I just noticed today that coolant is leaking down the back of the engine. What is the likely cause and cost if I fix it myself?
Jeff

I just noticed today that coolant is leaking down the back of the engine. What is the likely cause and cost if I fix it myself?
Jeff


What side of the engine? If its passenger side, its probably the heater coolant control valve which Ive had to replace TWICE so far on my car. Otherwise there is the possibillity that it could be the oil cooler, but my bet is its the heater control valve.

It ran $200-300 parts and labor, both times at the Cadillac dealer. $53 dollar part on Cadillac-parts-dealer.com

The coolant is dripping from the bolts where the engine and transmision meet, mostly from the passanger side. I can barely see and touch the HCV. I am at the moment warming the car up to see if that is the problem. I have the facory service manual, but I can not find any info on the HCV. If anyone knows where it is or what to look under, Please help.

In the service manual the HCV is listed as heater water valve. I tried to verify where the leak was last night but couldn't, so I drove the car today but it is not leaking anymore. I topped the coolant off and crawled under the car while it was running but found nothing. The temperature outside is 10-15 degrees cooler than it was yesterday. Maybe that has something to do with it? Weird.

Mine did the same thing, was leaking slowly and intermittently. Eventually, it started pouring out, and changing the HCV took care of it. It looks like this is going to be an annual event, certainly was easier the second time! :thepan:

Run the heater and if there's a leak you will see it better

It is the HCV leaking only when the heat is off. Do I need to use new O-rings when installing the intake plenum?

Jeff