My girlfriend just bought a stock 89 Si. High mileage, never modded. 4 hours after picking it up I tried the heat and it won't blow warm. I know nothing about heater cores or whatever. What should I check?

 

Is the fan working? You can go underhood and look at the heater hoses and see if when someone adjusts the cold/hot **** if that valve it moving. I would also suggest a reverse flush on the heater core as you might have something stuck in there.

I don't know if it is a wise idea or not but I have thought about removing the heater hose from the motor and running some CLR in there to remove build up. I have not done it yet though, I have a CRX that hasn't had heat for 4 years and it does get a little cold at VIR in Feb when it is snowing on track with the windows down.

 

Assuming that your blower is working.

The hot/cold **** controls two things, the valve under the hood and a valve that you can see if you look under the dash on the pass. side behind the radio area.

This thread has pics of the locations. (scroll down)

https://honda-tech.com/zerothread?id=1780678

When you turn the **** from cold to hot or vice versa, see if the valves are moving.

If you cant get heat then, there might be a clog in the cooling system.

 

Check the mix valve like stated above. If it takes a long time to get to operating temperature, it could be a bad thermostat as well.

 

Thanks guys, I'll check it out when I see my gf.

When I turn the **** from cold to hot it only has tension for about 2/3 of the way. I can feel a little bit of heat but not close to enough that it would warm the car.

 

vavle is probably bad or the cable is kinked