jackso11 Posted June 8, 2011 Author Share Posted June 8, 2011 will an airlock find its own way out through the overflow pipe in time? or does it need to be bled out? Quote Link to comment Share on other sites More sharing options...
Dnk Posted June 8, 2011 Share Posted June 8, 2011 (edited) Any other ideas on my overheating DnK? How would be the best method to bleed this system. 1. Drive car for 20 mins 2. Jack up front 3. Open rad cap 4. turn on engine 5. Let all air bubble out 6. Done Its the opening the rad cap after 20 mins driving that gets me.....won't that blow coolant everywhere? Also, is that the best method? Is there a bleeder valve anywhere? All the mkiv's ive done have been in my workshop on level ground and didnt jack them up or use a steep hill. Take the rad cap off and top up to just under the neck then run the engine till it reaches normal temp Put the heater to max hot with the engine at tickover rpm Top up the rad to just below the neck if required, check the heater If its not very hot keep running the engine but try raising the rpm up and down to approx 2000 I've found on a couple of cars doing this released the air lock and the rad level suddenly drops If this happens drop the rpm back to tickover and top up the rad Wait till all the bubbles are gone and pop the cap back on. Let it run and re check the heater and fingers crossed the heater is now properly hot Fill the expansion tank to the max level and turn the engine off Re check the rad level and expansion tank level when its cold. Keep an eye on the temp gauge while doing this but if nothings a miss it shouldnt over heat Edited June 8, 2011 by Dnk (see edit history) Quote Link to comment Share on other sites More sharing options...
jackso11 Posted June 11, 2011 Author Share Posted June 11, 2011 Ok, there was air in the system but it's out now. Changed the viscous coupling and went for a drive. All seemed good until I got stuck in traffic after a burst of turbo....temp went up to slightly over 3/4 of the way up. I also did a block/sniff test which was fine so no head gasket problem. If I put the heaters on full when it's over heating the temp drops down to normal....not ideal. Any ideas from here?? Quote Link to comment Share on other sites More sharing options...
Scott Posted June 11, 2011 Share Posted June 11, 2011 Ok, there was air in the system but it's out now. Changed the viscous coupling and went for a drive. All seemed good until I got stuck in traffic after a burst of turbo....temp went up to slightly over 3/4 of the way up. I also did a block/sniff test which was fine so no head gasket problem. If I put the heaters on full when it's over heating the temp drops down to normal....not ideal. Any ideas from here?? Still sounds like an air lock to me. The heaters on full will cool the water temp as you are taking the heat away from the matrix and into the cabin (heat exchange). You say that the air is out of the system... how do you know? Depending on how clear the matrix is etc the Supra can be a real pig to bleed. I found mine easy but I had a bit of a tough time with a mates. Remember that when bleeding you MUST have the water up to temp in order to have the thermostat open. When the thermostat is closed you are leaving the airlocks in the system and bleeding out the rad only. Quote Link to comment Share on other sites More sharing options...
skippyboyo1 Posted June 11, 2011 Share Posted June 11, 2011 my got this has been overheating for ages! good look with this Quote Link to comment Share on other sites More sharing options...
jackso11 Posted June 11, 2011 Author Share Posted June 11, 2011 Haha, it has been off the road for months. Hasn't over heated since last summer. I will try bleeding yet again tomorrow. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted June 12, 2011 Share Posted June 12, 2011 If the heater will pull the temps down it's either not enough air flow through the rad because of a faulty viscous coupling, or missing fan shroud, or the rad is not up to the job. Most alloy aftermarket ones are NOT as efficient as the very densely cored stock rads. What rad is in it? Was the replacement viscous coupling new? Is the OE fan shroud (upper AND lower parts) intact? Quote Link to comment Share on other sites More sharing options...
jackso11 Posted June 12, 2011 Author Share Posted June 12, 2011 The OE fan shroud is there, the vicous coupling was bought by a member and used for a few months then removed so basically new. The rad is a 4 yr old Toyota rad too. Quote Link to comment Share on other sites More sharing options...
jackso11 Posted June 12, 2011 Author Share Posted June 12, 2011 fan shroud is fine top and bottom by the way Quote Link to comment Share on other sites More sharing options...
Nic Posted June 12, 2011 Share Posted June 12, 2011 If it's overheated a number of times I would check the radiator end tanks for cracks. Quote Link to comment Share on other sites More sharing options...
jackso11 Posted June 12, 2011 Author Share Posted June 12, 2011 thre are no cracks anywhere, I am not loosing coolant at all, just getting too hot. What is the radiator in front of the main radiator? is that part of the aircon? Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted June 12, 2011 Share Posted June 12, 2011 I can't see mention of a new thermostat being tried. I find OE ones much more reliable in general, on all engines, that pattern parts. Toyota are now producing replacement water pumps with plastic impellers, which I don't trust as they can split and no longer turn at shaft speed and pump the water properly. If you are sure the rad isn't blocked, the rad has a sound and correct pressure cap on it, the thermostat isn't knackered, and viscous is perfect, and all shrouds are in place, I don't know what else to suggest. The stock cooling system has a huge reserve of capacity, especially in this country. The rad is the proper thick core TT one, not the thin core N/A rad, isn't it? The core of the TT one is about the same as the width of the end tanks. The N/A rad has a core a lot thinner. Quote Link to comment Share on other sites More sharing options...
jackso11 Posted June 12, 2011 Author Share Posted June 12, 2011 Yes the core is the same as the end tanks. I have put a new thermostat in last summer, new water pump (and cambelt at the same time), new rad cap, new viscous coupling, block test, pressure test and the car had a new rad 2 years before I bought it 2 years ago. I am totally stumped. How can I check if the rad is blocked somewhere inside? Are toyota replacement rads expensive? I think I might as well replace that, then everything in the cooling system is new. Quote Link to comment Share on other sites More sharing options...
Shane Posted June 12, 2011 Share Posted June 12, 2011 Yes the core is the same as the end tanks. I have put a new thermostat in last summer, new water pump (and cambelt at the same time), ne0w rad cap, new viscous coupling, block test, pressure test and the car had a new rad 2 years before I bought it 2 years ago. I am totally stumped. How can I check if the rad is blocked somewhere inside? Are toyota replacement rads expensive? I think I might as well replace that, then everything in the cooling system is new. If its sludged up, the crap normally settles at the bottom of the rad, although there's nothing to say it hasnt already clogged some of the water ways in the core elsewhere and therefore reducing the cooling capacity of the rad. Try letting the car stand overnight and from cold slowly drain the coolant, when drained remove the bottom hose and stick your finger inside the rad and see if there is a build up of sludge in the bottom of the rad, if there is before writing it off, take the rad out (easy job) and give it a really good flush with a powerful hose. On vauxhall diesels the sludge builds up in the bottom and the fan switch gets submersed in it which prevents the switch ever getting as hot as the coolant and then when in traffic it overheats as the fan doesnt come on. Yes I know the Supra doesnt really on a electric fan for cooling any build up of crud in there will be reducing the overall efficiency of the radiator. Quote Link to comment Share on other sites More sharing options...
jackso11 Posted June 12, 2011 Author Share Posted June 12, 2011 Is there an easy way to get the coolant out slowly? or an easy way to get to the tap underneath the car? Or do you need to take the under tray off? Quote Link to comment Share on other sites More sharing options...
jagman Posted June 12, 2011 Share Posted June 12, 2011 Start with the simple things: Is stat fully opening ? - it's been stood for ages Are the rubber pipes soft , are they collapsing? Is Pressure cap blowing off early ? Is the rad blocked? Is your oil level correct? Quote Link to comment Share on other sites More sharing options...
jackso11 Posted June 12, 2011 Author Share Posted June 12, 2011 all that lot is checked and fine. Thanks for the ideas though Quote Link to comment Share on other sites More sharing options...
jagman Posted June 12, 2011 Share Posted June 12, 2011 So what happened when you ran it with no stat then? Quote Link to comment Share on other sites More sharing options...
jackso11 Posted June 12, 2011 Author Share Posted June 12, 2011 I haven't run it with no stat. is that a good idea? It has been off the road but with a brand new stat and brand new coolant in it. Quote Link to comment Share on other sites More sharing options...
GINNO78 Posted June 25, 2011 Share Posted June 25, 2011 Interesting reading....any update on this ? Quote Link to comment Share on other sites More sharing options...
jackso11 Posted June 26, 2011 Author Share Posted June 26, 2011 yes, update is I have an aerotop supra that only likes to go out in the cold weather. Went out today, hot weather again....30 mins into a drive and the temp gauge starts to creep up again Hot air blowers on and the temp drops down again. So, back home and thought I would try bleeding it again. Bonnet open and I can hear the coolant bubbling away so I left it on tick over for a while with the heaters on full. It sounded like it wasn't bubbling anymore, temp gauge at normal running temp so I tried to ease the rad cap off letting pressure and steam out slowly....there was loads of steam...then the rad cap blew off and I have a red fountain coming out the front of my car I only had about 1/2 a bottle of coolant in the garage so its now not got enough coolant in. I don't know what to try next, I never use the car now as it just over heats all the time as soon as the weather is good. when the viscous fan is going if you put your hand in the bumper hole should you be able to feel it sucking air through the radiator? because I can't feel any air flow. Quote Link to comment Share on other sites More sharing options...
The-Plethora Posted June 26, 2011 Share Posted June 26, 2011 Was just about to post something up very similar. It's a hot day today, done a bit of work on the car to fix my BOV not closing properly which is sorted. Took it out for half an hour or so and all good. Parked up and my neighbour knocked on my door to say something was leaking so I head outside and there is a puddle of coolant, open the bonnet and like yours the coolant is BOILING in the expansion tank. I have a FMIC, twid rad fans and wasn't going that fast, what is the agreed upper limit for coolant temp? Wonder how BPU SMIC people are fairing. It's the hottest day of the year tomorrow and I am off to London, don't think I will take the Supra. Quote Link to comment Share on other sites More sharing options...
Scott Posted June 26, 2011 Share Posted June 26, 2011 Seriously mate, take the thing to someone who knows what they are doing. I can't believe you took the rad cap off of a fully heated cooling system...... first class stupidity right there, you're lucky your not in A&E with burns. It's an AIR LOCK. Take it to someone who knows what they are doing to remove it. Quote Link to comment Share on other sites More sharing options...
jackso11 Posted June 26, 2011 Author Share Posted June 26, 2011 Its been to someone who knows what they are doing. Its been to garages who don't know what they are doing, then with Supraloopy on here, nobody can find anything wrong with it. Bleeding an airlock, first thing people say is take it for a drive to get the temp up, then open the rad cap.....if its first class stupidity then every post on here about how to get rid of an airlock needs to be edited. Personally I always bleed from cold and just leave it running to get the temp up, but as that doesn't seem to have worked I thought I would follow peoples advise and get it up to temp before bleeding. Quote Link to comment Share on other sites More sharing options...
jackso11 Posted June 26, 2011 Author Share Posted June 26, 2011 Was just about to post something up very similar. It's a hot day today, done a bit of work on the car to fix my BOV not closing properly which is sorted. Took it out for half an hour or so and all good. Parked up and my neighbour knocked on my door to say something was leaking so I head outside and there is a puddle of coolant, open the bonnet and like yours the coolant is BOILING in the expansion tank. I have a FMIC, twid rad fans and wasn't going that fast, what is the agreed upper limit for coolant temp? Wonder how BPU SMIC people are fairing. It's the hottest day of the year tomorrow and I am off to London, don't think I will take the Supra. There must be something wrong, people run these cars in countries that are this hot all year round with no problems. Quote Link to comment Share on other sites More sharing options...
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