Car leaks coolant while AC is on?

MARYPIES

MEMBER
2001 CHEVROLET IMPALA
6 CYL
2WD
AUTOMATIC
150,000 MILES

If I use my air conditioner, a LOT of coolant drips out under the car. It is leaking near the front of the engine on the driver’s side. I can't see the leak; only the dripping coolant under the car. There is also a hissing sound. When the A/C is not on, I have a slight coolant leak, where I add about a pint of coolant every few weeks. I want to get this fixed ASAP. Any ideas on what the issue might be? If I have some idea of what the problem is, I can research repair costs ahead of time to know if I'm getting a fair price. Sadly, my trusted long-time mechanic retired & I have to brave a new shop!

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

More than likely this is a radiator leak. I doubt the leak is larger when the A/C is on but it may be getting sprayed around more because the fan is going to be on high.

Here is a guide that will help with pressure testing the system which is what we need to do in order to figure this out:

https://www.2carpros.com/articles/radiator-pressure-test

https://youtu.be/W8kra65m15c

If I am correct with a radiator issue then this guide will help with replacing it:

https://www.2carpros.com/articles/how-to-replace-a-car-radiator

Below you will find the process from the manual on how to replace this as well.

Please let us know if you have questions on this and we can go from there. Thanks

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