Temperature warning light ??

[BigTartanJudge 0]

Hey all,

 

I have been getting an intermittent temperature warning light (I think it is anyways, red light flashs on and off next to a thermometer symbol, on bottom bit of instrument cluster, with other warning lights) on the dash over the past wee while, sometimes stays on for ten mins then off, recently has started flashing around 30 secs after car is started and stays flashing on and off constantly, until ign is switched off. Start her up again and the same light starts flashing after about 30 secs of running.

 

Is this light for overheating / temp too high, is is for the water level or what else e.g. pressure loss or some other cooling system problem ? I have just checked the coolant level prior to running her for the first time in about 8 weeks and it was bit low but only at the min mark on the header tank, so topped up and am still getting this light flashing though. I have topped it a wee bit over the past 4 months but only like twice, as she has only done about 150 miles in this time. Could it be a sensor or prob with water pump ? Also the temperature gauge seems to be working properly, i.e. rises gradually, as it should, then goes up to about 90 deg after running and stays fairly constant.

 

Am stumped with this one and don't want to run her if there is likely to be a major issue here, so any help much appreciated,

 

Cheers,

 

BigTartanJudge

[Jon_vr6 1]

Maybe a temp sensor or could be the sensor in the coolant reservoir is full of sh!t and needs cleaning! The fans coming on as normal ?? and is the waterr temp not going above 100??

[BigTartanJudge 0]

TBH, don't know if temp goes above 100 deg as she never runs for longer than about 20-30 mins at the moment and I take it the fan should just come on when running above certain temp, then stay on for a little bit after ign switched off, then swich off itself after this ?

 

How would I know if the sensor in the header tank / coolant reservoir is dirty and needs cleaning, can this be removed easily and cleaned ? Which sensor are you talking about, the blue coolant temperature sensor (CTS) - not sure where this is located or the coolant level sensor - which I thought sat in the header tank ??

 

Does the header tank only have a level sensor, a temp sensor or both ? And if so how is each one removed and cleaned ? Also, how do you test if they are dead / need replacec etc ?

 

It's a 1992 G60 if that helps any,

 

Cheers

[Jim 1]

Welcome to my hell.

 

I'd gladly like to see some good advice on just where the hell the dash warning light obtains its 'panic' signal from - I know about the coolant expansion tank but i'm lead to believe that there are other sources, but cannot get clear information on where else might be a trigger.

 

So far though Struan (if it helps) i've been advised to check that the clocks themselves are not faulty, that you have the correct mixture of coolant in the system (apparently too weak and it'll give a light) and obviously to check / change the expansion tank itself as the prongs get corroded and don't function properly after time.

 

There is nothing replaceable in the expansion tank - the prongs are molded into the bottle. You need a new expansion tank and I strongly advise steering clear of GSF ones as they're pants quality.

[Jon_vr6 1]

The temp sensor (yellow one) is on the thermostat housing mine went recently (temp just kept going up and up and then the dreaded coolant warning light came on and then realised the fans wernt coming on aswell) all sorted now!! The coolant sensor (expansion tank) i dont know much about! Your best bet is prob running it up to temperature and see if

1. The fans come on at the right time

2. It stays at a steady 98-105 and doesnt go above!

 

Bear in mind mines a VR6 so could differ!

 

Jon

[BigTartanJudge 0]

So the yellow temp sensor is the coolant temperature sensor and is on the thermostat housing.....uh where is the thermostat located and is it in the same place on G60's as it is on VR6's ?? Therefore this would mean that the sensor inside the coolant header tank is the coolant level sensor, correct or Jim, as you said is there no sensor inside the expansion tank at all?? Is there a sensor as well where the connector plugs into the expansion / header tank or is this just a connector alone ? When should the fan come on (at what temp I guess) and how long should it stay on for ?

 

Sorry for al lthe questions, just want to get this sorted and cover all possiblities.

 

So at least I should get a new expansion tank from VAG dealer and replace it (not too exp I think), old one really dirty as well so could do with being replaced anyways, and get the coolant system flushed and new G12/13 coolant put in to the correct mix to see if doing these cheaper thinngs solve the problem first ?

[Jon_vr6 1]

Yes yellow is temp sensor it should be on the right side of the engine (on vr6)

Ok the header tank one must be a level sensor i stand corrected lol

Fans come on anytime from 90 to 100 degs - 10-20 seconds about

[Jim 1]

The classic cause is definately the expansion tank bottle / sensor.. worth doing that first.

 

Think they cost about £30 tho :(

[BigTartanJudge 0]

So I take it if I unplug the plug / connector at the header tank and bridge the plug/connector with some wire to see if it stops the flashing, and if it does this will tell me that the expansion tank needs replacing, assuming coolant level is good (would tell me that collant level sensor is faulty) ?

 

If this doesn't work, I could replace the coolant temperature sensor and actual sender itself to see if this fixes the problem ?

[BigTartanJudge 0]

Anyone else got any suggestions or can confirm any of the above ?

[easypops 8]

i had a problem a wee while back....overheating....now sorted with new thermostat , thermo fan switch and water pump.

before it was fixed my light came on sometimes and all i did was top it up with water , turn it off , start again and the light stayed off ?.....i thought it was a level warning and not temp but not sure

[Bojmobile 0]

So is it checking coolant conductivity as well to ensure the correct mixture Jim?

[BigTartanJudge 0]

anyone any further ideas on this one ?

 

Cheers

[Jim 1]

So is it checking coolant conductivity as well to ensure the correct mixture Jim?

 

Indeed mate - that is what i've been told anyway!