Attached is a pic of a hose and some valve or something that I am unfamiliar with. I think it is part of my rear ac. Looks like there is uv dye on it and I think this be where my leak is. I can't identify it and I can't seem to find a reference to it in my repair manual. Can someone identify it?




Thanks in advance.

 

That is the hot water control valve for your heater core. The dye may be because someone was trying to find a coolant leak. With the engine running, have someone inside the cabin move your temperature selector from hot to cold to hot and you'll see the mechanism working. If it's leaking, they aren't too expensive or hard to replace. Any time I put new heater hoses on, I replace it too as the plastic gets brittle with age and can snap, dumping your coolant.

 

Ah, thank you. Would testing it produce results if the heater has never worked? Should the valve still move if it's not faulty? Thanks again for the response.

 

If it's stuck shut, your heater won't work anyway. It's not an expensive part. I think when I replaced one last winter on my Escalade, it was around $15. Drain your cooling system and unhook the hoses and pop it in. Refill and you may have heat now.

 

Thanks. Ill change the hose and valve soon. Any idea how I have uv dye on the valve if the hose runs coolant? I don’t see how dye would get to that valve.

Thanks.

 

There are different dyes to look for leaks. There is an oil based dye you put in engines and transmissions, a refrigerant dye for the a/c system and a water based dye for the cooling system. Dyes weren't in general use when I was in school but they really save time hunting a hidden leak. The glasses and UV light are cheap and pay for themselves the first time you use them.