Hi Andrew, 

        Thank you for posting this.  Both for the good info, and because I didn’t see John’s message on list or in my junk.

I once had air build up in my 1.9 reservoir.  Dennis Haynes suggested we try to torque the heads before I did anything else.  That worked and the engine is still running today powering a friends now water cooled Bay window.
But, this was some air in the reservoir not blowing off a cap!

John, what 2.1 are you working on? 

Any updates on your tree loving 91?

Eric Caron 

> On Jul 7, 2024, at 5:11 PM, Andrew Berg <andrew@BERGWEB.CA> wrote:
> 
> If you're driving and this happens, immediately crank your rad bleed screw a little. If a lot of air hisses out before coolant, then you likely have a bad fire ring. You can confirm with a block test kit to check for combustion gas in coolant. Sadly I encountered this and an currently rebuilding my engine.
> 
> Andrew
> 
> On Sun, Jul 7, 2024, at 4:52 PM, John Rodgers wrote:
>> When the pressure cap blows off the coolant tank and coolant is lost, sure
>> sign of blown gasket, Right? 2.1 L