Coolant cap untwisting itself, why?

[4g63tcrazy]

If the cap twists off a little it will make it easier for the coolant to push into the overflow. Bad HG or not..

[desolate]

Try one of the square coolant caps that comes with a red lever to release pressure. Knew a guy who was seeing the same problems but the square cap did the trick.

[Pushit2.0]

The cooling system is designed to be under pressure to raise the boiling point of the water in the cooling system. If the cap is loosening, this will in turn lower the pressure at which the cap will allow coolant into the over flow tank. I would try to secure the cap and see if you still push coolant. If I recall your car would hit MBT before the knock sensor would show anything threw LINK.

~John

[turbotalon1g]

Thx guys I will it out and see. I just the car drivable till I get home in may

[deadeye]

1+ the locking lever vent rad cap. Oreillys carries them and they work great. It will not come unscrewed without the lever being flipped up.

That being said I do concur with the others on here that its probably worth doing a cooling system pressure test just to be sure there isn't a underlying problem.

[turbotalon1g]

Ok, just got back from the field. suckfest no shower for 4 days.

Um, did a coolant system test, lower hose slightly dripped, fixed leak. Test drive at 25psi, same thing pushes coolant.

I have limited time (I leave here next week and maybe have saturday to work on the car) and limited experience doing HG jobs, also limited tools. Anywho, u guys think it would be worth throwing in a new set of ARPs and a stock HG?

[turbotalon1g]

Me=dumbass, what i meant by that last question is, could i do a hg without getting the head milled/block decked?
I don't have the time since I have to leave in a week and i can basically only do it on saturday, or will it be a complete waste of time to just slap a new HG and studs in there?

I'm thinking its worth a try.

[blackrosenova400]

Get a straight edge and a feeler gauge to check the head and block when you pull the head. Id say nothing over .002 and you would probably be fine with a composite gasket.

Me=dumbass, what i meant by that last question is, could i do a hg without getting the head milled/block decked?
I don't have the time since I have to leave in a week and i can basically only do it on saturday, or will it be a complete waste of time to just slap a new HG and studs in there?

I'm thinking its worth a try.

[FattyBoomBatty]

Reminds me of my engine, except the cap wouldn't twist off, it just lifted the head and put horsepower into the coolant. Sprayed everywhere.