Morzy2k5 Posted October 22, 2014 Share Posted October 22, 2014 Recently purchased my supra na.and before I got it.it had a new radiator fitted,but when I checked they had re-used the old coolant Anyway I have since changed it for genuine toyota red coolant I got 2 tubs of 5litres. The question I have is the system has bled up fine and I have warm heaters and the bottom rad hose is warm so I know there isn't any blockages.but the top rad hose doesn't really feel like there is any water/pressure in there (I can squeeze the pipe tight with my hands) and the temp gauge is normal and sits bang on half way where it should.the engine runs great.im abit stumped...is it normal to be like this? There are no leaks on the cooling system and rad cap is good. Quote Link to comment Share on other sites More sharing options...
Morzy2k5 Posted October 22, 2014 Author Share Posted October 22, 2014 Has any one got any clues?think I may try jacking it up about 4 foot at the front and leave the rad cap off and see if that helps. Quote Link to comment Share on other sites More sharing options...
trebor69 Posted October 22, 2014 Share Posted October 22, 2014 Sounds like its low on coolant in the very top of the system/hose..... Is your rad completely full and the expansion bottle up to level? Quote Link to comment Share on other sites More sharing options...
Morzy2k5 Posted October 22, 2014 Author Share Posted October 22, 2014 Yeah rad is completely full,if I try to Put any more in it just comes Out of the where I'm pouring it in.and the expansion bottle is also at the max mark. That's what is confusing me Quote Link to comment Share on other sites More sharing options...
trebor69 Posted October 22, 2014 Share Posted October 22, 2014 If the engine is warm and the system is pressurized then the hoses should also have pressure behind them and although they will squash slightly they should not squeeze shut, having air in there however will let you squeeze it closed.....I would (from cold) take the top hose clip off from the rad end then pull the pipe off and make sure its full/fill it from there.....even if only to check the top pipe is full. Quote Link to comment Share on other sites More sharing options...
Morzy2k5 Posted October 23, 2014 Author Share Posted October 23, 2014 Removed top rad hose,there is plenty of coolant in the rad...but not in the pipe? What would you suggest doing next....try re-bleeding the system as there must be a giant air bubble in the system? Quote Link to comment Share on other sites More sharing options...
Scooter Posted October 23, 2014 Share Posted October 23, 2014 Well the easiest thing to do would be to fill the pipe and reattached and brim the rad as it will have lost a bit and squeeze the top hose to remove any final air bubbles.......run it up, take it for a drive with the heater on full and then let it cool. Take the rad cap off and then gently squeeze the top hose and see if the water in the rad overflows or if you get more air out. If it keeps happening I'd suspect the rad cap even though you have said it's good. Quote Link to comment Share on other sites More sharing options...
Morzy2k5 Posted October 23, 2014 Author Share Posted October 23, 2014 That makes sense as instead of it pressuring the system the cap won't hold any pressure.i got some feeling in the pipe tonight when I had it jacked right up in the air with the rad cap off. The top rad pipe was full of water.i left it to idle for about 25mins with the heaters on full topped up coolant and replaced rad cap and drove home.once I got home the pipe was soft again and I could squeeze it. Quote Link to comment Share on other sites More sharing options...
Morzy2k5 Posted October 23, 2014 Author Share Posted October 23, 2014 Would it not over heat though if the rad cap was goosed? The engine temp is fine and doesn't rocket up and it doesn't spit any coolant out into the overflow. Once thing I can mention which may help.usualy when a cooling system is up to temp and you remove the rad cap.the coolant boils over...but on my supra it doesn't do a thing.if it's up to operating temp I can undo the rad cap and it doesn't even try and boil over/overflow out of the top of the radiator Quote Link to comment Share on other sites More sharing options...
Scooter Posted October 23, 2014 Share Posted October 23, 2014 well in the morning when cold if the top pipe is full of air instead of coolant then perhaps you have a really small pin hole in a coolant pipe somewhere? Quote Link to comment Share on other sites More sharing options...
Morzy2k5 Posted October 23, 2014 Author Share Posted October 23, 2014 It is already soft now,even though it was fine before while I was at work when I had it jacked up.by the time I was home the top rad hose was soft again.if there was a pin hole big enough for air then I think it would cause a fluid leak. Not sure what to do really.as like I say it isn't losing a drop of coolant.and not over heating.it is a strange one Quote Link to comment Share on other sites More sharing options...
trebor69 Posted October 23, 2014 Share Posted October 23, 2014 Personally I would drain the system, remove top and bottom hose and thoroughly clean pipe ends, remove thermostat then connect a hosepipe to top hose and run fresh water around the system for a while, undo heater matrix pipes at the bulkhead and run the hose through there too then blast the water out using an airline and compressor, reconnect pipes and fit a new thermostat then with front end up on ramps (shouldn't really be necessary but....) refil system and run engine (on tickover) with heater on max and full topping up as required you will need around 9 litres of coolant for this you should be able to fill the system completely and bring up to temperature with the rad cap off. I can tell when mine is full as the warm coolant heats the top pipe as it returns to the rad. One more thing to check is the passenger side footwell for water/coolant as this is a known place for heater matrix leaks. Quote Link to comment Share on other sites More sharing options...
Morzy2k5 Posted October 24, 2014 Author Share Posted October 24, 2014 ^^^ I have already done that buddy.i have given it a full flush out and added new coolant.its also had a new heater matrix it is bone dry underneath footwell carpet Quote Link to comment Share on other sites More sharing options...
Morzy2k5 Posted October 24, 2014 Author Share Posted October 24, 2014 Carried out a sniff test and all is well,I think I am leaning towards a bad rap cap and air in the system still.very frustrating Quote Link to comment Share on other sites More sharing options...
Morzy2k5 Posted October 24, 2014 Author Share Posted October 24, 2014 Problem solved...it was the radiator cap.cooling system now has pressure in top radiator hose! Quote Link to comment Share on other sites More sharing options...
trebor69 Posted October 24, 2014 Share Posted October 24, 2014 Cool Quote Link to comment Share on other sites More sharing options...
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