Boiling sounds after shutting car off

[mkmskm]

I took my car for about a 50 mile drive yesterday and it wasn't that hot (75) outside. When I parked the car it sounded like coolant was boiling in the system and there was a gurgling sound. I have a 2 year old Brassworks radiator, 4lb cap and it wasn't losing coolant out of the system at the time. When it cooled off some I checked the level and it was fine, as was the 50:50 mix. What am I hearing?

[Tom Wesenberg]

Heat soak right after shut down can cause localized hot spots. It doesn't sound like anything to worry about from what you said. When using crap gas with corn in it, the gas in the carb and fuel line will often boil also.

[Purdy Swoft]

My september 29 use to do that back in the early sixties, when I was a kid and useing a half stopped up with black pepper radiator. It didn't do any serious damage because I've still got it but it now has a new heavy duty radiator and runs cool. The 50-50 antifreeze mix in warmer temps could be a contributing factor . Straight water runs cooler. Antifreeze is said to raise the boiling point above 212 degrees. The thing is , it doesn't have to be boiling to be running hot.

[ursus]

Antifreeze, like any solute, will raise the boiling point of water not lower it. Straight water will scavenge heat better but will form steam at a lower temp that if antifreeze is used. A good "A" cooling system shouldn't need antifreeze in hot weather but some folks like the insurance it might offer.

[mkmskm]

I always use 50:50 in my old cars because most winter in an unheated garage and I don't want to take the chance of cracking a block. I wondered too if it had to do with driving a lot at higher speeds and then shutting it down without a lot of cool down time at slower speeds. I know that my turbo charged cars talk about a few seconds at idle before shutting down to cool the turbo with fresh oil.

[Purdy Swoft]

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Ursus, You are correct, That is what I meant to say and got it backwards. Sorry everyone. I went back and edited my post above. Antifreeze is said to RAISE the boiling point. Some use it year round for rust protection. I prefer running cooler with straight water and drain the system in winter.

[Purdy Swoft]

Could be clockwise backlash!!!!! Just couldn't resist. I finaly made it to 1400 posts!!!!!!!

[Ken B]

Does the Brassworks radiator require a 4#(psi) radiator cap?

[mkmskm]

I'm not sure, its just what they recommend to go with it. I imagine you could run without the pressure cap like a normal A radiator. The cap is under the hood, the top where the motometer is, is now sealed.

[johnbuckley]

Back to the original question... Crud in the waterways of the engine block?
and are all the Brassworks radiators for As like that or is it a special one?

[1931 flamingo]

The noise also may be because it's a pressurized system. Do you have a sealed overflow tank??
Paul in CT

[Tom Wesenberg]

Paul brought up a good point. I didn't think about it being a pressurized system you have, so it could be the noise of the coolant pushing the pressure cap open and flowing past the gasket during heat soak after shut down.