View Full Version : coolant smell/leak?


wrczx3
11-28-2007, 12:04 AM
I have been smelling coolant once in a while when I park my car but sort of ignored it hoping I was just imagining things. Today I pulled my car into the bay at my buddie's shop for an oil chancge and he told me he can smell coolant too. We looked all over the engine from top to bottom and found no leak. The coolant tank was still full also. Anyone have any problems with their XB like this?

IB-Carl
11-28-2007, 04:43 AM
Hi wrczx3!
Name is Carl. Just registered but been "lurking" since July. I too have "the smell." Dealer say's everything is OK though. There have been several other posts regarding the same issue.
I'm an "old hot rodder" having built many custom cars & engines, and have been mulling this issue over for a while to propose a theory......
The cooling system is a closed, pressurized system. When the engine heats up, the coolant expands. When the coolant expands it overcomes the pressure relief valve in the radiator cap, allowing the now "too-full" radiator to overflow into the catch-tank. When the engine (and coolant) cool, the water contracts and is siphoned back into the radiator. That's how a closed cooling system operates.
But...
The catch-tank is vented to the atmosphere so the plastic tank doesn't burst or implode as coolant moves into and out of the tank. Behind the cap of the catch-tank is a little black "teet" sticking out. This looks like a pressure relief valve for the tank. I think what everyone is smelling is the hot coolant that has been vented into the catch tank and when the tank builds up some pressure, it "burbs" coolant-smelling air under the hood. I notice mostly after coming off the freeway and parking the car. (I only live about 1-block from the offramp, so when I park the engine is pretty hot.
Mystery solved......????
Thanks for listening.

wrczx3
11-28-2007, 03:44 PM
Good diagnostic job Carl. I tend to think you are correct since if it was leaking, the coolant level would be going down. I am going to have my buddy check his all data at the shop and see if any service bulletins have been released that address this issue.

mnscionxb
11-28-2007, 08:17 PM
i have the same thing on mine

IB-Carl
11-29-2007, 04:29 AM
Evening All,
Your right...... The coolant level would go down if there was a leak, or if it was leaking slow enough not to be noticeable in the coolant level, there would have to be a drip under the car, or something evident underneath or on the side of the block, a hose, or in the radiator core.
The only other explanation would be a head gasket leaking coolant into the combustion chamber and burning it. If this was the case you would smell coolant when you open the oil-fill cap. You would also find water condensation under the oil-fill cap and on the dipstick, possibly accompanied by a milky foam colored oil on the dipstick (indicating the oil is mixed with coolant).
Hopefully a few others can confirm or debunk this theory - But I'm content it's nothing to worry about, and if it was, that's what the warranty is for!!!
Have a great day,
Carl