'99 Park Avenue - 3800 - Intake manifold failed.

[mrsilv04]

It finally happened. 1999 Park Avenue, 87,000 miles.

Took it in for the rear brake pads, and while the mechanic was driving it to check the brakes, the coolant passage through the intake manifold failed. He barely got it back to the shop before the plugs finally fouled out from the coolant that got sucked into the engine.

So, here's the dilemma. Since the intake manifold has to come off, should we also do the lower manifold gaskets while we're at it?

The cost to replace the intake manifold and gaskets (plus a set of new plugs... which it was close enough to needing anyway) is $345.

To keep the costs down as much as possible, the shop is going to use a good used intake manifold that is stamped as manufactured in late 2004. It came off of a car that they sent to the junkyard after an accident. They're going to throw in the used manifold for free.

For another $190, they can do the lower manifold gaskets as well. They'll be using the special Fel-Pro gaskets on everything.

For the additional $190, I think it is a "no brainer". However, the shop seems to think that I'm being over cautious in wanting to replace the lower intake gaskets, as they tell me that they just haven't seen that many failures.

 

[The_Eric]

YES!!!! For sure, do both sets and replace the upper and stove pipe!

 

[Jim 5]

I think it's a no-brainer too. I would go for it. That should take away the major failure points of this engine and it should be good for a long life after that.

Otherwise, you'll just be waiting for the other shoe to drop and you risk having the added expense and hassle of going through this all over again.

Good choice in the Fel-pro gaskets. Make good and sure they use the really high end ones. When I did the LIM gasket in my '98 K1500 5.7L v8, they were called Fel-Pro "Problems Solvers".

 

[Scienceman]

Those things are failing everyday here!

 

[Drew99GT]

YES! But make sure they use the very latest updated GM metal frame gaskets. Those are better then the Fel pros for this application (the GM 3800). Also, a manifold off a 2004 will fail again. You need one of the newest aftermarket pieces with the reinforced EGR stovepipe. DO IT RIGHT, or it'll fail again. The factory replacement manifold we got installed on my pops Olds 88 failed again, and I decided to just dump in a can of Bars Leaks and it sealed it.

 

[warrior]

The gaskets or the 3800 engine? Don't mean to be rude...but I would get the thing running and get a Honda. I had a 3800 that ate the timing gear. Problem was that GM knew it would fail and did not care. I will just have to be a dart board on this one.

 

[Drew99GT]

http://www.bobistheoilguy.com/forums/ubb...rue#Post1350640

Member lght1 is the authority on the GM 3800 problems.

 

[Drew99GT]

http://www.ineedparts.com/auto-parts/intake-manifolds/gm-intake-manifold-kit-17806.html

 

[Jim 5]

Originally Posted By: Drew99GT
http://www.ineedparts.com/auto-parts/intake-manifolds/gm-intake-manifold-kit-17806.html


Nice find!

Hard to imagine that an intake manifold itself is a consumable, but obviously it is. I would go with that one given the majority of the cost is labor, which you don't want to waste installing inherently flawed parts.

 

[Stu_Rock]

warrior, that's kind of a trollish thing to say.

 

[UNC017]

Originally Posted By: Stu_Rock
warrior, that's kind of a trollish thing to say.


Nah, he just prefers changing transmissions to changing intake manifolds

 

[RnR]

Originally Posted By: Drew99GT
http://www.ineedparts.com/auto-parts/intake-manifolds/gm-intake-manifold-kit-17806.html

Is this the "Smartest Buy" those of us looking at this repair could make? They don't specify if they are GM gaskets or not (in the LIM gasket kit) but the two packages together look pretty complete save the (2) coolant elbows AFAIK.

 

[J_Sap]

I bought a used 95 Bonneville with a 3800 engine in 07 that the owner had just replaced the upper intake manifold on and did NOT touch the lower one. After I put 15K on the car the lower failed and the upper intake actually warped at the plastic stovepipe area (wish I took pictures). I replaced them both for so my brother this summer so he could use the car.

I would HIGHLY recommend replacing both the lower and upper gaskets and getting a new intake with the metal stovepipe. If you cheap out you might be replacing everything again. So what if you save $100-200 dollars today, you'll be spending $6-800 tomorrow.

Also you could always buy the intake from advanceautoparts.com with coupon code BIG40 to get it for $90 shipped.

 

[mechanicx]

Here is some pretty good info on it.

Read about the problem here: 3800 series II intake manifold problems

And how to fix it here: Replace UIM/LIM gaskets

 

[severach]

Pontiac Bonneville Club: 3800 Series II Vin K Upper Intake Information

The APN UIM with the steel ring is the only one you want. The air gap between the ring and the reduced chimney give this part an unlimited life. All the rest maintain the same design flaw where the hot EGR chimney touches the plastic and will die again. Each failure risks engine destruction.

The metal frame LIM gaskets from the GM dealer are the best. If you ask for 1999 you'll get the cheapie plastic. Let them rot on the shelf. Keep upping the year until you get the good ones. 2004 ought to do it. The side gaskets won't be right but you don't need them.

Always replace the coolant elbow.

The UIM and LIM gaskets is the major flaw with this engine. Once fixed right it will run as long as any Honda.

 

[sciphi]

Mechanix, those links are superb resources. One of the guys who wrote the first link helped wrench on my Buick replacing the lower gaskets. They most definitely knows what they're talking about, as they have done those on dozens of different 3800 V6's. It's been 25k miles and 1 year since mine were done, and there have been no problems (knock on wood).

The APN upper intake manifold and GM aluminum lower intake manifold gaskets are the best you can get right now.

It's a no-brainer to have the lower gaskets done at the same time since they'll likely fail shortly after it's all together.

 

[Drew99GT]

Originally Posted By: RnR
Originally Posted By: Drew99GT
http://www.ineedparts.com/auto-parts/intake-manifolds/gm-intake-manifold-kit-17806.html

Is this the "Smartest Buy" those of us looking at this repair could make? They don't specify if they are GM gaskets or not (in the LIM gasket kit) but the two packages together look pretty complete save the (2) coolant elbows AFAIK.


Yes, but use the GM intake gaskets. You'll have to buy them separately.

 

[mechanicx]

Wow you know the guy who wrote that info post? It's a small world. I agree, it probably is the best write up on the topic on the 'net or at least that I know of. The link has the part numbers for the APN parts and the GM aluminum gasket and elbows, etc. They should be the correct ones for all the listed series II years.

 

[sciphi]

Yeah, pretty small in some circles.

If the OP can get the whole job done for around $600 including parts in a garage, it's a reasonable price. $200 is parts/supplies alone.

Those are the right parts for every year of the Series II 3800.

 

[mrsilv04]

Originally Posted By: Stu_Rock
warrior, that's kind of a trollish thing to say.


There's always one out there... Thankfully, they're usually easy to ignore.

I've had Hondas before, have two right now. They have their own issues and are far from perfect as well.

I knew that when I bought the car, that there would be an unavoidable $600 repair sometime in the future. Since the car had 44,000 miles on it when it was purchased, I strongly suspected that nothing had been done to it, to deal with the problem.