Heat problem

[rdcjg27]

i was lookin threw the Sticky on this, and at the end it said something bout the lever that lets the valve open on the Heater Core....see 90 festiva will get up to temperture on the guage, but no hot air just warm air, Top radiator hose is warm but not extrememly hot, and lower one is cooler than top one, then both heater hoses or not warm at all?
but dont want to spend $20 on thermostat if that aint hwta problem is...
i saw this bout this lever and thats got me curious...
any help will be apprieacted,
also i cann tell when thermostat opens cause temp guage goes down?

[WmWatt]

My temp guage does not go down when the thermostat opens. I have a piece of masking tape with a mark on it taped to the guage. You can test the thermostat by removing it from the car and immersing it in hot water to see if it opens. That's a bit of a job because you have to drain the fluid but $20 is $20.

[TominMO]

You probably have a clogged heater core. John and I have wrestled with this on my 323. In this weather (under 10 degrees), I can get the motor to properly heat up only with a piece of cardboard covering all or most of the radiator. Gauge goes to about the middle. But no real heat comes out of the heater; in fact it was coming out very cold this morning.

So today I replaced the thermostat. The old one was a 180; the new one is a 195 Stant. Now the temp coming out of the heater is between cool and lukewarm, but not supercold like before. So the thermostat helped, but there is probably still blockage in the heater core. I'll try an aggressive flushing effort this spring. I can live with cool/lukewarm for now, esp. since I have other cars to drive that heat well.

Using radiator flush might help; it has helped my car, but there's more to do.

[resuwrecked]

Get the engine hot, then feel the heater hoses where they go into the firewall.
If they are both cold, you have an air pocket, let the engine run w/ the rad cap off (be careful and smart about it cause im not liable for you hurting youself) let it burp the air out. keep it topped it off.
Make sure you have a good radiator cap so that as the engine cools it can suck coolant back into the radiator from the expansion tank as it cools.

If the inlet hose is hot and the outlet is cold, then the heater core is clogged.

You described your hoses as not being too hot, and the heater hoses as not being warm at all. with the engine at temp your upper rad hose and hc hoses should be hot to the touch. Your rad fan isnt running constantly keeping it cool, is it? if your fan switch (one wire sensor looking thing near t-stat) is bad it will make it run all the time.

[TominMO]

Get the engine hot, then feel the heater hoses where they go into the firewall.
If they are both cold, you have an air pocket, let the engine run w/ the rad cap off (be careful and smart about it cause im not liable for you hurting youself) let it burp the air out. keep it topped it off.

When doing this, make sure your heater is on (not the fan necessarily, but the cold-hot selector switch should be on hot). And try to park so that the rad filler hole is uphill, so bubbles will naturally rise to that point.

[resuwrecked]

It doesnt matter what the temp selector is set to, all it does is control the mode door. there is always hot coolant circulating through the heater core. There is no bypass valve on our cars.

[TominMO]

It doesnt matter what the temp selector is set to, all it does is control the mode door. there is always hot coolant circulating through the heater core. There is no bypass valve on our cars.

Interesting. Didn't know that, thanks.