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Coolant temperature / low level warning light

Posted: 04 Aug 2014, 15:59
by ColG
Looking for some advise, I will explain the problem as best I can.

When setting off from cold all as should be with the coolant temperature and no warning light flashing. If I stop and restart again after a short period (filling up with petrol or coffee break) then the warning light flashes immediately and continues to flash. The temperature guage is bang on the middle and the coolant level in the reservoir is at the maximum so I cannot work out the problem.....any ideas?

One thing I haven't checked (and can't until the weekend) is the expansion tank level. Am I right in thinking this should be brimmed? If it is low could this be the cause of the warning light?

Re: Coolant temperature / low level warning light

Posted: 04 Aug 2014, 16:02
by tonytech
The warning light indicates low coolant in the tank inside the engine compartment NOT the tank behind the numberplate flap.

Re: Coolant temperature / low level warning light

Posted: 04 Aug 2014, 17:13
by ColG
Thank you Tony.

Re: Coolant temperature / low level warning light

Posted: 04 Aug 2014, 17:34
by CovKid
Sometimes the prongs on that sensor need a good clean, particularly if cooling system has been taken for granted. You can't get to them without removing sensor obviously.

Re: Coolant temperature / low level warning light

Posted: 04 Aug 2014, 19:58
by ColG
CovKid wrote:Sometimes the prongs on that sensor need a good clean, particularly if cooling system has been taken for granted. You can't get to them without removing sensor obviously.


Thank you :ok

Re: Coolant temperature / low level warning light

Posted: 04 Aug 2014, 20:59
by Roydini
The red flashing warning light should come on briefly after turning on the ignition. If working correctly it should flash when coolant level in the Header tank (the one inside the engine bay, NOT the one behind the registration flap) is low, OR if the temperature of the coolant is too high.

If the light is flashing after the engine has been switched off for a while then it would be extremely unlikely that it is warning of overheating so my money would be on either low coolant or most likely an electrical/instrumentation fault somewhere.

With the engine stone cold, remove the coolant level sensor from the top of the Header tank (inside engine bay) and check that coolant level is as full as it can go. Inspect the o-ring whilst you're at it and replace if necessary (you can get them from Brickwerks). As Covkid says, give the two prongs a good clean and re-fit - this is the most likely culprit.

Now check the level in the top-up tank (the one behind the flap) and make sure it is between the two lines.

Go for a drive and monitor the gauge/red light. Give the engine a few minutes to cool down a bit and check the levels again in both tanks. If it looks like you have 'lost' some coolant then you may have a leak so it is worth checking the full length of the cooing system, front to back as sometimes any leaking coolant can evaporate before it really starts dripping onto the ground.

Let us know how you get on. :)

Re: Coolant temperature / low level warning light

Posted: 04 Aug 2014, 20:59
by Roydini
The red flashing warning light should come on briefly after turning on the ignition. If working correctly it should flash when coolant level in the Header tank (the one inside the engine bay, NOT the one behind the registration flap) is low, OR if the temperature of the coolant is too high.

If the light is flashing after the engine has been switched off for a while then it would be extremely unlikely that it is warning of overheating so my money would be on either low coolant or most likely an electrical/instrumentation fault somewhere.

With the engine stone cold, remove the coolant level sensor from the top of the Header tank (inside engine bay) and check that coolant level is as full as it can go. Inspect the o-ring whilst you're at it and replace if necessary (you can get them from Brickwerks). As Covkid says, give the two prongs a good clean and re-fit - this is the most likely culprit.

Now check the level in the top-up tank (the one behind the flap) and make sure it is between the two lines.

Go for a drive and monitor the gauge/red light. Give the engine a few minutes to cool down a bit and check the levels again in both tanks. If it looks like you have 'lost' some coolant then you may have a leak so it is worth checking the full length of the cooing system, front to back as sometimes any leaking coolant can evaporate before it really starts dripping onto the ground.

Let us know how you get on. :)