At the point that they work you do not need much diagnoses. They detect
hydrocarbons so you will also need some level of combustion failure for the
hydrocarbons to get into the coolant.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Jason
Sent: Thursday, October 31, 2013 10:17 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Head Damage?

Get some coolant test strips.  You can test for exhaust gases in the
coolant.

Jason

On Thu, Oct 31, 2013 at 10:13 PM, Dennis Haynes
<d23haynes57@hotmail.com>wrote:

> Combustion gasses getting into the cooling system can be a cracked
> head or more commonly the heads are actually loose. Under load they
> are lifting off the cylinders and letting gasses into the cooling
> system. In the air cooled days you could actually hear loose heads.
> Often it sounded like an exhaust problem.
>