Hello All,

I just want to update everyone who was so kind to respond to my inquiry above. I had my private mechanic look at my car yesterday. He said the manner in which my old radiator cap failed was common: a split develops along the edge - and is not indicative of excessive pressure.

He also said that the “bulge” that developed in the expansion tank is not indicative of excessive pressure, but age. The fact the radiator cap failed one week and the expansion tank the following week is just a coincidence and not an indication of an underlying problem involving excess internal pressure. He did not think there were as any indication that my car was suffering from a blown head gasket. His recommendation was (as some had suggested) just replace the expansion tank. I purchase a new one from my local Volvo dealer yesterday and will install it today.

Thank you to all who responded. You help keep my 3 Volvo wagons on the road.

Hugh