I have recently replaced waterpump thermastat and a sensor that lets me see if I'm hot or cold on dash I hroke it while doung thermastat. Anyways I did all that I'm not leaking or is it hissing any steam any where but I'm still hot and irs makeing my oil preasure gadge go up and down. And then stays dwn

Seems as if I have answered this question twenty times. Remember when all the flapper doors had cables to operate them? Simple, easy and seldom failed. Your flapper doors (blend air doors) operate by vacuum and vacuum actuators now. Common failures include vacuum leaks, check valve failures and actuator failures. The fun part is you may have to remove the whole freaking dash to gain access.

If you recently had a waterpump replaced or leaking, i would say its the opti spark distributor. Main problem with the LT1 engines the water leaks all over distributor that sits behind pump causing the start no start up. When ever you change the waterpump always include the opti spark and wired connector.

You did not change the coolant temp sw. you change the ETC which sends a signal to the cpu. It looks just like the temp sw. Look on the driver side head and I believe you will see another one there or look the engine over for another sw just like the one you changed. Not sure what size engine you are asking about.

You mean the car is running fine but just No Heat?
If so
-Sound like the heater hoses are plug. or the control valve is no function

-Check the heater control valve and flush the heater unit with water of garden hose from both directions.
Q: How do I know that is working or not?
A: Slide the heater control from Hot to cold or cold to hot and check it turn or not. (If not turn at all. The cable is broken or slip off)

Mai Lor

Is it over heating, put one hand on upper hose and the other on lower hose if ther is a big difference in temperature oh my you will have to change water pump why the propellor is plastic and have a tendency to break internally. Now hold on lets go at this step by step. in the plastic radiator there is a low coolant sensor there see if that rod pops up (do this when the engine is cold) if it is you are looking at a waterpump

What about the ECT??

your thermastat went bad replace thermastat

It is possible that somehow your heater core is either blocked or airlocked. Best thing to do is to feel the two hoses that go to and from the heater core when the engine is up to normal operating temperature. If one hose is hot and the other is barely warm than you have a blocked up heater core. If you feel both hoses and they are barely warm than it is possible that you have an airlock in the system. The airlock is mostly likely to occur if you have recently had your heating system worked on such as a new radiator, thermastat, etc. If both hoses are hot then it could possibly be the heater blend doors inside the heater box could be stuck in the cold position. They are controlled from the switches on the dash. When you adjust the heat setting on the dial from hot to cold or cold to hot it moves the blend doors to either let more cold air in or more heat in. Hope this was helpful. Happy motoring.

Does the top rubber engine to radiator hoes get hot? If yes then the new thermostat is working. Does the bottom return hose from the radiator back to the engine also get hot? If yes then the pump is OK. If not then there is a blockage in the system and this will need to be flushed out from both the radiator and the engine block using a high pressure hose. Does the radiator fan come on promptly. It should start before the bottom return hose becomes hot. If not then the temperature sensor (different from the temperature sender to the dash display) maybe at fault. Your relay maybe fine but it is the sensor that actually triggers the fan to come on. It may be just bad connection so try wiggling the wires to it when the engine has got warm. The temperature sensor is also important to let the engine computer management system (ECU)know that the engine has reached operating temperature. A failed sensor not only allows overheating but means that the ECU thinks the engine is still cold and runs the engine on a rich mix. Have you noticed lumpy idling when hot and excessive fuel consumption recently? these are symptomatic of a failing sensor.

you have air trapped in the system. very hard to "BURP AIR"

park uphill on ramps if possible. With cold engine, leave radiator cap loose and fill radiator and reservoir. run engine until thermostat opens. squeeze upper radiator hose with hand. SHould be hot. Have heater on hot and blower on too. Repeat as necessary. May take several attempts.

Go here and we can help if that does not work

http://autos.groups.yahoo.com/group/villagerquest/