coolant leak only after using the heater

mrbill65 · #1 (**permalink**) 10-29-2011, 08:06 PM

Anyone ever experience a coolant leak after using their heater. The strange thing is I can not find the leak. It only leaks after the truck cools down. I have searched for the leak with engine running after shutting it off. I can't find the leak. The only evidence of the leak is when I come out from work there is a small puddle of coolant under the truck. It is driving me nuts. No coolant under truck when using ac. any clue as to what is happening? This has been going on for a year or two.

2007 4X4 nismo
99,680miles

Mrbill65

**bwarren228** · #2 (**permalink**) 10-29-2011, 08:41 PM

Where under the truck does it puddle up? My guess would be near the firewall based on what you have said. It has to do something w/ the heater hose assembly or heater core. Since you see the puddle on the ground, I'm thinking it isnt the heater core because that would leak in the truck

**Zero Six LE** · #3 (**permalink**) 10-29-2011, 08:47 PM

Do you smell coolant inside the truck while using the heater?

mrbill65 · #4 (**permalink**) 10-29-2011, 08:59 PM

no coolant smell in cab. coolant on ground on passenager side of truck up around the front of the front tire.

**Zero Six LE** · #5 (**permalink**) 10-29-2011, 09:01 PM

Quote:

Originally Posted by mrbill65

no coolant smell in cab. coolant on ground on passenager side of truck up around the front of the front tire.

It must be coming from the recovery tank if that's the case. Maybe your cap isn't holding the correct pressure or is not fully tightened.

Mylt1 · #6 (**permalink**) 10-30-2011, 10:28 AM

buy a dye kit.

**Zero Six LE** · #7 (**permalink**) 10-30-2011, 10:34 AM

Check the hose that connects the radiator to the coolant tank. That seems like a like place for a leak.

Mrtoadzwildride · #8 (**permalink**) 10-30-2011, 11:59 AM

If it is your heater core, you will typically have a film of Glycol on the inside of the windshield.

Personally, I would clean the underside of the vehicle really well, run the heck out of the heater and park it in a garage where you can watch for the leak. Also, check where your hoses go through the firewall to your heater core.

Let us know what you find the problem to be. Pictures always help... Just sayin'

vedder012 · #9 (**permalink**) 11-20-2012, 10:38 AM

Sorry to dig up a year old thread but I'm just wondering if the op solved his problem. I'm having the same issue where my truck will leak coolant after my truck cools after using the heater. Doesn't leak unless I use my heater. It's not a fast leak, after a few days of the truck sitting the puddle will be about 10 inches diameter. The puddle normally builds under the front diff. I replaced 2 hose clamps on the main large hose that goes into he bottom right of the rad and at the other end where it connects to the motor?? When I looks from under the truck I cannot tell where it's running down from.

I noticed this happening since the weather has changed, I know sometime the cooler weather can mess with the hoses and clamps.

Thanks

Gonzo's SV 4x4 · #10 (**permalink**) 11-20-2012, 10:56 AM

Heater core, located inside the dashboard. That's about the only thing that comes to mind.