Heater blowing warm air. Not hot.

[Sachsline]

Well as it turns out i have to drive my fwd this winter. As its getting colder, i have noticed my heater only blows warm air. Tried to source out the issue with a new radiator and hoses. New 180 degree thermostat, and new temp sensor. Still no luck. If my heater core was clogged wouldnt a symtom of that being it will blow cold air? Any other things i overlooked?

 

[Sachsline]

All hoses are hot. And coolent level is just right. Just to add to this.

 

[jakk220]

Even if it is partially clogged it could cause it to only blow warm and not hot.

 

[ErikTande]

First step is to flush the heater core. When was the last time you know the heat was working properly?

 

[lasershark]

Can also check the heater blend door if the flush doesn't help.

 

[ErikTande]

Can also check the heater blend door if the flush doesn't help.

Yeah that's a potential issue as well. Is there any way to check that without pulling the dash?

 

[Black95TSIawd]

Burp all the air out of the system.

 

[FIBA M - EC17PSE]

Bleed the system and have the heat set to full hest and fans on, as its bleeding squeeze the core hoses and shake them a little this will help move it all around it can be a pian but these cars are not actually that bad to bleed

 

[enriquez2000]

My heater sucks after putting in aluminum radiator this summer. it helped my issues over heating but on a ling drive my coolant temps are 165.. and i have 180 stat in.

When i mash boost and coolant temp goes up i get hot air from the vents...

Do you get hot air if you do a couple pulls?

 

[Diamondstartech]

Run car to operating temperature and thermostat opens. Remove heater core outlet hose and check the flow. If it seems ok I'd suspect the blend door isn't making it to full heat position.

 

[Lou98GSX]

When you turn the heat to cool knob you should hear a thud at the end of its travel . That tells you that the blend air door cable is adjusted properly and that the door is fully closing and opening .

 

[Sachsline]

I did burp the system. No air is in the system. I did check the hvac nob to see if its operating the door properly. It seems to function right and does make a slight thump sound. Although i could not see if it actually is working right. How can i with out removing the dash? If i change it to cold setting its cold and turned fully in the hot position it just stays warm. My temp gauge says a quarter below halfway fully warmed up. Its never overheated so i have not been to worried as i know the factory gauges fail. Would the temp sensor for the gauge be the issue for the cold reading and no heat?

 

[Dstarperformance01]

I had the same issue on my 1gb with 62,XXX miles. Everything in the cooling system was replaced,new sensor, new rad, new coolant 50/50 pre mixed, new pump and T-stat, flushed my heater core(as a precaution), blend door was fully seated and still had the issue. My resolution was to out a piece of card board about 12"x24" in front of radiator and it worked perfect and never over heated in 80* weather(forgot I had it in there when it started warming up). Just throwing it out as an option. I know you shouldn't have to do that, but I was tired of chasing it.

 

[Dstarperformance01]

You can use a temperature gun(like $20 at parts store) and check temp in and out of radiator and hoses also.

 

[enriquez2000]

I had the same issue on my 1gb with 62,XXX miles. Everything in the cooling system was replaced,new sensor, new rad, new coolant 50/50 pre mixed, new pump and T-stat, flushed my heater core(as a precaution), blend door was fully seated and still had the issue. My resolution was to out a piece of card board about 12"x24" in front of radiator and it worked perfect and never over heated in 80* weather(forgot I had it in there when it started warming up). Just throwing it out as an option. I know you shouldn't have to do that, but I was tired of chasing it.

Sounds like time for a bigger intercooler

 

[Sachsline]

How do i check to see if the door is being fully seated/opening? I can see a rod that connects the hvac controll to the unit and it does move up and down.

 

[Dstarperformance01]

Sounds like time for a bigger intercooler

True, that would work. It's all stock appearing at the moment. Trying to be sweet to her for as long as possible.

How do i check to see if the door is being fully seated/opening? I can see a rod that connects the hvac controll to the unit and it does move up and down.

I was able to remove rod and check with my hand for free movement and then used my borescope and was able to visually verify without much disassembling.

 

[Lou98GSX]

If your temp gauge is not at least halfway then i would think you have a bad thermostat .

 

[Sachsline]

I bought 2 new thermostats. Both made no difference.

 

[RidleyNoah]

Do as a couple of people have mentioned before you start tearing into your dash, reverse flush your heater core. It's super easy. I was having the exact same problem as you. I flushed a bunch of crap out of the heater core and now its back to normal (hot).

 

[Lou98GSX]

Flushing the heater core does make sense .

 

[Cox Abele]

I'm in the same boat with my 1995. The heat is just not enough to make this winter look enticing. My cooling system sat since 2007 until this past spring. I've done a significant amount of flushing to get the system clean, but I suspect the core is just to compacted with stuff to come clean without directly flushing it.

I've done my research and it pretty much comes down to this:

You must be logged in to view this image or video.

I don't like the idea of using compressed air unregulated as Eric did in the video. If the blockage is too strong or the core is too weak, you could potentially do some damage and rupture the core. Instead, I found that one of these little buggers fits perfectly into our heater hoses:

You must be logged in to view this image or video.

It will allow you to hook your garden hose directly to the heater hose and slowly turn up the pressure and really move some fluid through to help break down the blockage. They are sold as hose menders at any of your hardware stores, run under $2.00 and fit snuggly inside the heater hose.

Don't forget to pick up some CLR while you are there. I'm crossing my fingers in the next couple of days this does the trick- Sucks that I just finished up installing new silicone hoses and will have to dig them off again to install the old stock ones to flush through. I wouldn't want to be running CLR through my hoses unless I had to.

 

[RidleyNoah]

I'm in the same boat with my 1995. The heat is just not enough to make this winter look enticing. My cooling system sat since 2007 until this past spring. I've done a significant amount of flushing to get the system clean, but I suspect the core is just to compacted with stuff to come clean without directly flushing it.

I've done my research and it pretty much comes down to this:

You must be logged in to view this image or video.

I don't like the idea of using compressed air unregulated as Eric did in the video. If the blockage is too strong or the core is too weak, you could potentially do some damage and rupture the core. Instead, I found that one of these little buggers fits perfectly into our heater hoses:

You must be logged in to view this image or video.

It will allow you to hook your garden hose directly to the heater hose and slowly turn up the pressure and really move some fluid through to help break down the blockage. They are sold as hose menders at any of your hardware stores, run under $2.00 and fit snuggly inside the heater hose.

Don't forget to pick up some CLR while you are there. I'm crossing my fingers in the next couple of days this does the trick- Sucks that I just finished up installing new silicone hoses and will have to dig them off again to install the old stock ones to flush through. I wouldn't want to be running CLR through my hoses unless I had to.

That's the hose adapter I used. I only used water though as I read that CLR can damage the alumimum heater core. Made me hesitant to try it.

 

[Cox Abele]

Fair enough. I'm still going to give it a shot if I don't see a significant amount of sludge dump out when I'm flushing the core.

 

[RidleyNoah]

Fair enough. I'm still going to give it a shot if I don't see a significant amount of sludge dump out when I'm flushing the core.

The bottle says don't use on aluminum, but I've also read that some people have had good luck with it. Would probably be okay if you don't leave it in very long.