Heater Matrix same old same old

Hi fella's.

Thought I'd share this with you.

Firstly I have a 94' N/A.

I believe my heater matrix to be blocked as I've tried topping up the system with extra coolant and it's just not leaving any room to add more to bleed any air locks.

So i'm going to remove the pipes at the join at the back of the engine just before they enter the firewall. hose through the matrix in reverse flow so it comes out of the supply pipe.

Someone then told me after it has run clear put the pipes on the wrong way round-this should over about 2-3 months reduce any extra build up. Apparently they used to do this on ford cortina's but the matrix in a cortina would pop out turn it round and replace.

Once happy that the matrix gives me hot hot hot heat in the cabin, switch back the pipes then have a full system coolant flush to replace with nice clean coolant.

Does anyone have any major concerns if I do this?

I shall be atempting this on Saturday.

Wish me luck!

Is your heater actually getting hot at all?

The heater matrix is certainly the last part of the coolant system to fill up, but I've done my coolant several times now (also 94 NA - not that it should matter). I usually fill up the expansion bottle, run the engine up to temperature, let it cool, top up the bottle, repeat a few times. The heater matrix will usually still be empty at this point.

Then I take the car for a normal run with the heater turned on full. After a few minutes (sometimes it can take a while) the heater suddenly comes on. After th car has cooled down again, re-top up the expansion bottle. Kepe an eye on it for a few days after that. Job done!

"Massaging" the heater hoses as the engine ticks over can also help.

Hmmmm, don't wish be doom and gloom, but I'd expect the heater matrix to fail shortly... (They are about the right age now ).

When I did my last coolant change (94 NA too ), I found it a real pain to get rid of the airlock which seemed to have formed in and around the heater matrix. I tried to do everything correctly, following the tips and tricks that people suggested (park the car on a hill with engine facing uphill, run the engine with the rad cap off to allow air to escape, squeeze the hoses to force air out, all of these with the heater control fully hot to open the matrix valve). I still managed to get an almighty airlock. If you look at the engine bay, the coolant filler bottle is not the highest point of the coolant system by a long shot, IIRC it's the matrix pipes at the back of the engine.

Eventually, I did it by disconnecting the pipes that lead to the matrix (the ones you mentioned), filling them up slowly with a funnel, then connecting them back up.

PS where in Hampshire are you?

We has an an air lock problem with the 200SX/RB conversion we did. I put a bleed valve up by the highest matric feed. We filled and bled the system as normal, then undid the valve with the engine running, keeping the valve open until coolant appeared. We had to drop the engine out a few times, so the valve saved us hours.

We has an an air lock problem with the 200SX/RB conversion we did. I put a bleed valve up by the highest matric feed. We filled and bled the system as normal, then undid the valve with the engine running, keeping the valve open until coolant appeared. We had to drop the engine out a few times, so the valve saved us hours.

Good idea. Any tips you'd like to share if I ever get round to foing this myself? Where did you get the valve from?

When I did my last coolant change (94 NA too ), I found it a real pain to get rid of the airlock which seemed to have formed in and around the heater matrix. I tried to do everything correctly, following the tips and tricks that people suggested (park the car on a hill with engine facing uphill, run the engine with the rad cap off to allow air to escape, squeeze the hoses to force air out, all of these with the heater control fully hot to open the matrix valve). I still managed to get an almighty airlock. If you look at the engine bay, the coolant filler bottle is not the highest point of the coolant system by a long shot, IIRC it's the matrix pipes at the back of the engine.

 

Eventually, I did it by disconnecting the pipes that lead to the matrix (the ones you mentioned), filling them up slowly with a funnel, then connecting them back up.

 

PS where in Hampshire are you?

Southampton - I'll try your solution first, what's the best way to stop any fluid being lost from the metal 'H' where I disconnect the pipes?

Is your heater actually getting hot at all?

 

The heater matrix is certainly the last part of the coolant system to fill up, but I've done my coolant several times now (also 94 NA - not that it should matter). I usually fill up the expansion bottle, run the engine up to temperature, let it cool, top up the bottle, repeat a few times. The heater matrix will usually still be empty at this point.

 

Then I take the car for a normal run with the heater turned on full. After a few minutes (sometimes it can take a while) the heater suddenly comes on. After th car has cooled down again, re-top up the expansion bottle. Kepe an eye on it for a few days after that. Job done!

 

"Massaging" the heater hoses as the engine ticks over can also help.

The supply pipes are getting hot - as in can only touch them for a few seconds before burning fingers:Pling:-the return from the matrix is cold but the return after the metal 'H' bypass is also as hot as the supply pipes:search:

Southampton - I'll try your solution first, what's the best way to stop any fluid being lost from the metal 'H' where I disconnect the pipes?

This is much easier as a 2-man job:

I think I bunged the H-piece with cloth or something when I took the heater matrix feed/return hoses off. Even if you don't do this, not much coolant will come out because it's more or less the highest part of the system in the engine bay. With both matrix feed and matrix return disconnected from the H-piece, I got some plastic tubing which fitted inside the hoses snugly and extended the feed/return lengths by pushing the tubing into the hoses: the reason for this is to allow me to get a better head of water when the feed and return are held vertically up.

From there, you can flush the matrix with hose water (moderate pressure only) in both directions.

This is where you really need 2 people, and plenty of rag to mop up spillage: with the extended feed and extended return both full of water, take out the plastic tubing from the feed and put your thumb over the hose end to stop any more water escaping. Offer up the hose end (with thumb still in place!) to the H-piece, and get it on the H-piece quick! (you can prep the metal H with a small amount of vaseline beforehand to ensure a quick fit). It's not as messy as it sounds. Repeat for the return hose.

This sounds like a lot of hassle just to fill the coolant system, and it was. Either I was unlucky with airlocks, or I was doing something wrong (although I can't think what: I've done coolant changes on other cars: they never seem to be as straightforward as people make out, but I think I know what I'm doing).

This method also means that there'll be hose water in the matrix, not coolant diluted with distilled water. Coolant+distilled water went into the rest of the system, so it shouldn't be too bad when it all circulates round and mixes.

This is much easier as a 2-man job:

 

I think I bunged the H-piece ...

Just too let you know my progress - I had ago at removing some of the pipes from the back and must have filled the matrix with at least half a litre of coolant mix. However - had hot air for a few minutes until I wacked the heater on full.

I hope to have a go at flushing the matrix next with your notes. This saturday got rained off. Think I'm running out of good weather time.

Cheers for your comments - I hope this solves my problem.

Good luck with it. I'd give you a hand, but I think I'm spreading my time too thinly at the moment

Good luck with it. I'd give you a hand, but I think I'm spreading my time too thinly at the moment

Well, I can't believe it - i only topped up the coolant in the matrix and blew down the return hose before I got rained off. And today I have heat?!:taped:I think I will leave it for now and attempt to flush the matrix much later.

The heat is not brilliant but its there on all fan settings. Do you think it might get better?

Thanks for you muchly appriciated advise.

Regards

I would leave it as it is for now: it might get a bit better. Mine's very similar: after I did the procedure I described above, my heater was warm but not super hot. I think it got a bit hotter over a few uses, but not sure.

It's unlikely to be brilliant though, mainly because the heater matrix is about 15 years old and past its best.

I have a similar problem with my heater and was wondering if it could be the heater control valve.

I have back flushed the matrix and it was flowing fine with the heater control set to its highest.

I'm fairly sure my system has no air locks as the fan was blowing red hot once I bled the system. I then turned the heater to cold and it went cold as it should. Turning the temp back up however did not have the desired effect.

Does anyone have any Idea where the valve is located so I can visually inspect it to see if its opening or not.

Cheers

Darren

It's behind the top passenger glove box IIRC. If you open the glove boxes, you should see screws that hold them onto the structural part of the dashboard (which you can't normally see). Undo the screws, and pull out the glove boxes. I think you need to do the bottom one first in order to remove the top one.

If that doesn't make much sense, give me a shout in this thread or a PM, and I'll see if I can remember any more.

After flushing the matrix, descaling, blowing, puffing and changing the water pump, put 150PSI through the matrix, and this black gunge came out. Its clear these matrix units will fill up with crud, and still pass clean water showing they are "clear". Peugot do a similar shaped hose that the Supra uses for the Matrix inflow pipe, except they have a Bleed valve. This is excellant for bleeding air out of the system.

Before pressure blowing the matrix, make sure you have put a good load of descaler / flush in it, with hot water, and let it settle and flush many times.

If you have ever had an engine filled with nontoyota coolant, (Thames Water with all the limscale in it), you will really need to flush the system, thoroughly.

I've done all the flushing out and that on mine. It works lovely for about a week and then goes cold again. Flushed it out about 3 times and does the same each time.

Do you think that could be the Air Lock problem.

My guess is that you've got an airlock that gets pushed around the system and gets trapped in the matrix.

The good news is that the matrix should be in OK nick if it works (albeit for only a week).

my heater works spot on and have no problems with it, ive just ordered coolant from toyota and was planning to change it next week, dont think its been done in a while by the looks of things. do you think i should bother with it, am i setting myself up for a headache? ive changed coolant in every car ive had and never had a problem, i just dont want an expensive nightmare right now.

my heater works spot on and have no problems with it, ive just ordered coolant from toyota and was planning to change it next week, dont think its been done in a while by the looks of things. do you think i should bother with it, am i setting myself up for a headache? ive changed coolant in every car ive had and never had a problem, i just dont want an expensive nightmare right now.

Is the coolant a rusty colour?

It shouldn't be a problem but can sometimes highlight problems that you didn't notice before. Rusty coolant could mean a damaged/faulty rad or heater matrix.

it doesnt look rusty, just a bit grubby and weak looking, want to put the proper red longlife stuff in.

it doesnt look rusty, just a bit grubby and weak looking, want to put the proper red longlife stuff in.

Putting fresh fluids in shouldn't hurt if the car is in good nick

sod it ill give it go, whats the worst that can happen

sod it ill give it go, whats the worst that can happen

Well Today I finally got round to checking the heater control valve. Visual inspection showed that when I moved the hot button, bugger all happened.

Hit said bit with a finger and yay I move the hot button and all this stuff moves and the car blows hot

Cheers Stevie_b you pointing out the location was all it took!!

As for flushing the system I used Fernox f3 and a water pump designed for use in flooded areas, very good water flow with excellent crap stripping.