Heater does not blow hot

[brider1]

I am a newb when it comes to smaller compact cars. Trying to fix my girlfriends 98 carolla, it is much different then my 76 chevy pickup . Any help here would be great. The heater will not blow hot at all. I thought maybe the heater core needs to be replace but not sure? any suggestions?

[90 GP]

Is the temp gauge reading in the center positon when warmed up? Do both the inlet and outlet hoses that go to the heater core feel warm to the touch? If not try replacing the thermostat and back flushing the cooling flush and add new coolant. If unfamiliar with location of thermostat check out a Haynes manual at your library or parts store. Not sure where your stat is located on your car. On my 90 it's on driver side where the lower hose from radiator enters a housing that has sensors with electrical connectors on top. If you replace stat make sure the air burb valve on stat is oriented so that it is at top when you reassemble.

[96_9c1]

[quote=90 GP]Is the temp gauge reading in the center positon when warmed up? Do both the inlet and outlet hoses that go to the heater core feel warm to the touch? If not try replacing the thermostat and back flushing the cooling flush and add new coolant.quote]

If the feed line to the heater core is warm and the return line is cold, you have a clogged heater core. Place a garden hose on the return to back flush the debris that cant make it through. Or if its too cold for the garden hose, you can simply blow all the debris out using your mouth I know it sounds gross, but thats the simplist way I got to say it

If the car wants to overheat, you may have a stuck closed thermostat. Also the return hose off the block will be cool, if this is so.

If the needle on the temp gauge stays low, and takes forever to warm up, then you have a stuck open theremstat.

The only time I've seen that a heater core needs replacing is when its leaking on the pass. side floorboard.

You maybe able to pull some information off Autzone.com, to find the location of the things your on sure of.

[brider1]

the temp stays right in the middle where is is supposed to be, i will check how the hoses feel going in and out but it sounds like it may just be blocked up with junk.

[thisxstyle]

Make sure you check the heater bypass valve too, that has been the culprit for me before.

[diver9000]

Originally Posted by brider1

I am a newb when it comes to smaller compact cars. Trying to fix my girlfriends 98 carolla, it is much different then my 76 chevy pickup . Any help here would be great. The heater will not blow hot at all. I thought maybe the heater core needs to be replace but not sure? any suggestions?

The easiest thing to check is the water level in the radiator. No water, no heat. Then try swapping the thermostat. The heating system is exactly like your chevy truck. The heat works in the same way. Radiator to the thermostat to the heater core etc....

[ghost_ryder35]

you should also check to make sure that the temp selector wire is not broken either under the dash or in the engine bay. The temp selector could be stuck on cold which is why there is no heat blowing.

[thisxstyle]

The thermostat should have nothing to do with the heater. It is just a send and return line from the block.

It's the same reason your heater gets warm before your temp gauge shows the engines warmed.

[diver9000]

Originally Posted by thisxstyle

The thermostat should have nothing to do with the heater. It is just a send and return line from the block.

It's the same reason your heater gets warm before your temp gauge shows the engines warmed.

How do you think the water gets hot? And when the water gets hot, what part do you think opens to allow the hot water to flow to the heater core? Yeah the thermostat.

I do agree with ghost though, I would also check the heater cable (wire).

[sambojoho]

Originally Posted by diver9000

How do you think the water gets hot? And when the water gets hot, what part do you think opens to allow the hot water to flow to the heater core? Yeah the thermostat.

I do agree with ghost though, I would also check the heater cable (wire).

Nope, the thermostat opens to send flow to the RADIATOR.

However, I disagree that the thermostat has nothing to do with the heater. Problem is, if the thermostat is stuck open, your coolant will never get up to temperature.

[ghost_ryder35]

Originally Posted by sambojoho

Nope, the thermostat opens to send flow to the RADIATOR.

However, I disagree that the thermostat has nothing to do with the heater. Problem is, if the thermostat is stuck open, your coolant will never get up to temperature.

Brider says the temp guage is at the correct level, so the coolant is getting up to temp. sambojoho let me drive your car, bet i could not only get it up to temp with a stuck open thermostat, but also get it to over heat (just trying to be an ass sorry)

[Flashmn]

what part do you think opens to allow the hot water to flow to the heater core? Yeah the thermostat.

Heater inlet bypasses the thermostat.

[thisxstyle]

http://auto.howstuffworks.com/cooling-system10.htm

Back to basics?

[diver9000]

So whats wrong with it?

[diver9000]

Originally Posted by diver9000

How do you think the water gets hot? And when the water gets hot, what part do you think opens to allow the hot water to flow to the heater core? Yeah the thermostat.

I do agree with ghost though, I would also check the heater cable (wire).

OOPS. I wrote it backwards. I know what I meant though. LOL