robert_gray Posted June 10, 2007 Share Posted June 10, 2007 Hi, The last couple of days of driving i have noticed that after i have done around 20-30 miles the temp gauge has spiked up to about 4/5 of the gauge reading and then settled back down to half way. Has anybody else had this? I have a few thoughs on what it may be but i might have missed a few (not really that engine minded). It happens anytime whether i have been driving hard or just when i have pootled along. Quote Link to comment Share on other sites More sharing options...
toyotasuprauk Posted June 10, 2007 Share Posted June 10, 2007 When the car isnt too hot but still warm have you checked the radiator by hand to feel for cold spots. Quote Link to comment Share on other sites More sharing options...
s3upra Posted June 10, 2007 Share Posted June 10, 2007 Does it coincide with your a/c being on? Quote Link to comment Share on other sites More sharing options...
TrickTT Posted June 11, 2007 Share Posted June 11, 2007 Sticky thermostat. I'd get it changed asap. Quote Link to comment Share on other sites More sharing options...
tooquicktostop Posted June 11, 2007 Share Posted June 11, 2007 Sticky thermostat. I'd get it changed asap. As above sticky thermo, it happened to me for a few weeks then it stuck on the A13 in traffic and the car overheated, I would get it changed asap Quote Link to comment Share on other sites More sharing options...
robert_gray Posted June 11, 2007 Author Share Posted June 11, 2007 Cheers i think i'll do that. In reply it doesnt matter if the air-con is on or not Quote Link to comment Share on other sites More sharing options...
Kiunno Posted June 11, 2007 Share Posted June 11, 2007 I had a similar problem and bought a thermostat as well as coolant,got a mechanic to tackle it,the temp reading was all over the place,quickly coming down and creeping back up very close to the red,anyway the mech',flushed the system and put in the new coolant,said I was initially about 1L short,even though the top up tank was showing normal,problem solved without the need to change the thermostat,I'd try just topping up/changing coolant first:) Quote Link to comment Share on other sites More sharing options...
robert_gray Posted June 11, 2007 Author Share Posted June 11, 2007 Cheers, Already got the thermostat on order now so i think that i will change it anyway. Might aswell do it now, dont know how long these things last but i hasnt been changed yet i dont think so it may be getting close to its end anyway. Coolants on its way too, gonna try to change it myself next week as i have 4 day of work, Wahoo. Quote Link to comment Share on other sites More sharing options...
s3upra Posted June 11, 2007 Share Posted June 11, 2007 The reason i asked about the A/C was because i had similar symptoms with my last car(MK3-turned out to be a Head gasket:( ) However its fairly unlikely on a mk4,as you have the thermostat,change that,flush the radiator,check all the hoses,change the coolant,then keep an eye on temp gauge for a few days. Quote Link to comment Share on other sites More sharing options...
Rob Dublin Posted January 4, 2010 Share Posted January 4, 2010 Having a similar probelm of late, but noticed that the heater blows cold when the temp needle goes north of mid way, blows nice and hot when it settles down. Is it just the thermostat or have I bigger problems like HGF? Quote Link to comment Share on other sites More sharing options...
pistonbroke Posted January 4, 2010 Share Posted January 4, 2010 Having a similar probelm of late, but noticed that the heater blows cold when the temp needle goes north of mid way, blows nice and hot when it settles down. Is it just the thermostat or have I bigger problems like HGF? Still sounds like the stat. The thermostat holds the water in the engine until it gets to temperature, then it releases it to the rad where it gets cooled to be circulated back into the engine. If the stat is stuck, it doesn't release the hot water from the engine so your heater matrix is full of cold water. Once the stat opens, it allows the hot water out of the engine, into the rad and your heater matrix, hence why it blows hot air when you see your engine temp go down. HTH. Quote Link to comment Share on other sites More sharing options...
Rob Dublin Posted January 4, 2010 Share Posted January 4, 2010 (edited) Still sounds like the stat. The thermostat holds the water in the engine until it gets to temperature, then it releases it to the rad where it gets cooled to be circulated back into the engine. If the stat is stuck, it doesn't release the hot water from the engine so your heater matrix is full of cold water. Once the stat opens, it allows the hot water out of the engine, into the rad and your heater matrix, hence why it blows hot air when you see your engine temp go down. HTH. Cheers for that Fella... breathing a quiet sigh of relief! No gunk on the oil filler cap so was hoping I'd gotten away with it. Edited January 4, 2010 by Rob Dublin sp. (see edit history) Quote Link to comment Share on other sites More sharing options...
RobUK Posted January 4, 2010 Share Posted January 4, 2010 I had the same problem... Took it to my local mech and asimple top up sorted the problem... Oops Quote Link to comment Share on other sites More sharing options...
Rob Dublin Posted January 4, 2010 Share Posted January 4, 2010 So is the tempature needle accurate when the stat sticks? ie does engine temp drop that quickly once water is eventually released (1-2 seconds from top to middle) Is the temp taken from the same position as the stat? Quote Link to comment Share on other sites More sharing options...
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