Water Temperature Guage

[stu_cole]

Hello Forum

I have a problem with my Auris (T-Spirit - D-4D - 08)

The water temperature guage reads normal - the accelerates to max and then starts dropping again to normal - this cycle is happening every 3 - 5 minutes

Is it a fan / thermostat / electrical sensor or something else

(The coolant was a bit low - this has been topped up (1 ltr) but there isn't any sign of water leakage)

Some general guidance would be appreciated

[Mooly]

Just some thoughts on trying to think it through.

Assume the gauge is correct for a moment. If it really is overheating then the fan should come on. Does it ? When the gauge returns to normal the fan should go off. Does it ? Possible causes... water pump impellor slipping, faulty thermostat.

Could the gauge or sensor be faulty ? If it very quickly climbs and falls then that suggests a problem with the gauge/sensor. There is to much "thermal inertia" for the engine to suddenly rise and fall in temperature. It takes a finite time.

If the engine is overheating then the thermostat should be wide open and the radiator hot at top and bottom.

[stu_cole]

Thanks for the reply

I topped the coolant up before driving home from work (45 minutes) and the temperature remained bang in the middle..... so that is good news......HOWEVER...... i've never owned a vehicle before that has lost coolant...... i'll continue to monitor and see if the levels start to drop if they do I'm guessing it's either a leaky water pump or the head gasket as everything else looks dry

If it is the Head Gasket are there any tell tale signs like the oil going 'milky' and white smoke (like a petrol car)

Again..... any guidance / general information would be appreciated

[stu_cole]

Another development ...... just been out to the car and the levels are low again.......there's no sign of milky oil...... no signs of leakage that I can see

[Mooly]

I wonder if that could be the head gasket issue, I know many have had problems. I suspect it could be from what you say. If you search this forum there are many posts on that particular issue... might be worth asking if your symptoms "fit".

[stu_cole]

Been to see Mr T and the mechanics have had a quick look and confirmed a failed head gasket. The giveaway was the blackish / grey carbon deposits in the expansion tank.

It is going in on Thursday for the official diagnosis and then the claim will be put to Toyota Customer Services.

If anyone has been through an AD Engine Claim for a Head Gasket could you let me know how painful or pain free the process was

[Mooly]

Hopefully it should all get sorted smoothly and painlessly.

[stu_cole]

Car was taken to Mr T this morning - Confirmed again that it was the Head Gasket....... and the Brake Pads need doing and front tyres are getting low

Service contacted Toyota and confirmed that the repair would be covered by the 'Technical Bulletin / Warranty'

I was already aware of this 'Warranty' 18 months ago when I purchased the Auris, this is why I insisted on a fully documented service history and used genuine Toyota parts with the services at the independent garage just in case

When Toyota approved the repair I authorised the replacement of the pads...... I know I can get them done cheaper elsewhere but I've just dodged the head gasket bullet so it's a small price to pay

My local Mr T is keeping the Auris until repaired so i'm driving around in an Aygo........must remember.......DO NOT FILL WITH DIESEL

I have attached the Warranty Document just in case someone else needs it

[stu_cole]

For additional information...........Whilst I was waiting to take it to Mr T I kept the coolant topped up to the maximum - with it topped it ran an normal temperature. There was no mixing of the coolant with the oil but a fair amount was being expelled through the expansion tank

Also the drivers side of the car was dirtier than the passengers side due to the coolant leak and the tyres had white residue marks (like salt)

Over the last 5 days I have used approximately 750ml of coolant each day - this is for approximately 70 miles each day, and about 1.5 hours of driving split Motorway (70%) - A Roads (20%) - Country Roads / B Roads (10%)

[Parts-King]

That is a very old warranty document and not relevent now, it is over 2 years old

I should also point out that it should not be posted up on a open forum as it is an internal document, just saying ;)

Kingo

[stu_cole]

On the advice of Kingo the document as been removed due to it's age and forum guidelines

Feel free to search the forum for a more up to date version

[stu_cole]

[stu_cole]

Just got the car back from Mr T - they had for 6 days which I don't think is too bad seeing they let me have a courtesy car for the whole 6 days

They also changed the front pads and disks for £225 which I felt justified on paying especially because i've got a free engine and had the courtesy car for the whole period

Does anyone have any advice for 'running the engine in' other than the advice from Mr T (run at a max of 2 - 2500 rpm for the first 600 Miles)

Thanks again to all the 'forumineers'

[stu_cole]

Been running the car for a week with no issues - just looked at this weeks fuel usage and i've averaged 51 to the gallon - where normally it's 43

I do have a question....... Should've Toyota issued a new service book for the new engine?

[FROSTYBALLS]

The service book is an outline of the service history of the car - no real detail apart from showing when services have occurred. So the existing service book should continue.