rob_sri Posted November 30, 2013 Share Posted November 30, 2013 I don't really want to have to swap it..! But I think that's the answer.. I just don't want to do it and find that it hasn't fixed anything as I know it is a big PITA! So symptoms are; My heaters aren't working... Lukewarm at best then it goes cold again.. Car is not overheating gets up to temp quickly and then sits bang on the middle mark I've checked the following.. Heater controls seem to be operating the servo in the passenger footwell all seems present and correct.. It's had a new thermostat, rad cap I've just flushed the coolant for the second time .. Disconnecting the two pipes that come out the bulkhead and stuck a hose in there to flush the matrix... Lots of crap like sand came out.. Kept on doing this until it ran clear i'm guessing it's designed in such a way that the heater matrix blocking up wouldn't effect the flow to the rest of the car?? So even though water is flowing through it may not be entering the matrix? I've used search etc and just looking for some help.. It's really starting to annoy me and it's getting blooooody cold!!! especially with a metal gear stick! Quote Link to comment Share on other sites More sharing options...
trebor69 Posted November 30, 2013 Share Posted November 30, 2013 Mine has just stopped warming up too , gonna start by flushing it out adding new coolant and thermostat ......I hope this sorts it out although after reading this i'm not holding my breath ..... Hope you get it sorted soon. Will you post on here when you sort it please ? Quote Link to comment Share on other sites More sharing options...
rob_sri Posted November 30, 2013 Author Share Posted November 30, 2013 Hopefully il have an answer from one many more knowledgable forum members but il let you know how I get on I have a feeling I've answered my own question but for anyone else it's worth trying all the steps above just in case .. I wouldn't be surprised if mine was blocked as the car had been standing for a while before I rescued it.. Just after another opinion.. Quote Link to comment Share on other sites More sharing options...
rob_sri Posted November 30, 2013 Author Share Posted November 30, 2013 (edited) anyone got one from here? http://www.demisterman.co.uk/Toyota/Toyota%20Supra%20Mk4%201993-98%20heater%20matrix.php *edit* I have read these don't run quite as hot as OEM.. however I dont know how fussed I am about that being as its a second car.. chances are if its really down below zero and freezing I wont be driving the car!! Edited November 30, 2013 by rob_sri (see edit history) Quote Link to comment Share on other sites More sharing options...
stevie_b Posted November 30, 2013 Share Posted November 30, 2013 I think it might not need a new matrix. If water's getting through via the hose pipe, then it's not blocked. If water's not escaping into the cabin, then it's probably not leaking. My guess is that there may be an airlock in the matrix. Several knowledgeable people on here reckon the mkiv cooling system is self-bleeding, but I've had not much success in getting the air out. In the past I've filled up the system by cracking open one of the matrix hoses (they're the highest point): not great but it kind of works. Quote Link to comment Share on other sites More sharing options...
rob_sri Posted November 30, 2013 Author Share Posted November 30, 2013 I think it might not need a new matrix. If water's getting through via the hose pipe, then it's not blocked. If water's not escaping into the cabin, then it's probably not leaking. My guess is that there may be an airlock in the matrix. Several knowledgeable people on here reckon the mkiv cooling system is self-bleeding, but I've had not much success in getting the air out. In the past I've filled up the system by cracking open one of the matrix hoses (they're the highest point): not great but it kind of works. the only thing I was thinking about this was if there was a bypass after the bulkhead to stop the heater matrix taking out the whole cooling system if it became blocked.. meaning that even with my flushing it might not be getting around the actual matrix.. im not sure how it is plumbed in behind the dash!! if this was the case then an air lock anywhere in the system too would mean that it would overheat..? its not leaking I dont think.. never noticed any water in the cabin! Quote Link to comment Share on other sites More sharing options...
wile e coyote Posted November 30, 2013 Share Posted November 30, 2013 Try flushing it both ways Quote Link to comment Share on other sites More sharing options...
rob_sri Posted November 30, 2013 Author Share Posted November 30, 2013 Try flushing it both ways have done mate Quote Link to comment Share on other sites More sharing options...
stevie_b Posted November 30, 2013 Share Posted November 30, 2013 AFAIK there isn't a bypass within the bulkhead or inner dash. When you flush, turn the heater temperature control to max: there's a small chance that this isn't necessary (depends if the temperature dial controls the coolant flow, or just the air mix). Don't take this as gospel, I'm not certain. Have a look at the workshop manual, I think it has a diagram of the coolant pipework. Quote Link to comment Share on other sites More sharing options...
trebor69 Posted November 30, 2013 Share Posted November 30, 2013 I've only had this one a year or so but it never blew hot anyway only warm and now just a warm trickle when on its lowest setting.......my brother thinks that the water pump should not be ruled out ? Quote Link to comment Share on other sites More sharing options...
rob_sri Posted November 30, 2013 Author Share Posted November 30, 2013 AFAIK there isn't a bypass within the bulkhead or inner dash. When you flush, turn the heater temperature control to max: there's a small chance that this isn't necessary (depends if the temperature dial controls the coolant flow, or just the air mix). Don't take this as gospel, I'm not certain. Have a look at the workshop manual, I think it has a diagram of the coolant pipework. I've done this too ignition on and all the way to max temp/fans For some reason I can't see it on the TSRM app under cooling.. It blew very slightly warm earlier then went back to being cold... All this time the engine didn't overheat at all completely bang on the mark Such an arseache! Quote Link to comment Share on other sites More sharing options...
Dnk Posted November 30, 2013 Share Posted November 30, 2013 Where abouts in the West Mids are you Rob Quote Link to comment Share on other sites More sharing options...
rob_sri Posted November 30, 2013 Author Share Posted November 30, 2013 Sutton coldfield mate Quote Link to comment Share on other sites More sharing options...
Dnk Posted November 30, 2013 Share Posted November 30, 2013 Sutton coldfield mate Not too far away from me What did you do when you ran the motor up after flushing the matrix ? Quote Link to comment Share on other sites More sharing options...
rob_sri Posted November 30, 2013 Author Share Posted November 30, 2013 no way where are you mate? there seems to be quite a few of us round here after flushing I replaced the hoses clamped them up topped the rad and expansion back up with water.. ran it up revved it a few times then put the cap back on and took it for a spin Quote Link to comment Share on other sites More sharing options...
TBDevelopments Posted November 30, 2013 Share Posted November 30, 2013 if your heaters are cold make sure the vent control bar hasn't fell out in the passenger footwell. Recently discovered this myself. Had 3 supras in recently and all had this issue, then found out even my own personal supra. just clipped it back in and instantly hot air Tim Quote Link to comment Share on other sites More sharing options...
Dnk Posted November 30, 2013 Share Posted November 30, 2013 (edited) if your heaters are cold make sure the vent control bar hasn't fell out in the passenger footwell. Recently discovered this myself. Had 3 supras in recently and all had this issue, then found out even my own personal supra. just clipped it back in and instantly hot air Tim Edited November 30, 2013 by Dnk (see edit history) Quote Link to comment Share on other sites More sharing options...
Dnk Posted November 30, 2013 Share Posted November 30, 2013 no way where are you mate? there seems to be quite a few of us round here after flushing I replaced the hoses clamped them up topped the rad and expansion back up with water.. ran it up revved it a few times then put the cap back on and took it for a spin Solihull so only down the rd from you. Check the part i've posted pics too that Tim mentions in the previous post Quote Link to comment Share on other sites More sharing options...
TBDevelopments Posted November 30, 2013 Share Posted November 30, 2013 good pics DNK Quote Link to comment Share on other sites More sharing options...
rob_sri Posted November 30, 2013 Author Share Posted November 30, 2013 if your heaters are cold make sure the vent control bar hasn't fell out in the passenger footwell. Recently discovered this myself. Had 3 supras in recently and all had this issue, then found out even my own personal supra. just clipped it back in and instantly hot air Tim cheers guys but this was the first thing I checked ! I was really hoping it was this too!! Quote Link to comment Share on other sites More sharing options...
TBDevelopments Posted November 30, 2013 Share Posted November 30, 2013 Quote Link to comment Share on other sites More sharing options...
Dnk Posted November 30, 2013 Share Posted November 30, 2013 cheers guys but this was the first thing I checked ! I was really hoping it was this too!! When its cold try this, Run the engine with the rad cap off, get it up to normal operating temp, set the heater to max hot, raise the rpm to around 2500 and hold for a while, then release and top up the rad as the bubbles come out, check the heater and repeat until its hot then top up rad and put rad cap back on, fill expansion tank to max level Quote Link to comment Share on other sites More sharing options...
rob_sri Posted November 30, 2013 Author Share Posted November 30, 2013 Tried this also.. Just took it down a country lane held the revs night with the cap off and let it get up to temp .. Squeezed the hoses etc replaced the cap and drove back.. Car goes up to temp doesn't overheat but heaters are freezing.. I did hear a rattle from the front a couple of times which I've never heard before so maybe my water pump is suspect.. Strange cause it hasn't overheated not even slightly.. Got a big misfire now too thanks to getting water in the bores.. Looks like il be drying it all down and WD40'ing things tomorrow too! Quote Link to comment Share on other sites More sharing options...
wile e coyote Posted November 30, 2013 Share Posted November 30, 2013 this may sound daft but Run hot water through from tap to flush through see if heaters get hot May not be getting hot from engine just a thought Quote Link to comment Share on other sites More sharing options...
rob_sri Posted December 1, 2013 Author Share Posted December 1, 2013 Not a bad shout.. Boiling water through and see what happens? Are you thinking it could be the water pump not circulating ? Quote Link to comment Share on other sites More sharing options...
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