2004 Buick Rendezvous 4.3 V6

Our Buick started to over heat and lost power. Mechanic told us the head gaskets were hooped. Looking on line, some say the intake upper and or lower gaskets are hooped. I do have a small oil leak from up behind the engine some where. Fire wall side. I am looking at taking the heads off and maybe the intake? Never attempted this before. Looking for help in how to disassemble.
Thanks in advance
Gharvey

4.3? Thought they only came in 3.4 or 3.6. I found a shop manual online couple years ago but no clue where I downloaded it from.

My bad, I went out and looked, maybe dyslexia, it is a 3.4, thanks for bringing to my attention.

You want to verify first, whether it's the lower intake gaskets,

OR,

the head gaskets......if you just do the lower intakes, and it is a head gasket, you end up doing the intake job all over again, just to get to the head gasket(s)......

If a head gasket, more often than not it is #1 cyl...rear bank, passenger side....

Pressurize the coolant system overnight on a warm engine.....next day, remove plugs, disable spark and fuel.....have someone crank mover the engine....if head gasket, can almost guarantee coolant will come shooting out of #1 cylinder hole....

I have already drained the oil and antifreeze from the vehicle. Found no oil in the antifreeze. And no antifreeze in the oil. Good sign. Did have small oil leak behind engine some where? Firewall side. Thanks for tip. Going to pull down to and including heads. Overwhelmed what to start pulling first on engine? Getting rad out of the way first.

Removing the radiator does not help make the job any easier.....