I don't even pretend to know a lot about cars so from the beginning I am assuming I am talking about a a heater hose. Just before going into the firewall on my 87 Volvo 740GLE from the engine compartment there are two 1 inch or so hoses the bottom hose has a valve that seems to be operated by air preasure. At any rate the valve broke at the hose and since it is Saturday with no dealers open I can't find a replacement so I just removed the valve and coupled the hoses together where the valve normally goes. I can't see where the valve serves any purpose. I Put new anti freeze in, started car and let run for awhile with the cap off of the radiator overflow tank and it seemed to work fine. Then I put the cap on the over flow tank and within 5 minutes it overheated. Could it be that just by some quirk the theromostat also went bad just at this very moment or does by passing the valve in some way cause this to happen. Thanks very much for any help you could give.


Thanks

CK

PS I just started the car again and let it run for 30 minutes with the cap on the overflow tank and now there is no overheating. Could it just have been a sticking thermostate?