JimO

Very very simple one... picture/diagram doesn't show a bolt. I don't have a bolt in the hole. I'm getting a leak out of the hole. Does your car have a bolt in this hole?

Tom M'Guinn

Yes, that flange takes two bolts.

JimO

I was getting a substantial coolant leak at the back of the engine and was unable to track it down... i.e. the water hoses going into the firewall were good... and at first was petrified that I perhaps had a blown HG. Hoping that it's as simple as putting in a bolt and I'm done.

Tom M'Guinn

There is a heater valve back there that is also known to fail. Odd that you are missing that bolt...

tyro

Isn't there some sort of clamp attached using that bolt? Wire harness or the like?

Tom M'Guinn

It the cycling valve bracket.

billthe3

If you remove the cycyling valve bracket you need to either use some washers or get shorter bolts, because with the bracket not present the bolts will bottom out before the hose flange is tight against the head.

333pg333

Is this the hole that some people talk about regarding redirecting a secondary flow or pump to help circulate coolant better?

blown 944

No Patrick it is just a bolt hole to attach the rear coolant tube/bracket.

PM Josh as he found a 3 way valve to take the place of the 2 way heater shutoff. That would allow some coolant flow to the rear of the head w/o having the heater on. However it won't eliminate the air pocket IMO. Coupled with a steam vent kit though, I could see it working well.

fbgh2o

If you have removed the flange, you will also want to replace the gasket... (ask me how I know)