Temp warning question

[yeleek]

Hi,

 

Driving my 63 plate DSG diesel Octavia this afternoon.  Doing 40 mpg on a country lane, internal temperature was set to 16 and auto, but AC was not on.  External temperature reading 12c. 

 

No previous problems with car, I had just parked with the front of the car by some thick bushes, on way home high temperature warning message comes on dash, pull over straight away, can see the car temperature raising from 120 to 130 in a couple of seconds, turn car off.  Open bonnet looking for leaks in rad (none found), look for any leaves which could have blown in, none found.  Leave it 5 mins, turn car back on, temperature reads as 90 as per normal.

 

Drive a mile up the road and see the temperature again rise from 90 to 110 very quickly, maybe 5 seconds.  Turn it all off, lift bonnet checking for more leaves (none found).  Turn car on and set internal fan to high temperature and its blows within the cabin.  Rev the car, temperature stays at 90.  Drive home with front windows open and fan on high temperature, temp remains at 90.  Turn fan off, driving home and temperature remains at 90.  Turn the temperature of the fan to a more reasonable 18, again temperature remains at 90 and stays that way for the next 5 miles home (including when I put air con on).

 

I find it hard to believe the temperature rose and fell so quickly (seconds), so what am I looking at here?  Did some leaves get stuck?  Is it a possible fault with the temperature monitoring?  Any previous experience or thoughts as to what to do next would be gratefully received.

 

Thanks

[Frenchtone]

engine thermostat stuck or knacked?

[yeleek]

Is that because the temperature is unlikely to have actually changed so erratically so quickly, and then appear fine?  I'm obviously happy to take it to Skoda to get it fixed.  Its just is it a cannot drive it at all problem or drop it into Skoda mid week type of problem?

 

THanks

[spinifex]

I would suggest this is NOT normal behaviour, and needs to be checked ASAP.

What you've done to try to identify/rectify the problem, seems perfect... and reminiscent of old-school 1970's cars.  Turn heater on inside the cabin, to minimise engine overheating due to waterpump or thermostat failure.

These cars are prone to waterpump failure though, from my understanding.  As a completely unqualified opinion, it sounds to me from your description that it's probably thermostat failure due to no visible leaks - if it was waterpump, it would have an obvious leak surely?

 

Get it to service centre as soon as possible to get checked.  I personally wouldn't try driving it using your cabin-heater bypass method for too many days, in case it's a more serious internal problem and it causes more damage.

[themanwithnoaim]

Water pump, there is a whole thread on here about it, usually VRS TDI's.

 

Such has been the failure level that Skoda have been discounting out of warranty cars, 50% off is common but I have heard of 70% being given as well.

 

BTW, get the cam belt replaced at the same time, its like 1/2 an hours extra labour so, a no brainer 

[yeleek]

Thanks for the replies.   As the problem suddenly arrived and disappeared yesterday, I wanted to test it again today.

 

Just took it for an 1hr 10 min journey (mainly town centre) covering 23 miles.  Engine temp took about 1.5 miles to get up to 90 and stayed there, oil temp (once hot) varied from 90-101.  Tried air con on (hot and cold), fan without air con (hot and cold), also tried with automatic stop on and off.

 

Engine temperatures didn't vary.

 

I'm gonna book it into Skoda for a service anyway and ask them to check it, but am confused as to whats going on.  Is it possible its a loose connection?  I was rear ended a few weeks back (all sorted now on their insurance), just wonder if that impact could have caused a connection problem?

 

Cheers

 

 

 

[Sec8200]

water pump is main suspect. Read the relevant threads, no leaks.

[themanwithnoaim]

Apparently, there is a sleeve that opens for the water pump to operate, when it fails temps risr & pumps fail.

[Gabbo]

+1 for water pump.

Its a common fault on the TDi from reading the forum.

 

When the engine is warming up, the coolant circulates around a small circuit to improve the warmup.

When the temperature reaches a threshold the water pump kicks in to mix the hot coolant with the cooler water in the tank & rest of the circuit.

Theres a plastic sleave on the old pumps which can prevent it from mixing in the cooler water, hence the sharp rise in temperature.

Once the pump manages  to start, the temperature drops quickly back to normal.

 

I would take it to the dealer asap.

They should know exactly what it is from your description.