Exhaust/Gas Detection in Coolant

http://cr4.globalspec.com/thread/17105/exhaustgas-detection

If there are exhaust gases in a coolant circuit then it may be an indication that all is not well with the engine. A leak in the main head gasket will do this, and it is a fault that is best corrected early and before some serious damage is done. It usually manifests itself as a larger-than-normal drop in coolant system liquid levels and a rise in the coolant system pressure above normal (due to non-condensibles being present), and the presence of unusual substances in the engine exhausts. MoT test centres are equipped with analysers that will show this fault, and they do this by analysing the exhaust gases.

The fault appears as hydraulic etching and corrosion of the two mating metal surfaces either or both sides of the gasket. Once found, by separating the head of the engine from the cylinder block and applying the Mk1 eyeball, the repair can sometimes be as simple as building up the etched metal surface with weld metal and surface-grinding back flush, prior to reassembly of the engine with a new gasket. If severe and not corrected, the longevity of the engine and its performance will be heavily compromised and substantial replacement may be the only solution.

Correcting faults involves downtime, repairs and replacement parts, which can be evaluated so as to form the basis of an investment in maintenance. It is the justification that the manager is looking for:

• What will this equipment and its use do for the business in terms of saving repairs, maintenance hours that could be better employed elsewhere and downtime (loss of production)?
• How attractive is the equipment and its use compared with the current bank interest rate and 'doing nothing'? Is it better to buy or not to buy?
• How well does this solution compare with other solutions?

Years ago we had a problem with the radiator blowing out on a BMW 325i. A new radiator and thermostat worked one day and blew. There was no coolant in the exhaust so we originally thought there was no head gasket problem. After the second one went we started with a cold engine and a slightly reduced engine coolant level with the cap off. Running the engine with the exhaust analyzer placed in the coolant collector we detected exhaust gases. After removing the head we found the seam on the gasket had split and was allowing pressure from the cylinder to enter the cooling chamber at high revolutions, but was not large enough to allow the coolant to be sucked into the cylinder to be detected in the exhaust.

This may work some times and you might consider trying it. Be cautious about coolant temperature or possible blowback of coolant.

Short of the engine analyzer I'm not sure if theres any cheap portable units for in the field use.

Hope this idea helps.