VR6 South 0 Posted November 13, 2003 Seems like every time I come to a stand still for more than a few seconds or parked up after driving a few miles my radiator fans kick in, the temp gauge reads 110 deg when this happens and the temp soon drops. There's loads of water and no sign of any leaks. Any ideas? Guess this will take priority over the duff sunroof :( Quote Share this post Link to post Share on other sites
JT 0 Posted November 13, 2003 could it just be a dirty temp sensor telling you it's over heating :!: Quote Share this post Link to post Share on other sites
VR6 South 0 Posted November 13, 2003 Where is it located and is it something that can be cleaned or easily replaced? Cheers Quote Share this post Link to post Share on other sites
Vdub bug 0 Posted November 13, 2003 the temp switch is on the right side of the engine in the cooling flange where all the cooling hoses join if it is faulty then you need a new one it has a 4 pin plug attached to it, If it is not your temp switch then it cound be your secondary water pump not good. :? Quote Share this post Link to post Share on other sites
dr_mat 0 Posted November 13, 2003 If you stand still the temp will climb. The VR produces a lot of heat, and needs the fan running even just at tickover almost constantly to keep the temps down. If I'm standing still I rarely see the needle move off 100 degrees at *all*. In extreme conditions I've seen it climb slightly above that, but not by much. I ought to know the temp limits of the car now - I sat for no less than three hours to move no more than 5 miles in a queue on the M1 north about two months ago. Engine running 95% of the time, but only at tickover... Majorly irritating, I can tell you!! Quote Share this post Link to post Share on other sites
VR6 South 0 Posted November 14, 2003 Looks like the aux water pump 80 quid :( 10/10 Vdub bug 8) Getting it fitted tonight though :) Thanks to all for the advice. Quote Share this post Link to post Share on other sites
dr_mat 0 Posted November 14, 2003 The aux water pump shouldn't make that much difference when the engine is running. The main pump should be plenty (particularly at tickover). Hope this helps, but you might find there's another reason aswell! Quote Share this post Link to post Share on other sites
PhatVR6 0 Posted November 14, 2003 The first speed of the fan with be goosed, common fault. Quote Share this post Link to post Share on other sites
VR6 South 0 Posted November 14, 2003 Thanks. I have had the fan checked and it runs at all speeds. Forgot to say that the temp sensor is being replaced. The aux water pump is leaking as well so needs changing Quote Share this post Link to post Share on other sites
PhatVR6 0 Posted November 14, 2003 It shouldn't get up to 110 if the fans come on at 90 like they're meant to. Do they? Quote Share this post Link to post Share on other sites
VR6 South 0 Posted November 14, 2003 Pump now replaced, turned out to be seized as well as leaking. Also replaced rad fan switch. Still got the problem though :? Help Quote Share this post Link to post Share on other sites
Borat 0 Posted November 14, 2003 I am no expert with engines but this was happening with mine (2.0, 16V) and it came down to a shagged drive belt. Once changed it has been fine. Have you checked the coolant recently?? just a thought :D Quote Share this post Link to post Share on other sites
VR6 South 0 Posted November 14, 2003 Just been fully topped up with G11 coolant, and purged of air after changing the switch :? Belts OK as well. The mystery continues :) Quote Share this post Link to post Share on other sites
Scott 0 Posted November 14, 2003 It shouldn't get up to 110 if the fans come on at 90 like they're meant to. Do they? Fans do not come on at 90 degrees.... the first one comes on at circa 100deg and the second one at 110deg - this is why when you do hit 110deg it comes down pretty fast. From what you say I dont think you have a problem mine hits 110deg when stuck in traffic and usually sits at 95-100deg round town and 90deg on motorway... had my VR 18 months now and its been fine. As long as the light does come on and flash/beep then I really wouldnt worry about it. Scott Quote Share this post Link to post Share on other sites
CorradoVR6-Turbo 0 Posted November 14, 2003 I would change the water pump to make sure the flow of water is good as the blades can rot away with no antifreeze and the blades that are attached to the shaft of the pump can spin loose( ive seen this many times) as for the secondary water pump it mainly comes in when the engine is off as the pump keeps the water flowing until the fan gets the water temp down... But my money is on water pump having no blades left.. Quote Share this post Link to post Share on other sites
vr6storm 0 Posted November 14, 2003 i would also take the water-temp guage's reading with a pinch of salt too...........my water temp guage reads upto 110 deg if idling in traffic quite a lot.....had me s****** myself for ages until i had ess_three hook up his VAG-COM and had the real temp values shown*........when my water guage was reading 110 deg it was actually only 97deg by VAG-COM when the fans cut in it took it down to 92 deg on VAG-COM which was just under 100 on the water guage......if you can get someone with VAG-COM to hook it up to your car you'll be able to see how accurate your water temp guage is..............*providing of course VAG-COM is accurate :wink: Quote Share this post Link to post Share on other sites
dr_mat 0 Posted November 15, 2003 VAG COM can only be as accurate as the temperature sensors... Unless it does some clever calibration thing.. But I can't see how it *can*.. Quote Share this post Link to post Share on other sites
vr6storm 0 Posted November 15, 2003 VAG COM can only be as accurate as the temperature sensors... Unless it does some clever calibration thing.. But I can't see how it *can*.. understood........but the water temp guage can also be giving a "false" reading.....eg when its 90 deg the guage could be reading nearer 100 deg if you know what i mean :wink: Quote Share this post Link to post Share on other sites
Ess Three 0 Posted November 16, 2003 VAG COM can only be as accurate as the temperature sensors... Unless it does some clever calibration thing.. But I can't see how it *can*.. Yeah, and the temperature sensors either work or they don't. Normal temperature sensors for automotive use are simple RTDs, and as long as they are used in their linear range they are accurate and fit and forget...they just don't go out of spec...you either read the correct resistance accross them for the applied temperature, or they fail (normally open circuit, giving a very high - but false - reading) If RTDs are perfectly acceptable for use in critical control applications in such industries as the North Sea Oil / Gas Industry, they are fine for use in a Corrado. With regard to calibration...it's simple physics.... Take a PT100 platinum based RTD...0 degrees = 100 ohms. 100 degrees = 135.8 ohms. And everything in between is linear...so if the ECU sends a 5v dc signal to the sensor, and the resistance is affected by the temperature in question, the resultant voltage measured on the return wire to the ECU is linear, and less than 5v - depending upon how much is dropped accross the resistance of the temperature sensor....you get the idea! The VAG Com doesn't need to do any calibration as the source voltage from the ECU does not change, and since all sensors (all sensors for that particular application...ie, that part number) are selected to ensure they are in their linear range, there is no calibration to be done. All the VAG com does is look at the range of the sensor - the span if you like...say 0 degrees to 150 degrees, look for the applied signal voltage and measure the voltage dropped...from there it's simple physics. Now, RTD type sensors do go wrong occasionally...but it's rare...normally if they work they are accurate...if they are not accurate it's corrosion on the connections that is the cmost ommon cause. Quote Share this post Link to post Share on other sites
Ess Three 0 Posted November 16, 2003 Just to back up what Roddy said, the temperature gauge is a joke! The markings on the gauge have very little to do with the actual temperature...notice that VW dropped the graduated temp gauge after the Corrado...all current VAG gauges have 3 basic positions: Needle hard left = cold. Needle in the middle - anywhere from just off hard left to just before hard right = OK Needle hard right = hot! If you're fans are working, and the needle isn't hard right and the warning lights are not on...I'd assume all is well. Just to be sure, see if someone with a VAG Com will log it for you...or get VG to check it with thier diagnoisic gear. Quote Share this post Link to post Share on other sites
Kevin Bacon 5 Posted November 19, 2003 I would change the water pump to make sure the flow of water is good as the blades can rot away with no antifreeze and the blades that are attached to the shaft of the pump can spin loose( ive seen this many times) as for the secondary water pump it mainly comes in when the engine is off as the pump keeps the water flowing until the fan gets the water temp down... But my money is on water pump having no blades left.. Yeah the VR's main pump has a plastic impeller, but unlike BMWs, they rarely spin freely on the spindle when the pulley is stationary. I pulled mine out at 80K because it's internal seal had blown, but the impeller was mint. Responding to the aux pump topic, it comes on at 100 degrees (engine on or off) and during the cool-down period when the engine is off. It's basically an assistant because it runs a lot faster than the main pump does at idle. Due to the silly amount of traffic in recent years, a lot of VR owners are finding the aux pumps going south through heavy use, sitting in traffic. Vr6south, are you sure you haven't got an air lock? Mine now sits dead centre of the guage (100 I think) all day long, but when I had an airlock, it would also sit at 110. Kev Quote Share this post Link to post Share on other sites
