Heat "works" but defrost setting doesn't?

[slipkid]

Now that it's cold here in the northeast I'm noticing a problem with my heater. I have a '99 GSX with 90,000 miles. The heater/defroster used to be able to turn the inside of the car into like being on the surface of the sun. Now the heat "works" but not as strong, and the defrost setting doesn't seem to work at all and I can't melt any ice on my windows like I used to be able to - I can't feel any warm air coming out of the vents at the windshield.

I read through some threads up here and it seems like it could be something clogged (?), something wrong with the thermostat (?), or something else (?). Note that I also have a problem that I posted about in the summer, where my A/C usually won't work unless the car is moving and I wonder if this even has anything to do with that (the garage I took it to could not figure it out, in fact it wasn't acting up when it was there, and from discussions up here it sounded like it was some kind of a/c CPU thing going bad).

Just fishing for ideas and things I can try to look at before taking it to a mechanic. Any thoughts appreciated.

Seems like my car is falling apart lately with various problems - possible clutch or trans issue, had to get new front brakes, a "evaporative vent solenoid" had to be replaced, I'm getting a wierd squealing noise now when car starts up, I've got road vibrations over 55mph (which I think is due to being stuck in the mud last week).....sigh....

 

[1twistdtalon]

make sure you are not low in coolant. turn your heater on the floor setting to help burp any air out and check it again.

 

[slipkid]

make sure you are not low in coolant. turn your heater on the floor setting to help burp any air out and check it again.

THANKS I will take a look and make sure radiator fluid level is ok.

I have used the heater on the floor setting and that hasn't made a diff as far as the defroster setting though. And it seems so wierd that (a) my heater does work but (b) it definitely doesn't work as well as it used to and (c) the defroster part doesn't seem to work at all.

 

[joe sobo]

there is a cable that is hooked up to the back of them switches. it may be off. to get to it, i think you have to pull the radio bezel and radio out to get behind it to check

 

[luv2rallye]

Cardboard in front of the radiator always helps in cold climates. Also check coolant level and for a stuck thermostat or blockage in heater core. Cooling system pressure test may be needed.

 

[1993eclipseGS]

Usually are the signs of:

-bad thermostat. *easy and cheap to do*

-heater core going bad (PAIN to replace)

-low on coolant *easy/cheap*

-make sure you use 50/50 mix coolant. NEVER use straight water in the winter with these tempatures we have been having here in PA.

-cooling system problem (make sure there are NO airbubbles in the cooling system.

-Check to make sure your defrost fuse isn't blown.

You can also go to any local auto store like autozone/advanced auto and they should be able to do a free cooling system test for you. But do not let them people work on your car or touch anything else, Being alot of them have no clue about cars, Especially not a turbocharged vehicle.

 

[slipkid]

Discovered something today - not sure what this all means.

I checked the coolant level in the reservoir and it was low so I topped it off to what I *think* is the full line - I could see no markings on the damn thing to know where the actual full line is but it seemed to make sense to be at the part of the plastic before it changed shape (if I am remembering/describing it right).

I then cranked the heat up as I was driving around. I noticed that it was working MUCH BETTER than it was before. I then switched to defrost/window setting and could actually feel some warmth coming out, which I had not before doing this. But here is where it gets a bit weird...

I came to an intersection and had to stop. Usually the light changes there in like 2 minutes but for unknown reason it was all backed up. I was able to peer ahead and saw the intersection was "shutdown" with a state police car in the middle - only letting traffic flow across the road in front of me, but my road was closed - why? BECAUSE of some long funeral procession. Crazy!! Never saw that before......anyways...

I ended up sitting there for what seemed like 10 minutes (probably closer to 5 but when you are in a hurry and trying to get somewhere any delay seems like forever). And I noticed that it was all of a sudden getting cold in the car. I cranked the heat some more - IT WAS NOT WORKING AT ALL, EVEN SET ALL THE WAY UP, REGARDLESS OF WHAT VENT/FLOOR SETTING I SELECTED.

AND REALLY NUTS - THE TEMPERATURE GAUGE WENT ALL THE WAY UP TO THE RED SQUARE AT THE TOP!!!!!!!!!!! I've never seen that happen before.

And as soon as the intersection was cleared and the car started moving again, the gauge went down immediately to regular levels, and the heat came back on.

I don't know exactly what this means but am thinking something to do with the thermostat. Or could this be some kind of belt issue???? Also, this is very similar (in reverse) to my problems in the summer, where when the car is not moving, the A/C won't come on (about 95% of the time).

Usually are the signs of:

-bad thermostat. *easy and cheap to do*

-heater core going bad (PAIN to replace)

-low on coolant *easy/cheap*

-make sure you use 50/50 mix coolant. NEVER use straight water in the winter with these tempatures we have been having here in PA.

-cooling system problem (make sure there are NO airbubbles in the cooling system.

-Check to make sure your defrost fuse isn't blown.

You can also go to any local auto store like autozone/advanced auto and they should be able to do a free cooling system test for you. But do not let them people work on your car or touch anything else, Being alot of them have no clue about cars, Especially not a turbocharged vehicle.

Thanks.

About 20 years ago I changed the thermostat on my old Celica. Wasn't too hard but I had a shop manual so I at least knew where it was in relation to everything and how to get it out, how to drain everything etc. I will have to research that.

Good tip on the autozone/coolant check thing. I will ask around here at place like that or pepboys/sears/something to see if any of those places will do it.

And I did do the 50/50 mix but appreciate the heads up. I wouldn't want to be adding straight H20 in the weather we are having lately! It is effin' freezing here right now. And I need it to warm up a bit so I can wash off a ton of frozen mud that I have stuck on my wheels and undercarriage (long story)....

 

[1993eclipseGS]

I am really hoping that your water pump is not going bad...

 

[Lavery]

i herd somewhere that if you have a CEL then your computer will lower your cars operating temp as a precaution. I herd this from a teacher at a tech school for automotive technicians. Can anyone confirm?

 

[slipkid]

I am really hoping that your water pump is not going bad...

Hmmm. Guess that would be my luck of late (bunch of stuff breaking down at once). Thanks for that idea though - if that is the case it would be a waste of my time going out and getting/replacing the thermostat. Sigh. Maybe I should just take the car in and let them try to figure it out. Not looking fwd to yet another big bill.....

Thanks again for your help.

 

[KazooGS-T]

A thermostat will cost you under $15 bucks and maybe 30 minutes to install it. Is your coolant an off brown color or is it still green?

 

[Clinical]

highly advise checking your thermostat... don't want you to spend an arm and a leg for something simple by taking it to a shop if that is indeed what it is

 

[1993eclipseGS]

Agreed. Cheapest first. T-stat is 2 bolts, And 10-15 minutes to change. Do a complete coolant flush, Aswell at the same time if your coolant is old.

 

[slipkid]

A thermostat will cost you under $15 bucks and maybe 30 minutes to install it. Is your coolant an off brown color or is it still green?

I don't know the color, since I haven't drained it or anything yet (just looked in the overflow/filler reservoir).

Guess I will do the thermostat change after all, after all the comments I agree it does make sense, will hope for the best.

Thanks guys.

Agreed. Cheapest first. T-stat is 2 bolts, And 10-15 minutes to change. Do a complete coolant flush, Aswell at the same time if your coolant is old.

Is there any easier way to do the flush rather than get one of those flush kits, and cutting hoses?? I was investigating this stuff earlier tonight on the 'net and read what to do, and it sounds a bit of a bigger pain than I'd like to be doing, unless I am misunderstanding.

I do have all the tools I need to do this kind of stuff but I don't have a garage, I don't even have a driveway, and trying to do all this outside on the street in the freezing cold isn't something I am looking fwd to. I will try to pickup a thermostat tomorrow though and install that sometime this week.

Actually thinking more on it, maybe what I'll do is change the thermostat (without doing the flush unless I learn that is easier than I think), check out the existing fluid (if it is green will assume it is ok), see if the new thermostat makes a difference, then decide later whether to either try the flushing myself or seeing if a garage type place will do the flushing for cheap.

Thanks again people for all the advice.

 

[rEclipserGST]

There is a plug on the bottom of the radiator, twist it and drain the coolant. Loosen the bolts on the thermostat, change it with a new one. Retighten the bolts on the thermostat. After all coolant is drained, run water thru it. Let that all the water drain. Put the plug back in and there you go. You did a coolant flush for the price of water, a thermostat, and a container of antifreeze.

If that does not work, try putting a piece of cardboard infront of the radiator... ONLY in the Winter. Then if that does not help, it is the heater core. Good luck.

My heater core needs replaced as well, we tried flushing it

 

[slipkid]

There is a plug on the bottom of the radiator, twist it and drain the coolant. Loosen the bolts on the thermostat, change it with a new one. Retighten the bolts on the thermostat. After all coolant is drained, run water thru it. Let that all the water drain. Put the plug back in and there you go. You did a coolant flush for the price of water, a thermostat, and a container of antifreeze.

If that does not work, try putting a piece of cardboard infront of the radiator... ONLY in the Winter. Then if that does not help, it is the heater core. Good luck.

My heater core needs replaced as well, we tried flushing it

Sorry about your heater core....I feel your pain!

I had been reading/watching videos on the 'net about flushing the system and they all go through a lot more complicated stuff than what you mentioned - getting a "flush kit", draining the radiator then closing the drain valve, cutting an existing hose and attaching a T-valve from the kit to that, then attaching a hose to that t-valve, using a cleaner solution of some kind, running the engine with heater on high for like 15 minutes while hose is pumping through etc etc etc etc which cleans out the whole system. Then you drain the radiator again and refill it this time with coolant.

I'm not eager to try something like that, especially with what I noticed yesterday when I was stuck sitting in traffic for around 5-10 minutes, cranked my heat up to test it and during that time I saw my temp gauge go into the freakin' red....

Sounds like your way is just a simple flush of the radiator itself rather than the whole system?? Unless I am misunderstanding.

Dumb question #1. In old cars I've had I could add coolant to the radiator directly, and do this type of simple flush by putting a hose direct into the radiator where the cap is, but with the Eclipse the radiator does not actually have a cap on it! The cap is on the hose itself where it goes into the thermostat, not on the radiator. Wish it had the cap on top of the radiator to flush it direct. I don't think I can put the water in at the cap with the hose attached to the thermostat, because then I don't know where the water is going to be going (? into engine/thermostat vs. into the radiator itself??). If I understand your method the goal is to flush the RADIATOR itself, leave its drain open at the bottom and add water to it direct and let that run out - but to do that I think I need to disconnect the top hose on the radiator and add water to radiator there or while I have the hose off up at the thermostat end, just thread the garden hose through that hose down to the radiator??

Dumb question #2 - where is the radiator "drainplug"? I couldn't see anything looking down from the top (I think I need to change my clothes so I can crawl under there). Is it a thing that sticks out (which is what I was looking for), or am I looking for the kind that is just a screw to remove from underneath???

Dumb question #3 - since I will be working on the car when it has not been running, and it is below freezing here the past couple of days, is it even safe for me to do this flush now with water? Is there any danger of the water freezing in there rather than flushing through? Maybe I should wait until this cold freeze goes away????

Dumb question #4 - (relates to #1 with how the radiator does not actually have a cap on it where I can add fluid) - for refilling the system with a 50/50 mix when I am done flushing and have replaced the thermostat, what is the right way to do that? Do I just keep adding fluid to the side reservoir & start the engine hoping that sucks everything up to the radiator/wherever it is supposed to go? Do I try adding it at the cap on the hose?? Or what? And does anyone know the coolant fluid capacity of a '99 GSX, so that I am sure I have enough on hand, and also to know when I have added enough????

I've been doing yet more reading about this stuff, the "flush" especially and to do this right there is really a LOT more to it than just flushing the radiator out with a hose. Things like "backflushing", running the car the whole time, doing over and over to flush the WHOLE SYSTEM, using DISTILLED water rather than garden hose water, damn my head is spinning. I am afraid to try any of this for fear of mucking something up. I still don't even understand how to fill up a "closed" system like this the right way. So now I'm not even going to change the themostat, since I don't understand how to refill things right. I am definitely a "bad" gearhead. I'd rather pay somebody to do it right then me ruin my car. I'll add this to the list of things I want JNZ to do for me (trans, timing belt, waterpump), if they are OK with that.

 

[slipkid]

I now believe that this problem is the SAME one as one I posted about this summer where my airco doesn't work (most of the time) unless the car is moving.

When I started this thread I was thinking that my heat was working but not when I switched it to defrost - I realize now that my car was NOT moving when I was trying the defrost. I have noticed some hot air coming out of those vents as long as the car is MOVING. If it is stationary, after maybe 5 minutes or so, the heat stops from whatever vent setting I am using (as does airco). I've noticed this several times this week now that I am consciously testing it.

I am getting a bunch of service done this week (transmission, timing belt, the biggies) so I am asking them to take a look at this as well. I had no time to change the thermostat (or flush) yet like I wanted and am leaving that to the garage to do along with everything else. The water pump is going to be replaced as part of the timing chain service so maybe I will get lucky and this problem will be fixed with the water pump or thermostat. Or maybe they will be able to figure out what it is if it is something else. But at this point I don't think my airco problem as discussed in an older thread this summer has anything to do with the airco, or an airco computer thing at all. Whatever it is it also is screwing up my heat too.

 

[Oldsid]

Have you checked your coolant level again? The only way your temperature will go up when your heater is cold is if there is no coolant in the heater core (low coolant level in the cooling system) or if it does not move through which could be explained by a bad pump (it is about to fail but may still push the coolant at higher rpm). Check for leaks and correct than go to the next step and check you coolant pump.

 

[gpopppa]

Im going with the others with this one. Cheapest thing to do is to buy a coolant tester.Maybe 4 bucks, Check to see if you have the right mix of coolant and water. Too much coolant to water ratio will cause the heater to tweak out.I had a 96 talon with the same issue,overheat at standstill,then cool down. I took it to my brothers shop and he showed me there was way too much coolant(70/30 ish) the mechanic who did my headgasket put the coolant in.I just should of checked.

If thats not it, do the thermostat.Like you've read before easy fix.These two things would be the first things I would check.

Hope this helps!

 

[slipkid]

Thanks guys, I'll consider that stuff too.

The strangest thing is how this affects both A/C and heat, and only starts happening when the car is idling/standing still for several minutes, but not when it is moving. That makes me wonder about maybe it is some kind of fan issue (????) - when car is running the fans turn on their own right, just from the air pressure of the moving car, to a certain degree??? Maybe when the car is stopped the fans don't spin at all and that screws up the heater/ac??? I'm grasping at straws.

The car is in the shop this week for a bunch of stuff (mostly my transmission problem) and I'll be getting new water pump, thermostat, coolant put in so maybe one of those 3 things will do the trick, but if not I'm hoping they can see the this problem and figure it out.

 

[BIRDCLAWTSi]

Usually are the signs of:

-bad thermostat. *easy and cheap to do*

-heater core going bad (PAIN to replace)

-low on coolant *easy/cheap*

-make sure you use 50/50 mix coolant. NEVER use straight water in the winter with these tempatures we have been having here in PA.

-cooling system problem (make sure there are NO airbubbles in the cooling system.

-Check to make sure your defrost fuse isn't blown.

You can also go to any local auto store like autozone/advanced auto and they should be able to do a free cooling system test for you. But do not let them people work on your car or touch anything else, Being alot of them have no clue about cars, Especially not a turbocharged vehicle.

what he said.

 

[gunner87]

i got a question its a little off topic but not really bc it stills deals with the coolant. my car has never pulled any coolant out of the reservoir since i have owned it and i know it needs some. i have a new radiator bc my old one had a hole in it so i flushed the system before i changed it and it has always been on the full line. i have asked a couple mechanics but they all said its full when i know its not bc my heat was not working and i added coolant into the upper hose and it works fine now. i have replaced the hoses on the reservoir but i dont know what else to do. sorry for the long post and i know my way around cars so you dont have to explain it to me like i was new to the engine world. and thanks for the help in advance