1995 Toyota Corolla heater problem

[SecondCor521]

Hi,

I own a 1995 Toyota Corolla. My younger son was pointing out this morning that the heater doesn't work very well, and I had to agree with him. I realized I've been bundling up and chalking the coldness up to the weather, but I won't knowingly force such behavior on my kid.

The blower works fine. I checked the heat/cool adjustment thing and confirmed that it works the valve inside the firewall. The radiator is full, and the hoses look to be in good shape. No leaks of any kind as far as I can tell. I have *not* had the cooling system flushed or filled in several years. When I have the heat on max it's basically just lukewarm air that I get, even after driving the car for 10-15-20 minutes, not the nice and toasty air that one would expect and prefer to get after a few minutes. The engine temperature indicator on the dash remains motionless at the bottom of the range regardless of how long the engine runs. I think the heater might have worked well once this winter (where I got the nice toasty air that I want), but that was only one time, and currently it is doing the lukewarm thing.

After poking around on the interwebs, I think it's one of two things: A faulty thermostat, or a plugged heater core. I think I can handle a flush and fill and thermostat replacement, but the heater core thing is beyond my risk tolerance -- you apparently have to take apart the steering wheel and dashboard.

I'm trying to be frugal but I'd also like the heater fixed. Any opinions out there on whether it's the thermostat or the heater core? Any other problems it might be that I might be able to fix on my own?

Thanks!

2Cor521

 

[Westernskies]

Hi,

I own a 1995 Toyota Corolla. My younger son was pointing out this morning that the heater doesn't work very well, and I had to agree with him. I realized I've been bundling up and chalking the coldness up to the weather, but I won't knowingly force such behavior on my kid.

The blower works fine. I checked the heat/cool adjustment thing and confirmed that it works the valve inside the firewall. The radiator is full, and the hoses look to be in good shape. No leaks of any kind as far as I can tell. I have *not* had the cooling system flushed or filled in several years. When I have the heat on max it's basically just lukewarm air that I get, even after driving the car for 10-15-20 minutes, not the nice and toasty air that one would expect and prefer to get after a few minutes. The engine temperature indicator on the dash remains motionless at the bottom of the range regardless of how long the engine runs. I think the heater might have worked well once this winter (where I got the nice toasty air that I want), but that was only one time, and currently it is doing the lukewarm thing.

After poking around on the interwebs, I think it's one of two things: A faulty thermostat, or a plugged heater core. I think I can handle a flush and fill and thermostat replacement, but the heater core thing is beyond my risk tolerance -- you apparently have to take apart the steering wheel and dashboard.

I'm trying to be frugal but I'd also like the heater fixed. Any opinions out there on whether it's the thermostat or the heater core? Any other problems it might be that I might be able to fix on my own?

Thanks!

2Cor521

Sounds like the thermostat to me. You're lucky it's stuck open instead of closed.... I'd try the flush and fill/thermostat replacement, it's a simple job and will have to be done if it turns out that the heater core is plugged, anyway...

 

[73ss454]

The heater core would not make the car run cool. The thermostat is probably stuck open. Just replace it and change the antifreeze if you haven't in a few years. Make sure to use distilled water when mixing with antifreeze.

Buy the distilled water at the pharmacy as the auto parts places charge 10 X more.

Usually the heater core will start to leak and you'll have an antifreeze smell inside the car and it will effect the front defroster and the windows will fog.

 

[Westernskies]

Buy the distilled water at the pharmacy as the auto parts places charge 10 X more.

Or get it out of the cooler at the gas station like the dude in the Viagra commercial with the overheating [-]libido[/-] Camaro.

 

[Texas Proud]

I vote with the other two posts.... if your temp is low then it is the thermostat... low water temp also means low heater temp...


It is an easy fix... and easy test... pull it out.. if it is open you know.. but you can put it in a pot of water and heat it up to see what happens... or just pay the few bucks and replace....

 

[kumquat]

Well, the rest of them are probably right. IN all probability, your problem lies in the cooling system. The best part of this is that we can all tell each other how to solve the problem without dying.

 

[My Dream]

These are possible problems to your situation which I believe you've already elimated a couple items.

Low coolant level
Dirty antifreeze.
Heater core blockage
Air in your cooling system which will need to be bleed, (burped)
Defective or low temperature range thermostat, the 3 most common are 165, 180, 195 degrees.
Air mix actuator is defective or stuck.
Blower Motor weak.
Climate controls in dash are defective.
Defective radiator cap.

Based on the information that your coolant temperature gauge is not moving much, either your gauge is defective or your engine temperature is too low which can be corrected by way of a thermostat change. You can check your existing thermostat via a Google search which will tell you to place the existing thermostat in hot water and increase the water temperature while watching it open up and monitor the temperature. If you remove it and it's still in the open position then it's defective.

 

[travelover]

I think that back in the day, one could remove the radiator cap and stick a candy thermometer in the fluid. The temperature should eventually get up over 150 degrees, as a minimum. If it never heats up, the thermostat is stuck open. Does this car have a radiator cap?

Or you could do like I did as a starving college student - block the radiator with cardboard rather than change out the thermostat in a cold and wet parking lot.

 

[ls99]

I think that back in the day, one could remove the radiator cap and stick a candy thermometer in the fluid. The temperature should eventually get up over 150 degrees, as a minimum. If it never heats up, the thermostat is stuck open. Does this car have a radiator cap?

Or you could do like I did as a starving college student - block the radiator with cardboard rather than change out the thermostat in a cold and wet parking lot.

Giving away the trade secrets eh?

I ran my pickup truck with the cardboard thermostat substitute for a whole winter years ago. When spring came did the thermostat swap.

 

[landover]

But be careful, watch the temperature gauge and cover/uncover radiator depending on the weather. Once I had a blown hose due to overheating, fortunately it was near the end so I was able to reuse and fix it.

I think that back in the day, one could remove the radiator cap and stick a candy thermometer in the fluid. The temperature should eventually get up over 150 degrees, as a minimum. If it never heats up, the thermostat is stuck open. Does this car have a radiator cap?

Or you could do like I did as a starving college student - block the radiator with cardboard rather than change out the thermostat in a cold and wet parking lot.

 

[Nodak]

I would expect either a blocked or air locked heater hose, bad thermostat, or it can also be caused by a radiator cap that does not hold pressure.

 

[SecondCor521]

Thanks all.

I'm the only owner of this car, and I am pretty certain that the thermostat has never been changed.

The car does have a radiator cap, but I'm pretty sure it is fine. I took it off last night to inspect the radiator level and it was fine. Also, I was in a fender-bender that required a radiator and radiator cap replacement a few years ago, so I think that is fine.

My Dream, thanks, I didn't know thermostats came in different values. I'll make sure to get the right one.

Thanks for the recommendations on where to buy / not buy distilled water.

The defroster works reasonably well, and there's no antifreeze smell in the cabin.

I'll check the radiator temp when I get to work this morning after driving it for a short while.

2Cor521

 

[ERD50]

Agree that thermostat is the red flag. A clogged heater core might be a secondary problem, and yes, these can be difficult to get to. A word of warning on the thermostat though:

Changing a thermostat is a pretty basic DIY job. I've done it several times, no big deal. However, when I did it on our old van, the bolt holding the housing was tight. I got in there, gave it a good 'ooooomph', and it twisted off, leaving the stud broken off with nothing to grab. I got the other bolt out no problem. Long story short, I failed in my attempt to drill it out to insert an EZ-Out, had to take it to a shop for a new intake manifold

Wasn't all bad though. That van needed a valve job, so I figured while they do that work, go ahead and do the valve job. It was good to be driving a van w/o the blue smoke and acrid smell.

-ERD50

 

[My Dream]

My Dream, thanks, I didn't know thermostats came in different values. I'll make sure to get the right one.

Sometimes people take it upon themselves to change the oem temperature range to suit there needs but that's not always a good idea since on some newer model vehicles there are certain sensors that are activated at a specific temperature and if that temperature isn't achieved it won't work. In others words there maybe an emission valve that opens up at 195 degrees and if you install a 180 stat it will never activate when needed.


EDIT:

If you do change the stat don't forget to change the gasket also and make sure you bleed the system after refilling the coolant system and starting the car. Be carefull when working with coolant since water boils at a different temperture when under pressure......... If you know what I mean.

Just for curiousity purposes try putting a meat thermometer in the vent closest to the glove box and do a before and after test. I say meat since most people don't have a hvac thermometer.


Good luck.

 

[Westernskies]

Start the car up when it's cold and feel the top radiator hose; it should be cold and should feel flaccid. (and the jokes begin...) Let the engine run for a few (5-10)minutes, with your hand on the top radiator hose. If it warms up very slowly and doesn't get too hot to touch, your thermostat is stuck open- If it is operating properly, when the engine temp reaches the thermostat design temp, you'll be able to feel the thermostat open up, and a surge of very hot water will enter the top radiator hose, it will warm up quickly, become turgid and begin to pressurize the system- if it doesn't hold pressure after you feel the thermostat open, it's most likely the radiator cap.

Your heater core is just another smaller radiator, and the heater control valve is like a manual thermostat- same principles involved- but they operate secondarily off the master cooling system; it has to work properly first for the heater to work.

I'm giving Fuegos SIL 3:1 odds that your problem is the thermostat.

 

[SecondCor521]

Called the Toyota dealer - trustworthy but pricey - and they quoted me several hundred dollars for a flush/thermostat replacement. Wow. Out of curiousity I checked on the heater core and that runs $1300. Yowza.

My course is set - I will do my own flush and fill per the Chilton manual I have and replace the thermostat at the same time. Dealer wanted $20 for the thermostat.

The Chilton's does recommend the gasket replacement so I will do that. Also, I am familiar with shearing bolts off, as I did that the last time I did my own car work on this car (then it was one of the starter bolts).

I checked the upper hose when I came home for lunch just now; the top hose is hot and firm but not too hot to touch even after 10 minutes at freeway speeds.

2Cor521

 

[Dimsumkid]

Called the Toyota dealer - trustworthy but pricey - and they quoted me several hundred dollars for a flush/thermostat replacement. Wow. Out of curiousity I checked on the heater core and that runs $1300. Yowza.

My course is set - I will do my own flush and fill per the Chilton manual I have and replace the thermostat at the same time. Dealer wanted $20 for the thermostat.

The Chilton's does recommend the gasket replacement so I will do that. Also, I am familiar with shearing bolts off, as I did that the last time I did my own car work on this car (then it was one of the starter bolts).

I checked the upper hose when I came home for lunch just now; the top hose is hot and firm but not too hot to touch even after 10 minutes at freeway speeds.

2Cor521

If your car is similar to the 98 Camry setup, you might be able to replace the thermostat w/o disturbing the coolant at all. Very easy to remove/replace mine. I had the same issue you're describing, took off the thermostat and it would never close. Tested it on the stove in a pot of water/thermometer and it opened up way too early, under 100 degrees. This solved my heat issue. Hope yours goes the same, Good Luck.