Air Con ice cold and no heat!

[DeTomato]

In the summer I had the A/C re-filled. All good, the A/C was nice and chilly in the heat. However, today I went out to the car to get it warmed up and switched off the A/C Auto to get some heat into the car cabin but all I was getting was cold air from the vents!

So I switched up the Temp to 29 and HOT so the cabin fan blowers were really boosting air out, but all that I was getting from the vents was lute warm cooled air. 

Is there some sort of heater switch or thermometer in the cabin somewhere that may be faulty perhaps? Any other ideas please?

[oldcodger]

Hi,

Seems if you have the rotary dial , the heat control  has a cable that operates the damper flap, so the cable could have slipped or the plastic arms broken

If its the Digital type, which with Auto I assume it is, then it could be the servo(?) motor or plastic arm that failed, viewable from under the drivers footwell, just run the temp up and down as you watch the servo motor turning

Assumes your temp gauge shows up to temp and that you haven't got an air lock if you did a coolant  change this year ?  or a  blocked heater radiator matrix which is not uncommon for 2002/3 models, well covered in the forum, basic test , do both the pipes to the matrix by the bulkhead feel hot ?

 

[DeTomato]

Thanks for the feedback oldcodger. The A/C was refilled because it didn't appear to be running cold, rather it was pushing out warm air before.

The coolant was topped and the engine temp runs up to normal; don't expect there to be air locks, unless they were there before.

I have the Digital type so I'll have to get under the dash drivers side like you say to see what is happening. Any idea how to get the lower drivers facia off? Does it pop off or are there screws - can't see any so not sure and don't want to break anything - there's no manual for my VVTL-i.

[oldcodger]

Hi,

That bottom panel,  just a flexible card type of thing with a thick foam backing, which goes under the dash and around the pedals, its held in with 2 philips screws, fairly obvious if you get down under with a good torch.

If you set things running and holding your finger on the temp up down buttons you will see the motor running and the levers moving etc.

As I understand things, there is no actual water valve controlling  the hot water flow, the levers operate a damper flap that open or closes to let the air around.

Changing the air flow setting button should activate the other motor.

However do not blame me if you do your back or neck in, its a pain to work under there !! 

Another possible problem is that the heater matrix has become blocked, the way to be sure is to switch off, disconnect the input and outlet pipes at the bulkhead in the engine bay and put on two pieces of hose pipe with  onto them, with clips etc, one connected to water and the other to drain away and see if you can  get a flow though it.

If you look on the dash,  just under and to the left the indicator stalks you will notice about 3 little slots, 15-20mm square, believe thats the cabin temp sensor, there is also one really hidden down in the a/c evaporator, but they must  be ok, if your A/C and  Climate control/Auto work ok .

[DeTomato]

With your good advice above oldcodger, I've checked the 3 slots and cleared the dust off this A/C auto sensor. It appears to work correctly when the A/C is on.

1. Having taken off the bottom dash cover under the drivers side, I was able to see the heater white lever arm moving from COLD and gradually up through 16-20 deg C to fully open. From 21-30 deg C (HOT) it is staying in the open position, presumably because more hot water will be let through into the heater matrix at 21 deg C to then heat up the cabin. Guess this is normal movement for the heater lever?

I am not sure what or where the "other motor" is that you've mentioned - is it a smaller motor above the main motor with the white lever on it? Can you clarify please as it may be this have failed or is not working perhaps...

2. I left the car running on setting HOT full fan with "Front Screen" on only (without A/C) for quite a while. Both the inlet and outlet hoses on the bulkhead are getting hot and the thermostat is operating correctly. However, I squeezed the water inlet hose at the bulk head just to see if anything would alter the heat. After a while, the passenger half side of the Front screen windscreen vent began to put out warmer air. But the drivers side is only getting warm on the inner most centre of the same windscreen front vent. As this is a Digital type "Climate Control" unit, is the warmer air on the passenger side perhaps an indication that a sensor for the drivers side is not working correctly? If so, do you know where to find it please?

And/or, could all this above indicate the heater matrix may be blocked anyway as you've suggested, or even has air in it perhaps, and therefore only half of the heater matrix is pushing heat up through the passenger side windscreen vent now? 

Be interested on your thoughts about this. With Thanks

p.s. My back aches LOL

[oldcodger]

Hi,

1.  thought mine opened more at 22-23 but then for the rest is seems to stay stationary;  perhaps thats because  the  air  temp is not changing, unlike actual motoring/heating

     As far as I remember when I looked, the other motor changes the air flow direction  according to the mode selected.

2. When testing for heat I would set the direction so the single horizontal Arrow shows and its pumping the air out of the two main central vents by the radio and Auto Off

Have read before with folk having heating problems that the passenger side can get warmer, assume that must be that the air can get out easier at that side or as you say the matrix is getting some heat on that side.    Not aware that it a dual zone climate control as you would need two setting on the controls.

3. Think it sounds like you need to unclip those matrix  hose pipes in the engine bay and attach some hose to one pipe and say using a funnel pour some water down and see if it readily flows out of the other side.

4. One thing I have read about on A/C cars, think it was an article in Car Mechanics that sometimes the damper flap, though the shaft is being turned by the motor or manual control,  the actual damper flap is slipping on the shaft and staying shut; thouggt I was getting something like that at one time, but seems to have corrected itself.

Have sent you a PM with some more info.

 

 

[DeTomato]

QQ: Do you know about how to flush the heater matrix? Does it have to be the same flow direction to flush it because of a one way valve, or can it be flushed back the other way too? Any ideas?

[oldcodger]

Hi,

In this forum there is at least one long thread, on flushing the Corollas heater matrix, though it was some years ago, cannot find it atm.

Expect there are similar ones in the other forums but have not looked at them.

Seems you can flush it both ways, no one way valve etc, and those threads do mention various household chemical used to help flush out where simple water flushing does not work.

Think you have to be careful anything used is not too aggressive and likely to cause a leak ..

Have you flow tested your matrix, does it seems blocked ?

[DeTomato]

I haven't managed to test the flow yet or flush it, but your feedback on flushing the heater matrix both ways is good news because it gives me the chance to completely unblock it, if it is.

I noted today when I had the front screen heater on, and after having the car hot running for a while going to work, was the inlet hose to the bulk head became really solid, like there was back pressure perhaps? The outlet hose was slightly less solid... Perhaps this is a definite symptom of a blocked heater matrix? Or do the inlet and outlet hoses become more solid anyway with hot water flowing in them? Any feedback from yours "not blocked"?

[oldcodger]

Hi,

Not something I noticed when checking while both pipes were hot, but will have Feel when I have been out tomorrow and got the engine hot.

I know that when its heating up you can feel one side getting warmer/hotter, but the other being cooler as the early heat was  taken out by the matrix.

Think to be sure you need to use a pair of pliers etc on those pipe clips and try a simple flow test, no need to run the engine or waste the antifreeze. they came off ok and  resealed ok using the old clips.

 

[DeTomato]

Having problem trying to flush the heater matrix directly. I need 5/8 inch pipe to connect up (think that's right but have no gauge to measure it) and then need to pour in some Radiator Flush for the blockage. I guess with the car having been standing for quite a while before I bought it, this was inevitable. I will try again next weekend. Many thanks for all your feedback so far

[oldcodger]

Hi,

Thought a standard garden hose pipe would fit with a jubilee clip ... ?  .... use some hot water to soften the end.

 Have found this thread  so if you have a good read though all 8 pages it should let you know what pipe is needed and the various methods and chemicals folk have used; seems some can really gunge up solid.

https://www.toyotaownersclub.com/forums/topic/76133-heater/

[DeTomato]

I suspect with me running my Corolla after its been standing for a while has meant coolant system sludge has accumulated in the lowest point - at the heater matrix  

Interesting a hose pipe will fit. Thanks for the tip! This makes it easier...

I looked through the thread you mention above. Very useful!

It looks like reverse flushing may be the first thing to try, running it slow initially and then building up the flow if the demand is there to push out the sludge. And other advice is to otherwise use a Radiator Flush, or Mr Muscle which I think seems rather extreme unless I can't unblock it. Personally, I wouldn't use limescale remover or anything caustic because the heater matrix is aluminium based and it will eat into the metal core and cause a leak.

And putting some WD-40 on the hoses at the Firewall to help get them off with Molegrip pliers - I expect mine will be well and truly jammed on there!  

One thought I have is my Radiator reservoir was only 1/3 full of what looked like yellow Prestone anti-freeze when I got the car. I just thought this was because it had been standing for a long time. I am in a hard water area, and perhaps topping up with 50/50 Prestone and tap water may have been enough to cause it to sludge and block up anyway?

So, I will try the reverse flush back and forth this week - we have to expect the cold weather will eventually arrive

[oldcodger]

Hi,

Perhaps some of my recent experiences may help.

Getting the hoses off the bulkhead connectors was actually quiet easy,  a twist was all they needed.

Suppose you could use wd40 but it might attack the rubber if you do not clean it all off with a spirit based cleaner like IPA.

Think you then need to see if it is actually blocked or not, if it is simple forwards and reverse flushing may work...

As for the reservoir, for years mine always dropped slightly every few months, say about 20mm,  when I did a 100k coolant change I replaced the thermostat as a matter of course.

After moving the alternator out of the way you could see some traces of dried coolant around the housing so  I though that was it, but after some months it still dropped a bit.

Could not see any other signs of leaks, checking partic around the water pump etc, but when moving the main radiator out of the way to replace a leaking a/c condenser I could see a leak right down at the front, when that was replaced its stayed slap on the mark all this year.

Think what is important that you fully flush all traces of whatever old coolant is in the engine /radiator and if you use concentrate antifreeze  its important to use distilled or RO/DI water as Hard water will just help clog things up again.  Just £1 a 2lt bottle from big supermarkets.

I use Commas antifreeze, see their site product checker for your exact model; probably G30 like mine ?

Don't know about your 1.8  as its not on all models, but on my 1.6 there is a tap at the back of the engine  quiet well hidden just above the exhaust pipe  thats there to drain off the engine block as simply removing the rad hoses may not drain it all out.  Found it with a torch and mirror but was very wary of turning the tap as though if it was seized  I might break the whole tap off the block and then would be up the creek !  - gave it plenty of Plus Gas overnight and it then moved ok.

If your does not have one, then fill with water , run to warm up and drain a good few times, using DI water for the last flush, so any water left in is not Hard water.

hth

[DeTomato]

Today I decided to tackle the heater matrix blockage.

I clamped each hose at the firewall to prevent excessive coolant loss in the engine and radiator. Disconnecting the hoses from the firewall heater matrix input and output connection was a proper challenge! In the end I used a pair of angled circlip pliers to pull the hoses back and off matrix connectors - this doesn't damage the metal matrix input output connections at the firewall.

Then I got my tubes and put one on each connector and turned on the garden hose pipe to back flush the heater matrix only. The output fluid I collected in a bucket to be disposed of.

Some brown grey fluid stuff came out which included congealed bobbles of sludge, but not really enough that I would say it could block the heater matrix. I repeated the flushing to ensure all the sludge and gritty bits were removed - about 5 buckets of water flushed through until the water ran clear with no sludge or bits in it.

Note, I didn't use ANY cleaning agents, not even radiator flush.

Reconnected the hoses, removed each hose clamp and started up the car. Left it running to 80 deg C temperature for at least 20 minutes with the screen heat on and then the internal cabin heat then on without Auto or A/C. This didn't initially make much of a difference. The front screen vent was still pushing out cooler air on the drivers side than the passenger side which was now a little bit warmer. So I thought the worst . I left it for 2 hours and went for lunch to have a think, and to let the car cool down...

When I got back to the car, I rocked it about on the driveway incline to see if I could move any air in the system. The idea I had was that air would go up to the front main radiator if I encouraged it a bit .

On getting in and restarting the engine to re-pressurise the system, sitting there I heard a lot of bulkhead burbles as air was expelled out of the heater matrix up through the pipework!

I topped up the radiator and went for a drive up the road. With this, heat began to blast through all the vents as I switched through testing them, even the front screen on BOTH sides! We have heat!

So, I believe there is one or two possible issues with the heater matrix and no heat, especially at the drivers side front screen (UK):

1. The heater matrix can get blocked because it is a low point in the cooling system. Back flushing gets rid of the sludge and gritty bits - Thanks to oldcodger for his recommendation on this

2. The heater matrix can get an air lock which needs to be expelled else it gives the effect of not warming the drivers side front screen (UK). With the all heater matrix air expelled and radiator fluid filling the gaps instead, heat is able be circulate correctly in the heater matrix to maximise its efficiency.

I'm going to check the level in the Radiator level again tomorrow, but for now I have success with heat inside the car!

[KennyKen1988]

I've just been working on this area last week for my own car, I actually required a new matrix as my original one sprung a nasty leak.

You'll know if the matrix is working because it gets very hot! The hard pipes  in the passenger footwell connecting to the matrix and the matrix itself will get too hot to touch. Before I replaced mine the heating was very poor, and upon investigation the old matrix was full of blue bits and pieces I believe from someone using incorrect blue coolant.

[DeTomato]

Yes, I think this may have been the case with mine. There were a few small globules of blue-green stuff that got reverse flushed out of the matrix. To double check, I got a thermometer and I checked the temp coming from the front screen vent and it was on 30 deg C when the digital climate heating control was set to 30 so its doing enough. However, my experience so far is there's not a lot of real hot heat coming through until the car temp gauge has got to 1/3 the way up. Once it's running at normal 80 deg C temp then the heat is there.

Otherwise, I think the radiator at the cap container end (not reservoir) is still showing some air there, but perhaps this is normal so that pressure builds in that cap cylinder and overflows into the reservoir?

I heard the heater matrix burble again today so I'm not sure I've got all the air out yet?!?!? Or does the heater matrix do this anyway when the car internal heat is put on so the coolant water is then directed into the heater matrix which causes the burbles in it?

[DeTomato]

So, I've had to top up the radiator a few times since. It appears the air introduced into the system is gradually being displaced. The cabin heating is remaining good!

[Notoyboy]

Bit late in the day to say it, but I wouldn't expect to hear any gurgling from the cooling system.  To me, gurgling suggests air where it shouldn't be, but seems your perseverence with the top-ups is paying off ☺️

[DeTomato]

Yep, it is an interesting problem when air and sludge collects in the heater matrix. Flushing the heater matrix removes the sludge, but it introduces air also as it tries to syphon back as the flush pipes are removed. Connecting all up again and persisting with coolant top ups with drives to 80 deg C appears to displace the air in the system gradually. There's no gurgles from the dash or heater matrix today . The coolant drops in the reservoir about an inch which is a good sign the air is moving out - its not leaking anywhere - I checked that out each time too