Buick 3800 Series-2 Intake Manifold Questions

[ls1mike]

It's surprises me that it's difficult to replace an oil pan gasket. Mine is either not leaking, or only a minor drip at most. I'll just check bolts tightness. How tight is proper?

Yeah well it surprised me too...lol. Just feel it. Not a great answer but if you have been doing it awhile you will know. I got a 1/4 of a turn on the 2001 GTP I had, never leaked again.

 

[Carlostrece]

Yeah well it surprised me too...lol. Just feel it. Not a great answer but if you have been doing it awhile you will know. I got a 1/4 of a turn on the 2001 GTP I had, never leaked again.

I'm a near encyclopedia of Jeep Cherokee XJ and Wrangler TJ/LJ knowledge, including Jeep 4L engines because I participated in maintenance and upgrades on them for 23 years.

I've owned my Buick Park Ave for 15 years, but only done fluid changes and 1 tuneup on it plus a couple minor repairs. I never tried to get intimately familiar with my Buick until lately. So I don't know as much about Buicks. I do know that I've come love Buicks and Oldsmobiles, especially the full size ones with 3800s. Park Ave and Olds 98 are fantastic full size luxury cars and the ones with 3800s get good gas mileage too. I love them, but I'm still learning how to take care of them.

 

[ls1mike]

I'm a near encyclopedia of Jeep Cherokee XJ and Wrangler TJ/LJ knowledge, including Jeep 4L engines because I participated in maintenance and upgrades on them for 23 years.

I've owned my Buick Park Ave for 15 years, but only done fluid changes and 1 tuneup on it plus a couple minor repairs. I never tried to get intimately familiar with my Buick until lately. So I don't know as much about Buicks. I do know that I've come love Buicks and Oldsmobiles, especially the full size ones with 3800s. Park Ave and Olds 98 are fantastic full size luxury cars and the ones with 3800s get good gas mileage too. I love them, but I'm still learning how to take care of them.

If you have been doing the jeep stuff you will know right away how tight you think those oil pan fasteners can go. Good thing about those 3800/4T65Es is they are pretty easy to make repairs on.

 

[Carlostrece]

If you have been doing the jeep stuff you will know right away how tight you think those oil pan fasteners can go. Good thing about those 3800/4T65Es is they are pretty easy to make repairs on.

I never did anything with a Jeep oil pan. It wasn't necessary. The bottom end on Jeep 4L is very reliable. So no I don't have experience knowing how tight oil pan bolts should be, but I can guess, or follow advice you gave, or find my Hayes or Chilton maintenance/repair manuals that I've misplaced.

 

[carviewsonic]

I never did anything with a Jeep oil pan. It wasn't necessary. The bottom end on Jeep 4L is very reliable. So no I don't have experience knowing how tight oil pan bolts should be, but I can guess, or follow advice you gave, or find my Hayes or Chilton maintenance/repair manuals that I've misplaced.

From GM forum.com
Oil Pan Bolt 14 Nm (125 inch lbs.)

GM used a sealant (no gasket) on my ‘04 Park Ave. oil pan. Had to have it resealed at only 40k km’s. I’ve had three other 3800’s in the past, which never had an oil pan leak.

 

[tbm3fan]

The 3800 gen 2 should have the upper plenum changed with one that uses a metal sleeve and reduced diameter egr chimney. The OE has a habit of burning through the plenum. ATP has a decent one with all the necessary pieces.
The other common point of failure on these is the plastic coolant elbows, change them for the aluminum ones from ZZP they have decent o rings on them, the Dorman o rings are not good but the elbows are good, use OE or rings with these.

Look for corrosion in the holes the elbows go into, if corroded clean it well and use a smear of RTV in there before installing. Don't forget to install a new PCV in the new plenum and a new OE thermostat (OE only from the dealer). Flush the cooling system with the lower hose removed and the hoses going to the elbows and refill with JD Coolguard 2 from any John Deere dealer, it will not harm gaskets and seals and is perfect for mixed metal engines and change the oil and filter. Just my own experience after doing many of these over the years.

https://atpautomotive.com/engine-intake-manifold

https://zzperformance.com/products/...zzkUOIIqZtj_8oX8-JxU4QocnfN1aYb3CdRNhGDBUkbrw

Just be aware that the replacement egr chimney maybe the wrong size if they haven't updated their upper intake parts. I did the job two years back and found that the enclosed fitting's base diameter was 0.75" while the lower intake took a 0.675" (I believe) diameter. I had to put the original upper intake back on while I had to take the fitting down and lathe it to the correct diameter. I got two of them in the same large size.

 

[Carlostrece]

Just be aware that the replacement egr chimney maybe the wrong size if they haven't updated their upper intake parts. I did the job two years back and found that the enclosed fitting's base diameter was 0.75" while the lower intake took a 0.675" (I believe) diameter. I had to put the original upper intake back on while I had to take the fitting down and lathe it to the correct diameter. I got two of them in the same large size.

Did you use/have that problem with an aftermarket ATP plenum/upper intake manifold or some other brand? What year is your Buick 3800 Gen 2?

 

[Carlostrece]

I want to buy an OE thermostat from dealership, but there's no Buick dealership in my town anymore. Suggestions? RockAuto perhaps?

 

[Lawnman23]

I want to buy an OE thermostat from dealership, but there's no Buick dealership in my town anymore. Suggestions? RockAuto perhaps?

https://www.rockauto.com/en/moreinf...PyjHEaccL6FfvAuQymRxTnxOCJ80D+/x3tvcImJl13Ps=

 

[tbm3fan]

Did you use/have that problem with an aftermarket ATP plenum/upper intake manifold or some other brand? What year is your Buick 3800 Gen 2?

2004 and the intake was bought from Graywerks (?) back in 2018. Looking on Amazon the picture for the ATP Graywerk's intake seems to show two stove pipes but of two different base diameters now. Except one picture shows two different base diameters while another picture shows them to be the same size. ??? I understand that earlier models used the 0.75" diameter base while late models used the smaller diameter.