straightsix Posted May 9, 2011 Share Posted May 9, 2011 I've done a search but can't find anything useful.... Went for a blast in the Supra (N/A Auto) - noticed that the temp shot up into the red so pulled over very quickly and shut the engine off. Popped the bonnet and felt the coolant pipes - they were rock solid. Waited for a while for it to cool enough to take the rad cap off and pressure was released (so I'm pretty sure the cap is working). Checked the thermostat on the roadside - it's opening and closing properly as it was open when I took it out and promptly closed as it cooled. I can feel through the thermostat opening that the impeller on the water pump is turning properly and not missing any blades. But the car is still overheating. I'd not previously touched the cooling system so there were no air locks and there were no leaks as I'd looked around the night before as I was expecting to be doing a couple of hundred miles driving today. Ended up on the back of an RAC truck from Chester. Not pleased! I can only think the head gasket has gone but there's no lumpy running, smoke or mayo! Hoping it's not a cracked head or block.... Any ideas? Quote Link to comment Share on other sites More sharing options...
Nic Posted May 9, 2011 Share Posted May 9, 2011 (edited) Headgaskets can go but it's not a common problem, it's usually something much simpler such as the rad cap, thermostat, split hose, burst radiator or knackered pump. A worn radiator cap is the most common cause of overheating, any loss in pressure and the coolant will boil at a lower temperature, the pressure will increase and you'll lose most of the coolant, the system may still be pressurised when the cap is removed. Rad caps are cheap so I'd start by fitting a new one. Fit the new radiator cap, refill coolant and bleed any air out of the system, start the car, check the radiator/hoses for leaks. With rad cap off check the coolant is circulating in the radiator when you rev the engine a little, let it idle for a while and get up to temperature, then check again for leaks. If all is well increase the revs for a few minutes and keep an eye on the temp gauge. Take it for a test drive around the block, keeping an eye on the gauge, when you get back check again for leaks and when cold check radiator for any loss of coolant. Let us know how you get on. Edited May 9, 2011 by Nic (see edit history) Quote Link to comment Share on other sites More sharing options...
straightsix Posted May 9, 2011 Author Share Posted May 9, 2011 Thanks Nic. It's going to be wednesday before I get chance to look but i'll keep the thread updated. Quote Link to comment Share on other sites More sharing options...
straightsix Posted May 16, 2011 Author Share Posted May 16, 2011 Spent all bloody week on this and missed the second pancake run so was not very happy at all!! The 'sit rep' Replaced rad cap and road tested. Overheated on road test. Made sure no air in the system by vaccuum filling system. Overheated on road test. Stripped the engine down and gave everything a damn good flush and clean. No blockages were found. Radiator in very cood condition with no leaks or blockages. Removed thermostat and tested - no fault found. Stat opened promptly at 83 degrees. Removed waterpump. All blades intact. Bearing fine. Looks very new.... Reassembled with new waterpump anyway. Refilled cooling system and road tested. Overheated on road test again! Swore. Lots. Considered buying a bike.... After a cuppa and a large farmhouse fruitcake, tried again.... Removed Thermostat and tested again. Promptly opened at 80 degrees. Flushed system again. Refilled system. Overheated on road test again. Swore lots more again. Removed thermostat - don't ask why as I just had a weird feeling about it....tested it and it wouldn't open. Tested thermostat another 8 times and found that sometimes it would open and then sometimes it wouldn't. Amazed as I've never seen a thermostat go like this - it's either opened or not. The stat is in good condition and not just sticking. So there we are. Relieved but at the same time very annoyed. Looking for a V8 now as I'm disowning this engine for all it has put me through over the past week. We haven't been on speaking terms since Saturday.... Quote Link to comment Share on other sites More sharing options...
skippyboyo1 Posted May 16, 2011 Share Posted May 16, 2011 A fantastic thread buddy....well not the situation you were in but its always good to know what issues other people have. My god an na going wrong? what is all that about! good work though finding the problem. i usualy also find that a cuppa and a cake usualy has an important part to play in problem solving. Ive noticed the v8 becoming very popular however i personaly will not be sold on the idea untill my na goes bang. Thumbs up from me Quote Link to comment Share on other sites More sharing options...
straightsix Posted May 16, 2011 Author Share Posted May 16, 2011 I'm actually going to change my stat as a service item in the future as it's a doddle to get to and a pain in the ass if it fails! I was more gutted I missed the pancakes again! Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.