heads-up warning: this will probably be a lengthy post so, well, I'm begging your indulgence ahead of time. Please and thank you!

2006 Pontiac Torrent AWD 150k miles. Purchased from friend'* mechanic in August w/'new' (donor) engine. Long story shortened, I believe shop made rookie mistake on install which snowballed into blown head gasket. Details later (if necessary) but upshot is: drove with bhg for months, mostly w/o issues (yes I know, at time there was really no other choice!). (BHG diag confirmed w/ exhaust gas detection test). Recently threw p0300 and 0301, changed plugs & wires: FAIL. ONLY reason I even tried fixing that issue before tear-down is I want/need to remove cooling sys oil contam before rebuilding half the engine.....and it really needs to be operational for best outcome
SO: Here'* what I'm after: some valid, experience based advise on parts sourcing. With one exception, I haven't worked on any domestic autos in decades and I have no idea what/who makes best parts, gaskets etc for this car. W/my Tacoma I KNOW what/who to use or not use.....Toyota OEM, spendier but mostly superior .....When I put new cylinder head on Tacoma couple years ago I knew exactly what I was getting into, how to do it (and where to seek help if I ran into trouble) and where/what to buy parts-wise to avoid future problems.
What I know about this Torrent is: !1 (probably should have run the other way instead of paying for an unsupported product from a defunct and problem-plagued manufacturer...but I digress, sorry!) The 'OEM' supplier, AC Delco, no longer manufactures their parts and sources from any/everywhere so product 'quality' is a crapshoot. As I understand it, the infamous, failure-prone intake manifold gaskets continue to be sold by GM and one should purchase the re-engineered, upgraded components on the aftermarket. Let'* just say I've no faith in OEM here. Head gasket set: who and what kind? I do NOT want to work on this car (plugs and wires were nightmare enough!) re-work due to cheap crappy parts is not acceptable. Do I go Cometic? Mahle? Fel-Pro? What type? MLS? I don't even know what GM used at build, I do know they were not very robust and seem failure-prone. What other issues typically arise when doing a head gasket on these engines? Are there other components I should check and or replace while disassembled? I will be putting a 'serpentine kit' (think that'*' what it'* called: belt, tensioner, idler pulleys). Has new 'fail-safe' thermostat, new water pump already). Suggestions on sourcing the serpentine kit? I don't mind spending more for quality but money IS an issue, I'm unlikely to be working for a while (and will need dependable, operational vehicle when I do get dispatched).

I'd really like to hear from those of you with an informed opinion and or relevant experience(*). I'm certain I can't be the first person to need this kind of help and prob won't be the last so please chime in. Thank you for taking the time to read this min-epic, thanks in advance for your input.

Details please. Since you are looking for assistance and opinions, it would be helpful to know the details of the mistake that may have caused this issue.

What were the symptoms of a blown head gasket while you were continuing to drive with a blown head gasket?

So this is the LNJ 3.4 V-6. an okay engine for many years in many makes and models of GM. Yours was probably built in China by SAIC. In 2006 . I think they are better at stuff now.

I've never had a problem with Felpro. They often have improved versions of gaskets as well.

A lot of this answer depends on the symptoms. Warped head(*). burned rings, thrashed bearings top and bottom, etc. etc. Depends.

Replace the water pump while you're in there. Does it need belts, wires, plugs, alternator, etc.? Depends on what you need to pull off of it as you get into it.

I've never heard of a 'serpentine kit' as you describe it. Maybe it'* a thing that I never look for. I just get a good brand, usually Gates or Dayco, of the parts I need. I do belts on the factory schedule, or sooner if there'* some damage. Pulleys can last a long time. Or not. I replace those when they have issues, or sometimes I replace all idler/tensioner pulleys when one goes out.

thanks for the reply CathedralClub.
In re: the rookie mistake: surge tank was old (opaqued to the point that contents not visible without looking through fill opening) and brittle. The hose nipple at the bottom of the tank developed a crack above the hose attachment -the crack (of course) leaked- but only when system under high pressure, as on long trips- and made determining the cause of disappearing coolant (and, eventually, overheating) very difficult. After flushing the cooling system (backwards and forward, refilled with new +distilled water), replacing the thermostat (with a 'fail-open' upgrade) water pump and several hoses, I replaced the surge tank along with the remaining hoses. Too late, the damage was done. The root cause, that cracked hose nipple ,it remained in the hose -see pic

(encountering technical difficulties) (going to have to make separate post for correct pic, sorry!)

ok, gonna try this again

Ah, okay that makes sense. Pressurized reservoirs are bad that way when they have issues.

Moved thread from "General GM Chat" to "Pontiac".