Guest JARushby Posted October 19, 2008 Share Posted October 19, 2008 I have a problem that is now starting to mystify me. Basically the car's temp guage never used to move from half way. If I leave it ticking over it still doesnt. If I cruise around at a reasonable pace everything is fine. However if I accelerate hard or uphill the temp guage rises quite quickly to the red (or just beneath), if I ease off over th enext minute (probably less) it returns to normal. I have checked the thermostat (what a fun job that was to remove) and that works fine in a pan of boiling water. I have replaced the radiator cap. I have replaced the fan belt thinking it may be slipping on the water pump when accelerating). I have jacked the front up and ran for 5/10 mins with teh rad cap off and heater on full. I diagnosed also that teh the temp sender at the bottom of the radiator was suspect and so diconnected to keep the seconday fan on 100%. The viscous fan is not seized. On tick over I can stop the fan with a thick piece of cardboard but I would guess if I tried to stop with my hand it would sever my fingers (just a guess but probably not worth putting to the test). At the time when the temp guage starts to rise I also notice that the heater blows cold air. When temp guage drops back to half way heater seems to function ok (ie blows hot air). I am still working on the assumption of an air lock. I assumed that 5/10 mins with rad cap off and jacked up would be enough to bleed??. Please help someone, running out of ideas J Quote Link to comment Share on other sites More sharing options...
Jamesy W Posted October 19, 2008 Share Posted October 19, 2008 Is your coolant bottle empty? Quote Link to comment Share on other sites More sharing options...
Dazzi Posted October 19, 2008 Share Posted October 19, 2008 Replaced your rad cap recently? If not try it. Quote Link to comment Share on other sites More sharing options...
Guest JARushby Posted October 19, 2008 Share Posted October 19, 2008 Is your coolant bottle empty? No, coolant filled up to top. Quote Link to comment Share on other sites More sharing options...
Guest JARushby Posted October 19, 2008 Share Posted October 19, 2008 Replaced your rad cap recently? If not try it. Yep, got a new rad cap. Same problem Quote Link to comment Share on other sites More sharing options...
Jamesy W Posted October 19, 2008 Share Posted October 19, 2008 I had the exact same problems a while back. I never knew that the coolant reservoir had to have coolant in it Flushed and refilled the system and rep0laced the rad cap. Problems solved. Is there any splits in your rad hoses? Quote Link to comment Share on other sites More sharing options...
Dazzi Posted October 19, 2008 Share Posted October 19, 2008 When you say filled to the top do you mean to the max/hot mark or to the top of the cap? Quote Link to comment Share on other sites More sharing options...
SimonT Posted October 21, 2008 Share Posted October 21, 2008 I have a similar issue to this but my car only seems to try and overheat when sitting in traffic but as soon as i put the heater on the gauge goes back down! However, it doesnt always overheat in traffic and recently when i had my MOT they had the car running for a good 20 minutes and the fans cut in and temp was fine!! Am i right in saying i could have a sticking thermostat that isnt always opening when it should and just replace it?? Anybody's help would be appreciated!! Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted October 21, 2008 Share Posted October 21, 2008 I would check the water pump, sounds like its not efficient at higher RPM, IE corroded impeller, or loose even. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted October 21, 2008 Share Posted October 21, 2008 I would bite the bullet and renew the t/stat, how they behave under pressure can be very different to in a pan of water on the Aga I would also check the rad for flow, it may be blocked internally. Renewal is the only worthwhile fix in that case. Is it an N/A or a TT? Quote Link to comment Share on other sites More sharing options...
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