Good evening all.

I suspect that having trawled the forum I know the answer to this, but just as a sanity check.....

Driving my normally reliable, bog-standard 2003 Octy 1 VRS at 7am this morning, just 3 miles from home, when the coolant light and buzzer activated.

Looked that the guage and the temp was in the red at 130c. Performance a bit sluggish at this point.

Pulled over, switched off, opened bonnet. No smoke, no leaks, no geysers of anti-freeze. Top hose was hot to the touch but not 130c hot. The water level in the coolant ball was well above the seam.

Checked the gauge again and it's back to the normal 90c, and the light is off.

Waited 5 mins, closed bonnet, drove off. The gauge climbed back to 130c within a mile. Repeat the above.

I called out the RAC who diagnosed a faulty temperature sender, apparently a common VAG failing. The RAC man based this on:

1. that the engine didnt feel too hot to the touch even with the gauge well above 100c

2. that even having sat for 15 mins the gauge still showed 90c

With the RAC van in convoy, I drove to the local village garage, who ordered a new sender, and fitted it while I took the train to work. The garage also plugged in an OBD2 code reader but the ECU hadn't recorded a fault.

I picked the car up this evening and it's no better.

Is the water pump at fault?

Could it be anything else?

If it is the pump, where can I get a metal impeller pump, as recommended several times on the forum. I'm just outside Nottingham so have both a GSF and Euro Car Parts within range.

The car has 125k miles up. The cambelt was changed at 90k but not the water pump.

Thanks in advance for any advice.

Best regards...........Jonathan

Sound like water pump to me, faulty temp sensors normally read less not more. You should always replace water pump when belt is changed.

:iagree:

My first thought would have been sensor too, since there was no sign of overheating other than the guage, but it looks rather like the water pump now.

You should be able to get a metal impellor unit from one of GSF and ECP, but phone ahead, and don't forget that you might as well replace the cambelt again when you're in there anyway!

I had a similar problem a few years back. I was told that the thermostat stuck open and water pump impeller disintegrated - thankfully fixed under warranty.

I'd agree with the above. Definately sounds like a water pump if its never been changed and the car is on 125k.

The question is, why on earth hadnt it been changed at the cambelt service?!

The question is, why on earth hadnt it been changed at the cambelt service?!

Good point ! :confused:

Have you had it since new ?

Water pump impeller has either disintegrated or separated from the shaft.

The question is, why on earth hadnt it been changed at the cambelt service?!

It isn't always necessary depending on the make of car TBH. As it's a known issue on some VW based cars people who are aware of it will probably change it as a matter of course, but some owners or the garage doing the work won't change it unless its specifically requested.

Personally, I would always change it when having the cambelt changed, and if I'm having that done, then I may as well have the coolant changed and the thermostat replaced at the same time. As was done last month on mine by Awesome.

I know the failure modes seem to be more common on the hotter-running petrol models, particularly the vRS, and seem to be more related to engine hot run hours than to mileage.

Thanks for all your help.

I bought the car 18 months ago with about 90k miles on it, and the cambelt had been changed by the previous owner at 88k.

I rang the garage that swapped the belt, but they confirmed that the cambelt kit does not contain a water pump, just a belt and tensioner.

Clearly as previous owner was moving the car on, he didn't strech to a new water pump.

Best regards..........Jonathan

waterpump! try putting heater on full in hot position to see if this brings it down a bit,mine did! no pump means it does not pump to radiator so block gets and stays hot

thanks ,john

I dont think id contemplate driving it at all unless its a very short distance to a garage.

I suspect that having trawled the forum I know the answer to this

Hope you found this one: http://www.briskoda.net/forums/octavia-i/vrs-sudden-temp-rise/86450/

I'd recommend metal impeller pump, new thermostat to be safe, and check temp sensor is a green top one while you're there (the latter is easy DIY, so don't pay anyone to do it unless you're really worried).

Thanks to all the help from those who replied.

The car is back to full health.

The problem was indeed a split water pump impeller. Luckily it had split in two 180 degree segments and nothing had vanished into the waterjacket.

It's now replaced with a FEBI metal impeller type. The garage insisted on this type before I even suggested not using the genuine VAG part. The cambelt was also replaced while all the bits were off.

Best regards.........Jonathan

Sorted!!!!