For anyone with a 3100 and has a coolant loss problem

[doobiess]

Well today after alot of researching I found something out. Well on my 94 GA 3100 v6 with 265000kms on it has a overheating problem and couldnt quite figure out why and had coolant dissapearing and not knowing where it was going. My dad told me to do a leak down test I think it was called by putting about 25-30psi in a cyl.. by removing a spark plug and seeing if any air would come into the cooling system. Well I went through all cyl. all were ok (I made sure all cyl. had closed valves by turning the engine over a tiny bit) until i got to the rear cyl head and the one on the passenger side. I put about 20 psi in it and presto bubbles comming up through the cooling system. Naturally I would say its a head gasket problem and go with it.

But my dad working in a car parts store talked around and person from that store bet that my cyl that I described would be the one at fault. reason being is that the heads on my car had pourous water jackets? not sure what he ment by that but caused the coolant to eat through the head and eventually enough that im 99% sure my head is toast.

So my tip to everyone with a 3100 v6 at least the 94 gen or year.. if you think you have a head gasket problem it might not be and might need to have it pressure tested to prove if its ok.

So anyways looks like my GA might be toast and im about to post by saying any parts from a 94 GA that arent too hard to pull from are wanted to buy i can offer.

But i might get my head tested first before i just junk it.. Dont want love the car and it runs too damn good to be doing that.

Sorry for the rant just frustrated..

[rixGAphx]

Early american attempts at aluminum engine casting, in the late '50's-early '60's, had many problems with 'porous aluminum'.

That was one of the great downfalls of the Buick 215 all-aluminum V-8 of '62-'63, which was eventually sold to Rover and now sees life as the 4.2 (I *think*) V8 in the Land Rovers.
Buick had nearly a 50% rejection rate on cylinder blocks, 'cuz they couldn't find the tiny air pockets where aluminum hadn't flowed properly during casting.

The OEM 3-spoke aluminum wheels that came with my '96 GT were not only ghey, but one of them actually leaked.
No crack, no bubbles in a test bath, but the aluminum itself actually allowed enough air to escape that it lost 2 psi per week.
* * *

It's doubtful your head's aluminum is actually 'porous', since those head-casting problems were pretty much solved by the late 70's when nearly body switched from iron heads to aluminum.

BUT, the aluminum heads in the GM 60* V6 are quite susceptible to CRACKING if the engine drastically overheats and the heads warp.
A slight crack in the crown of a cylinder can allow cylinder compression to escape into the head's water jackets.

OR, the head gasket may well be 'blown', but only from the cylinder to the coolant passage an inch or so away.
Still allows cylinder compression to enter the coolant system.

In any case, the solution is a complete head job, including magnafluxing of the heads for cracks, milling of the decks for flatness, and prolly a full valve job as long as you're there.

Complete rebuilt heads are available over the net, about $360/pr plus re-usable cores.

Good luck.
-Rick

[ZACH]

^ :agree:

I had a 94 3100 and had the same thing happening. I had the heads milled and all put back together and then it worked great after that, until I blew up the tranny anyway. :lol:

Bu yeah as rixGAphx said, its very unlikely that the aluminum is porous, its more likely that the head has warped and blown head gasket, you can replace the head gasket, but it will blow a gain soon unless you get the head milled flat again.

[doobiess]

well the thing is my wife and I are looking to get a mini van so im gonna try one product and if it dont hold i think im gonna toss the car.. specially when another person with the same car said which cyl would leak pressure into the cooling system.

Either way with only 20 psi and notice a big air leak into the cooling system shows that while engine is running or under load it puts out waaay more than that and I have had the car overheat many times for the last 6 months.. also money is tight right now and I dont want to do a head job and put it all back on and find its still leaking.. either way im gonna try the wonder product and try the ceramic sealer.. if it works great if not ... well i think that it

[doobiess]

anyways im at the point that im gonna go ahead and change the head gasket and just hope its blown but if I see no signs of it gone im gonna have to just junk the car and that is what im really hoping not to do