Expert: Rob Painter - 11/18/2010

Question
First, Id like to say thanks for doing this. I have briefly read over some of
the q & a 's and they seem to be very helpful. I bought this cadi about 2
months ago, believe it was sitting (63018 -milage). The first issue I
noticed was the heater core, coolant leaking from under the car upon
shutoff as well as little to no heat. I brought the coolant level up to
normal and when activated the heat would blow for about 5 secs before
turning cold. This was about a month and a half ago. Now with the
colder temps I need the heat to stay on and its just blowing cold with an
adequate amount of coolant. The only diagnosis I've done is removing
the glove box liner to observe the arm moving back and forth according
to desired temp. I also no longer see the coolant leaking under the car
as much. Can u help please  

Answer
Hello,

Thanks for writing. Like the person in which I answered his question on a related last night, I have grave concern about the condition of this aluminum engine. It can never be overheated or it self destructs with temps above 230 degrees f.

I hope you did not buy a car with a bad engine. Any type of leak to the coolant system causes overheating and the potential for blown head gaskets and more. Used engines for this car can be considered junk and not available because they are known for overheating issues. Your leak may be coming from a cylinder head and not the heater, which would explain your no heat issue. For the heat to work, the radiator must be full and pressurized.

You need to go to a service center (not the dealer) and have the system pressure checked and find out exactly where the leak is and get back to me. You may have been sold a lemon. Usually, a leaking heater core problem shows the problem inside the cabin. The hoses are easy to see under the hood. If the coolant is leaking on the side of the engine, you have a blown head gasket or cracked block. If so, not worth repairing because you don't know any other damage done. You may need to stick $5,000 for a brand new engine from Cadillac. Find the leak first and we will go from there.

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