM V6s LOL.

Reason I ask is, in the not so distant future one of my kids will be driving and we'll eventyally have the need for another car. I've been eyeing a 2011 Buick Lucerne for this purpose that has this engine.

 

[Dorian]

From what I understand, the lower intake manifold issues were not nearly as bad as they used to be. If the car was maintained properly and the dexkill was removed at and appropriate time, the car should be ok. I never liked the term "high-value". It just sounds like a poor name to compensate for an otherwise outdated design.

 

[SteveSRT8]

Most everyone has realized that dexcool was not the issue. The gasket material was poor. It is recommended to simply replace the gasket with an updated one and end the problem for good...

 

[jeepman3071]

I hate to be the typical person who just repeats "buy a Toyota" but for first time drivers I'd buy them a cheap (but decent) Honda or Toyota. You want something safe and reliable, but the statistics are they will likely crash their first car.

 

[14Accent]

The 3900 is an excellent engine, however if you want simplicity I would go for an Impala or the like with the 3.5 instead.

The 3900 has AFM as well as VVT, which adds another layer to things that can go wrong. The 3500 has VVT only, and they're mostly bullet proof. Intake gaskets are no longer an issue, the coolant now flows through the coolant crossover which is on the passenger side of the cylinder heads. Those gaskets DO leak, however it's much less involved to change them, somewhere around 2.5 hours vs. 6 for a LIM job on a 3100/3400.

One bright side of buying a Lucerne: with the 3900 installed the engine bay is HUUUUGE. The Lucerne is based on the Cadillac DTS platform, therefore was designed (and equipped with) the Northstar/4T80 combo. When you put a 3900/4T65 in it's place it almost looks like you could slide an entire 4 cylinder in next to it.

 

[RamFan]

No mechanical issues with the 3.9l in the Monte. However, I've leaked oil out of every gasket. Last gasket to be replaced is the Oil Pan and since I have to drop the cradle to do that job, I'm just letting it be.

 

[Drew99GT]

Yup, hate to say it, but the 3500 and 3900 High Value engines are pretty much junk after 100,000 miles IMO; our Impala with the 3500 has also had the oil pan gasket replaced, head gaskets replaced, water crossover gaskets replaced twice (this was the design GM implemented to curtail the previous intake gasket fiasco - FAIL (it uses a cheap o-ring style gasket that has been redesigned multiple times but still leaks). Stop leak has worked to stop the coolant leaks for now - it gets expensive coughing up 500 bucks every 50,000 miles for gaskets!

Engine still runs great though, it just leaks like a sieve from every gasket - including multiple transmission leaks.

I wouldn't touch one with a 10 foot pole personally; would never buy a GM EVER, even if someone put a gun to my head, but if you like the car, know it has potential issues.

 

[BrocLuno]

So, for a first time driver - why the Lucerne ... Kind of a big box to fit into places newbies try to fit vehicles

 

[JTK]

^ Just thinking ahead. I've seen a few last year production of these Buicks for sale locally pretty cheap. Kids will most likely use my Forester and I get the ol'man cruiser for my work commuter. Insurance will be a killer for me, thus a vehicle that has as low insurance cost as possible.

 

[JustN89]

Originally Posted By: 14Accent
The 3900 has AFM as well as VVT, which adds another layer to things that can go wrong. The 3500 has VVT only, and they're mostly bullet proof. Intake gaskets are no longer an issue, the coolant now flows through the coolant crossover which is on the passenger side of the cylinder heads. Those gaskets DO leak, however it's much less involved to change them, somewhere around 2.5 hours vs. 6 for a LIM job on a 3100/3400.


I've read on here and other sites that the LIM gasket issue was pretty much resolved by 2003/2004 for the 3100 and 3400 series motors. How does the problem perpetuate on a different engine that came into existence in 2004, when the problem was supposed to be fixed? If the LIM gasket was really an issue with the 3500, I don't see how it wouldn't still be an issue for the 3100/3400 series motors.

As for buying the Lucerne, just be wary of the 4T65E. Drop the pan and make sure it has had new magnets installed per TSB 08-07-30-040C. It should, being a 2011 and all, but I would still check. I also added a few extra in my 4T65E, just to be safe. While you're at it, replace the filter and use Valvoline Maxlife ATF. I have found it to work really well.

 

[Silverado12]

I'm a GM fan but stay from those engines; they have gasket problems (incl. headgasket) like others said.

 

[clinebarger]

Originally Posted By: Silverado12
I'm a GM fan but stay from those engines; they have gasket problems (incl. headgasket) like others said.


I'm a GM guy as well, And I agree....Stay away from the 3900. Not a huge fan of GM 60 degree V6 engines in any form really.

If you want a Buick Lucerne.....Get a Northstar/4T80E.

 

[Linctex]

Originally Posted By: jeepman3071
You want something safe and reliable, but the statistics are they will likely crash their first car.


I didn't crash my first car, or my 2nd.... it was the 7th (just a minor fender bender)

I was 20.... 7th car at 20 (but still had 3 previous ones)

 

[PeterPolyol]

Boy, I'm sure glad our first and only GM 60 degree V6 is the last year of the non-VVT models. Everything that should have been revised was revised, then they made it for 2 years and nixed the whole series for this new one. Our old 3500 has a relatively short 200K KM/160K Mi, no Dexkill, no oil burning and all original gaskets. No leaks. Lucky?

 

[PeterPolyol]

oops 200,000KMs is 120,000Mi, thinking too much of the 1.6x factor conversion rate

 

[HM12460]

I would be more concerned about the transmission than the 3900 engine in this year Buick. Although the 3900 isn't all that great either. Might be much better off looking for a 2012/13 Impala withe 3.6