Monkeyfeet Posted November 11, 2016 Share Posted November 11, 2016 I'm new to the world of LR's, been Citroen for too many years, but I've been after a Disco for some time, and have just picked up a 300TDi auto, 1994. Took it out for the first time yesterday and found some issues that I'd not noticed before. I'll go one per post for the time being though : On a run of some twenty five miles or so (some cross country 60mph / some stop start, quite mixed) the only time I saw the temperature gauge just about lift off it's lower-white-line reading was when I floored it (kick down test) up a hill. The reading dropped straight down again afterwards. Getting some warm air out of the vents. Looks like it has the original viscous fan, which was spinning from start up. (whilst i was checking auto fluid) I'll check out the wiring this morning, but I'm wondering if the fan should spin straight up like that, or is it more likely just a problem with the 'stat? Many thanks. Quote Link to comment Share on other sites More sharing options...
Monkeyfeet Posted November 11, 2016 Author Share Posted November 11, 2016 Just for info. Had a chance to get under the bonnet this morning. Checked the sender wiring. Earthing the sender wire gives gauge full (hot) reading. Cleaned the brass connector off and if that makes no difference I'lll swap out the sender. Seeing 1.1K at 10C ambient incidentally. Wire and connector could do with need changing too. Engine off the fan turns easily by hand so I'm guessing thats ok. Quote Link to comment Share on other sites More sharing options...
steve_a Posted November 12, 2016 Share Posted November 12, 2016 Viscous fan will always spin, but if the engine is doing say 2000rpm then then fan, unlocked, will be doing 800 for example. Once locked up it will be one for one. TDi's run nice and cool, I removed the viscous fan off mine in the UK and had an electric for the odd time (mainly off road) that it was needed. So your gauge is probably fine, even here in Aus, the 300TDi in winter (so usually about 15 to 20 deg c ) it would take 15 mins to get some hot air out of the heater. On overrun in the Snowy mountains I actually had the engine temperature drop below warm up after a fair bit of time coming down.... Quote Link to comment Share on other sites More sharing options...
elbekko Posted November 12, 2016 Share Posted November 12, 2016 As long as there's hot air coming out of the heater, you know there's not an air lock so that's not the cause of the gauge not working. In winter it should take a good 20 minutes before it starts heating up, but it should definitely heat up eventually. You can check the fan by trying to stop it with a bit of rolled up newspaper when it's cold. If you can't stop it, it's faulty. It could also be your thermostat just isn't closing properly. Quote Link to comment Share on other sites More sharing options...
Monkeyfeet Posted November 13, 2016 Author Share Posted November 13, 2016 (edited) Hi Guys, thanks very much for the replies and advice, being a newbie here it's nice to get them! Sounds like I don't need to worry too much, in that they all run cool. Yes some warm air, and I've noticed too that the gauge points south again when going downhill (not much in the way of hills around Bedfordshire though... I plan to give a full service and check over (courtesy of Mr Haynes) and might as well get a new stat while I'm at it just in case. I'll try the newspaper trick too, thanks. Edited November 13, 2016 by Monkeyfeet spelling mistake Quote Link to comment Share on other sites More sharing options...
Boydie Posted November 14, 2016 Share Posted November 14, 2016 Does you car have air conditioning ? If it does then the two sensors located in the elbow after the thermostat are for the A/C. One turns the condenser fans on to assist cooling if the water temp gets to 105*C the second sensor turns the A/C compressor off if the temp continues to rise and gets to 110*C. My Disco (manual) never goes above 90*C and after driving up extremely steep hills on 40*C ambient dayd resorting to dropping back into second gear with 14.5 psi boost. On the downhill runs it drops back to around 80*C. If you replace the thermostat, (a good move in my opinion), a trick is to get rid of the silly little toggle thingmegig in the vent hole and drill out the vent to 1/8" or 3mm and remember to have it at the TOP of the thermostat. Remember to use the correct ratio of antifreeze coolant to water and you should have very few, ios any future problems. If your alloy thermostat housings show any signs of corrosive pitting on the jointing surfaces smear a small amount of high temperature silicone gasket sealant on them before installing the thermostat. Quote Link to comment Share on other sites More sharing options...
Sabre Posted November 15, 2016 Share Posted November 15, 2016 On 11/11/2016 at 0:20 PM, Monkeyfeet said: I'm new to the world of LR's, been Citroen for too many years, but I've been after a Disco for some time, and have just picked up a 300TDi auto, 1994. Took it out for the first time yesterday and found some issues that I'd not noticed before. I'll go one per post for the time being though : On a run of some twenty five miles or so (some cross country 60mph / some stop start, quite mixed) the only time I saw the temperature gauge just about lift off it's lower-white-line reading was when I floored it (kick down test) up a hill. The reading dropped straight down again afterwards. Getting some warm air out of the vents. Looks like it has the original viscous fan, which was spinning from start up. (whilst i was checking auto fluid) I'll check out the wiring this morning, but I'm wondering if the fan should spin straight up like that, or is it more likely just a problem with the 'stat? Many thanks. The standard 300 TDi gauge has a "dead" band built into it, to reduce short term fluctuations. And will nearly always show "normal" (half-way up the gauge) when working. I changed my temp gauge for a VDO gauge and sender unit, and the true temperatures were quite a revelation to me. The VDO always gives an early warning when temps are getting high OK, I know high temps might not be your problem, but running an engine at too low a temp is also not good. You can also consider replacing the current thermostat with one that opens a few degrees later Quote Link to comment Share on other sites More sharing options...
Boydie Posted November 15, 2016 Share Posted November 15, 2016 Much to the contrary belief but the top of the Disco radiator is just above the cylinder block, very little coolant actually passes into and out of the cylinder head. If you park your car on a flat level piece of concrete and get out a three foot long builders level and tape measure you will see that I'm right. That said if you do have a water leak and the water temperature sensor is NOT in the water, but is in air it WILL read low and will continue to do so until your engine expires. The solution to this is an invaluable piece of kit called a low water alarm. This has a probe that will operate a screeching alarm if the water level falls and the probe isn't fully immersed, mine is installed in the radiator filler plug. You can buy them at most auto stores on on EBay and they take about an hour to fit and wire up. From memory mine cost me about AUD$75.00 which is a lot cheaper than the cost of a seized engine rebuild. Quote Link to comment Share on other sites More sharing options...
Monkeyfeet Posted December 10, 2016 Author Share Posted December 10, 2016 There's some interesting points raised there. Useful info. Fitted a new 'stat yesterday - I then let it sit on the drive, checking for leaks (the new stat came with just the black rubber seal which fits round the outer edge of the stat, but no paper type gasket), After twenty mins or so the temp gauge went to halfway and stayed exactly there for the next fifty odd miles in traffic queues, motorway and mixed driving. I'm guessing either the old one was opening too early or, more likely, the old rubber seal wasn't doing very much, it was a bit twisted and stretched. Ta for the fan check trick too: The fan will stop at cold (I used an old towel but never mind) so that's definitely ok. Nice and warm motor and heater for the winter Thanks again! Quote Link to comment Share on other sites More sharing options...
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