Noticed coolant leaking out from under the hood?

JESSEMAYR

MEMBER
2001 CHEVROLET S-10
4 CYL
2WD
AUTOMATIC
168,000 MILES

Ok. Coldest day yet. New (junkyard engine 30k miles on it) Day before noticed coolant was a little low. Driving on the highway the temp guage spiked ( I was driving a little hard) so I pulled over let it cool for a minute and dumped 3 cups of H2O in the reserve. Started it up and drove along slower. At this point the heater in the car died. Just blowing cold air. Got off at my exit and at the stopsign, the car just died. After a min I got it to kick over, but noticed coolant leaking out from under the hood (figured it was boiling and overflowing). Drove it almost 10 minutes to work, still no heat, and temp gauge seemed normal.

I'm hoping it's the thermostat. I'd appreciate any help you can give me. Thanks!

1 Reply

SQM

MECHANIC
6,383 POSTS

Hello,

It could be a stuck closed thermostat for the overheating.
First of all you need to find out where it was leaking from.
When an engine overheats it can leak coolant from various places.
It could have a ruptures hose, or it could be leaking from the radiator cap due to excessive pressure.

The over heating can be caused by water pump or a clogged radiator as well.
As you mentioned your heater quit working, which means that the coolant is not flowing thru the heater core. It could be for a stuck thermostat or could be a clog in the system.

When you have a stuck closed thermostat, there will be noticeable temperature difference between the upper and lower radiator hose, due to no coolant flowing through the engine.

https://www.2carpros.com/articles/engine-overheating-or-running-hot
https://www.2carpros.com/articles/how-an-engine-thermostat-works
https://www.2carpros.com/articles/replace-thermostat
https://www.2carpros.com/articles/coolant-leak-symptoms

The engine can also overheat due to inoperative cooling fan. Verify that your fan does come on at operating temperature.

I have attached diagrams for your reference.

Please let me know of any questions.

Thank you

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