Join Date: Jun 2018
Location: Denver, Colorado
Not only have been fixing cars since the early 90's but also worked for a radiator shop I have seen this and know why first hand. The Intake gaskets leak. This is because #1 Dex-cool has been proven in a court case to eat gaskets after about 50,000 miles. It gets acidic and eats away at those specifically as they get hot, are thick plastic and a poor design. #2 Dex-cool also breaks down to turn into a "sandy" type of sludge which blocks the radiator, heater core, lines ect. You have to not only replace the gaskets but blow out the entire cooling system with water and compressed air. I recommend replacing the coolant with good old green ethyl glycol anti-freeze. It has been around for 100 years with no issues and anyone who says it will harm your car is full of you know what and has little experience working on cooling systems day in and out. Automotive manufactures made this proprietary coolant to make you have to buy from them or a company to buy patent rights or lease them to produce this coolant. It is a scam in the worst way. They (GM) have known this for years and it effects ALL GM front wheel drive cars with Buick V6. Yes your Pontiac has a Chevy engine redesigned off the good old Buick V6. This is the GM 3.1L, the 3.3L, the 3.5L, some 3.8L, two different designs, and the 3.9l. This problem also plagues GM trucks with the Vortec 4.3L. The other Buick 3.8L had the worst design of having 2 plastic heater tubes that actually go thru the alternator bracket hidden underneath it which would break and dump ALL of the coolant out almost immediately. To this day the only place I found to buy the metal replacement for those GM cars was Autozone. I am not endorsing them buy the way. And it is a bit off topic as that is not a G6 engine. But a little facts on the coolant problem GM knew about and lost a pretty big law suit over and STILL puts DEX-cool in cars to this day?...... Why......Money....Oh and by the way, they do sell a aftermarket kit with aluminum gaskets with rubber embedded to prevent this. There are also no gaskets on the flat plane between the two heads on either side. You use about a 1/4 inch of black RTV silicone. Slightly over lapping on the gasket. The gaskets them selves get no silicone. NONE. This requires the removal of the rocker arms and I found the easiest way to keep them in place for placement back in the right cylinder is to get a box and just stab them thru and label intake, exhaust cyl#. Let that RTV set up for about 10 minutes to "tack up" also. Hope this helps. PS this is the lower intake gasket set, the upper is the plenum, and you need to get both when doing the lower job. This is also a good time to do a tune up as your already right there. A oil change is mandatory with the filter as well.
Last edited by jayram1408; 11-04-2018 at 05:06 PM.