Expert: Rob Painter - 10/11/2010

Question
QUESTION: my heat doesn't blow hot air seams ac compressor runs when set at 90 degrees ac get cold replaced heater core thermostat radiator as the went bad also ran heater hose to intake manifold by eliminating heater control valve

ANSWER: Hello,

You have not specified year make or model.

I am concerned with the fact you state that the rdiator, heater core and thermostat all went bad. My question here would be were they all bad or if you just kept changing parts in order to guess what is wrong?

Was this engine overheated? Was this car parked for a long time?
Until I know more, it is very difficult to assist you if I can.



---------- FOLLOW-UP ----------

QUESTION: good morning, i'm sorry about that the car is a 1988 Cadillac brougham the radiator  heater core were leaking and the car had no thermostat that is why the were replaced. thank you for your help on this problem

Answer
HelloTim,

Cadillacs in that year were a little strange because you had the big rear wheel drive like I believe you have and then the smaller front wheel drive with the aluminum 4.1 engine.

I am going to assume you have the better 307 c.i. Engine.

O.K., you already left me a question from your response as to the condition of your cooling system. Why did the car not have a thermostat installed?

That tells me that someone had an over heating problem. Is the coolant jar rusty? There is a good chance you have a cooling system circulation problem, possibly rust in the water pump or cooling jackets in the engine.

If this be the case, the engine needs back flushed.

There is a safety issue for you to doing this if you have pets. Anti-freeze is very tasty to dogs and cats and will kill them.
Before the fancy flushing machines, we would take a garden hose, put it up to one side of the heater line (after heater hose disconnected) and take off the radiator cap and remove the engine block plugs and just watch the crap come out!
You may even want someone to start the engine and let it run for a little while. You do this process until only clean water flows from everywhere.

Let it drain. Reinstall the block plugs and don't over tighen. Hook the heater hose up. Install 2 1/2 gallons of anti freeze with engine running. Add water.

You should have plenty of heat if you have a 195 degree thermostat.
There is one other part you may have to have chaged and it requires a special crow's foot, but this is if all else fails. You might need what we call a dole valve (heater control valve). This valve is vacuum operated located at the passenger side of the engine. I do not want you changing until cooling system is flushed!

The legal safer way of cooling system flush is to have it done at a service center and should cost around $50. You need to do this! If the thermostat was not in the engine, previous owner had an overheating problem. There is no other reason it would not be there.

I hope this assisted you and if so, please rate.

Let me know when you get heat.


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