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Cold start cooling system


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mdjaradat@gmail.com
New User

May 18, 2013, 11:56 PM

Post #1 of 5 (1173 views)
Cold start cooling system Sign In

Hey car junkies! I have a stupid question about the cooling system. On a technical level, why does the coolant in the radiator (with cap off) jump up and down when you cold start an engine? is that the coolant circulating from engine to radiator? I thought the thermostat is closed when engine is cool. And the water pump is pushing coolant away from the radiator. So what exactly is going on to make the coolant hiccup like that.


HT
User

May 19, 2013, 4:40 AM

Post #2 of 5 (1142 views)
Re: Cold start cooling system Sign In

That depends on what engine you have. Many engines have the thermostat at the return hose.




PS, you really don't want to use your e-mail address for a user name. You are posting it publicly to every spammer in the world.


(This post was edited by HT on May 19, 2013, 4:42 AM)


Tom Greenleaf
Ultimate Carjunky / Moderator
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May 19, 2013, 10:55 AM

Post #3 of 5 (1120 views)
Re: Cold start cooling system Sign In

Yes, please change that user name as if not yours would be clever to spam someone too.

As HT said thermostat could be on return not at start point. Water pump should be pumping whether it's open or not just mixing coolant inside the engine.

A noise while cold because cap is off is something else. Pressure caps are basically just to raise the boiling point of coolant needed as most operate above the boiling point but stay all liquid under pressure in normal ranges by design. Vehicles with pressure cap on radiator itself should remain air free and full all the time. If not you need to know why not,

T



HT
User

May 19, 2013, 12:02 PM

Post #4 of 5 (1111 views)
Re: Cold start cooling system Sign In

That's not what he's asking Tom.

He sees turbulence in the radiator with the cap off and the engine cold and he is expecting no circulation because the thermostat has no opened yet and that would be true if the stat was in the "input" to the radiator but if the stat is in the return side, the pump will still be pushing coolant into the radiator, just not back out, causing it to spill out the cap.


Tom Greenleaf
Ultimate Carjunky / Moderator
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May 19, 2013, 12:57 PM

Post #5 of 5 (1100 views)
Re: Cold start cooling system Sign In

OK? We don't even know what this car is yet so hard to say much on what. If everything is right except by chance seeing "turbulence" in the radiator while cold I'd chalk that up to plain vibrations from the engine running, perhaps just some coolant motion but not full flowing or maybe some bubbles get in thru a gasket.

Can't know or even guess too much on this with just that info. Noises? Eh - not really but who knows?

T







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