HELP - Not overheating !!!

FatController · Post by **FatController** » 27 Mar 2005, 02:27

Hi All.
Have just bought a 1995 Xantia 1.9SX TD, with 111000 miles on it.
All appears well, apart from one nagging thing. Once I have covered about 3 miles, the orange warning light on the temperature guage lights up. The temp guage stays at about 80 degrees and doesn't appear to go any higher, but the light won't go off until the car cools down.
Where do I start looking for a cure ? The handbook for the car says this is an overheat "pre-warning" on the TD ?
Any (useful!!)help gratefully received,
thanks,
Lee.

Dave Bamber · Post by **Dave Bamber** » 27 Mar 2005, 03:13

Have you checked the water level? I know it's obvious but you never know!

FatController · Post by **FatController** » 27 Mar 2005, 18:16

err .... yes

Tried that one but it's fine, and it's not losing any water at all. One other thing, don't know much about diesels - YET ! but when I bought the car, to the front of the block, on the right hand side, there is an upright cylinder (fuel heater ? fuel filter ?) with a couple of pipes coming out of it. On the front are two electrical connections.
The plug on the RIGHT of the cylinder was not plugged in. Now it is - and the coolant lights coming on. As I say, I'm not yet familiar with these engines and can't get to anywhere to pick a manual up until Tuesday.
Can anyone confirm if this WOULD make a difference ?
Thanks
Lee

tonespeed1999 · Post by **tonespeed1999** » 27 Mar 2005, 18:21

looks like the seller unpluged the sensor to sell the car,i would buy a new sensor and then go from there, its the cheapest option,if the cooling fan cuts in ok,and car doesnt overheat, go for the sensor!

jeremy · Post by **jeremy** » 27 Mar 2005, 20:16

I had this in mind when I was looking at something on our ZX this morning - yes the black cylinder is the fuel filter/heater. there are 2 sockets in front , on the ZX the left hand (facing it) has a blue plastic fitting which is the temperature gauge pick up. The other socket has a blanking plug in it and the explanation is that on the ZX the temperature warning light is in the gauge and presumably shares the same sensor for better or worse.
Probably worth removing the sensor and seeing if its marked with a temperature and then trying to test it by heating in water and see if it operates (you will need a multimeter for this as well as a thermometer.)
Gauges are generally regarded as more reliable than lights simply because you can see if they are apparently working correctly. Nevertheless I think you are on notice of overheating problems and as you will see from this site XUD's are not very tolerant of overheating.
The cooling of diesels is exactly the same as petrol engines and I'm sure by now you've identified the various components.
I think first you have to ascretain the temperature in the pickup positions reliably - ie is the gauge right. If it is you haven't got a problem and may need a new light sensor. If you ahve a problem check the simple bits first - thermostat, radiator (crossflow so silts up from the bottom and may respond to flushing -you may be able to feel cool area.
jeremy

vanny · Post by **vanny** » 27 Mar 2005, 20:33

FYI - The blanked off port will have a BROWN connector where AIRCON is fitted, it is simply another temp sensor (they may possibly be identical) and i actually run the temp guage off this one simply because it's there and my engine is the bastard child of electrics from a BX and a Xantia

Post by **RichardW** » 29 Mar 2005, 18:17

But, with that connector unplugged, the Bitron unit (which controls the fans, aircon and overtemp warning lights) should bring both cooling fans on at full speed (default failure mode), also the red STOP lamp and red overtemp light. Something is not right, and you need to get to the bottom of it before you cook the headgasket in traffic on the first warm day! Does the air con work, do both the fans come on at half speed when the aircon is switched on, if you leave the engine idling, do the fans come on when the gauge gets to approx 92 - 95 °C (if you try this don't let it get above about 100 - if the fans have not come on, switch off and drink tea while you think about it).

ActivaV6uk · Post by **ActivaV6uk** » 29 Mar 2005, 18:47

I may have one of these sensors you can have if you need one.
Andy

jeremy · Post by **jeremy** » 30 Mar 2005, 01:16

Richard - is the setup on a 95 car or was this later?
just something at the back of my mind concerning the use of the bitron and age of vehicle. It may have been that it was used anyway rather than exclusively on air con cars.
jeremy

Post by **RichardW** » 30 Mar 2005, 13:48

I think Bitron for all Air-con cars, and Bitron for all cars 97 on ( or some date like that) - mind you most had air con by then anyway.

FatController · Post by **FatController** » 31 Mar 2005, 04:00

Hi chaps.
Took a bit to get back - sorry.
OK - the car DOESN'T have aircon, just normal heater. When I unplug the cable from the sensor to the right (single cable) the red lamp stays ON.
Also - have driven quite a way - the temp guage doesn't go over 85, though not yet got to trying to find out if the fans come on when I let it idle.
Cheers,
Lee.

Post by **RichardW** » 31 Mar 2005, 13:49

Ah, no aircon and early car makes life simpler. Must be the sensor at fault. Measure its resistance cold, and then again hot - it should be markedly different. If not, change it. From your gauge it sounds like the cooling system is working OK - you really have to work the engine hard to get the temp above 80 this sort of weather.

FatController · Post by **FatController** » 31 Mar 2005, 22:44

Thanks Richard.
I'll give that a try at the weekend, hopefully you'll be right and it'll just be a sensor !!!!!
Lets hope so - it's now off to sunny Spain next week !
Regards,
Lee.

Dohnut · Post by **Dohnut** » 01 Apr 2005, 02:26

Have a similar problem, Xantia Sx 2.0 Hdi W reg.
Both the red stop light, and the red light on the temp gauge, flash on and off while driving. Have checked the water level put a small amount in checked again a day later header tank was still full, so dont think that was the problem.
At first I thought it might be overheating but temperature gauge stays at 85c, did hear the fans start up every now and then and the lights went out (may be a red herring), even then the temp gauge stayed at 85.
Heres the funny bit, Ac control is in auto mode, Hot and cold control can be any where, Vent control in on demist and lights flash on and off, move the lever to side vents or down to feet vents and lights go out, move the lever back to the demister and count 5 or 6 seconds and both lights flash on again. Also put the air con on and the lights seem to come on regardless of where the heater controls are placed.
Looks like a sensor might be playing up but which one and where is it.
Any ideas before the good weather comes along (Ha ha) and I have to do without the air con, just to stop the lights flashing before my eyes.

Post by **RichardW** » 01 Apr 2005, 14:03

This probably means that one of the cooling fans is stuffed. When the aircon comes on both cooling fans should start. If they don't, the Bitron detects a fault, and starts the dash board disco. On later cars, A/C comes on automatically on demist, hence the disco then as well. Switch on the A/C and see if both fans are running. There are several posts on here about removing the awkward cooling fans. My mate was having similar trouble with his 306, but this was fixed by removing one of the cooling fan relays and cleaning it up a bit.