Heater blowing cold

[landin]

I have a 91 EX coupe. The heater blows warm but not hot. The cable for heater control is fine. The thermostat is new. The coolant is full. Car operstes at a constant normal temp. So....why am I not getting warm enough air to heat the car?

[deevergote]

Your heater core may be clogged. Have you ever put any sort of "stop leak" product in your radiator? That is very often the cause of a clogged heater core (though far from the only cause.)

[honda_mike]

iam having the same problem at the moment, but now its starting to blow out a little warmer then cold, check your lines that run into the firewall and feel if there hot, if one is and the other isnt then theres a possibility of a blockage. I 've gotten advice from here about mine, its just a process of elimination

[landin]

It will warm up if you hold it at 2000+ rpms so I am thinking a water pump or heater core. I have never put any stop leak in but it does have 150k on it and I just bought the car.

[toycar]

Well wait a minute. Are you saying the car will warm up if you hold the idle, or the heat gets hot?


Two entirely different issues there man. If your heat isnt hot, try the following;

-Check the lines, as mentioned above if one is hot and one is not your core may need some loving. Basically, take it apart, remove it from the car, hook up to air compressor, reduce PSI to 25-30 and blow through core for 2-3 minutes. Should help.
*You might also have to burp the coolant as sometimes in this time of year, if the coolant is old and shitty there may form a bubble in the system-causing this to happen.

-Check your overflow tank. Not the radiator, but the overflow. If its not full to the required spec, you will get no heat.

-Check to make sure the cable is actually opening the valve. Just because the cable is intact, and works seemingly flawless by the touch, in the car, doesnt mean its really working under the hood.

Good luck. If none of this helps, I dont believe you... Lol

[honda_mike]

Well wait a minute. Are you saying the car will warm up if you hold the idle, or the heat gets hot?


Two entirely different issues there man. If your heat isnt hot, try the following;

-Check the lines, as mentioned above if one is hot and one is not your core may need some loving. Basically, take it apart, remove it from the car, hook up to air compressor, reduce PSI to 25-30 and blow through core for 2-3 minutes. Should help.
*You might also have to burp the coolant as sometimes in this time of year, if the coolant is old and shitty there may form a bubble in the system-causing this to happen.

-Check your overflow tank. Not the radiator, but the overflow. If its not full to the required spec, you will get no heat.

-Check to make sure the cable is actually opening the valve. Just because the cable is intact, and works seemingly flawless by the touch, in the car, doesnt mean its really working under the hood.

Good luck. If none of this helps, I dont believe you... Lol

Toycar is right about checking for a burp and the cable, i havnt heard about the overflow tank. Still have to check that one on mine, still have no heat lol, but like mentioned check yor lines, burp the coolant and check the cable, just pary that you dont have to do a heater core

[landin]

The car always runs at a constant normal temp. The heater will warm up if the idle is held at 2k or more. I have checked the cable for the heater control and the valve on the firewall is working just fine. How exactly do you "burp" ? I have also done this a time or two but you may know a beter way. I am starting to think it is a weak water pump.

[honda_mike]

The car always runs at a constant normal temp. The heater will warm up if the idle is held at 2k or more. I have checked the cable for the heater control and the valve on the firewall is working just fine. How exactly do you "burp" ? I have also done this a time or two but you may know a beter way. I am starting to think it is a weak water pump.

there could be a slight possibility that it is a weak water pump, but like i had mentioned before mine does the exact same thing but itll warm up a little bit not alot at idle, i dont have to reev it to 2k, both the lines going into the firewall are hot?

[No Name13]

my car did this...turns out my knob was broken...the back of the knob looks like a "D" but the straight part had broken off so it would't grip..and the knob doesn't spin all the way around even if its broken.. its pretty deceiving

[landin]

Noticed a leak at the water pump today. I will replace that and I'm sure the heat will work!

[honda_mike]

that i have not noticed, but started checking out a few things and all hoses are hot, started reving like u did and got a little hotter