Hello

I'm kind of new to this, so any help will be much appreciated. I have a 2002 Octavia 1.9 TDI 90 which has a problem with the temp dial. VAG COM reads the problem as the coolant temperature sensor, which I understand is a common problem. However, I need a hand in finding it. If you can use easy words please as I'm no mechanic ! The other thing that bothers me is that, if this is overdosing my engine with fuel, could this have led to a 0-60 in 10.5 secs . This is a few secs quicker than the literature says, and road conditions were level, low wind etc. I don't know if the car has been modified in any way. Could the replacement of this sensor slow me down?

The picture below shows where the dual temperature sender is on the 1.8T engine - ie to the right of the engine looking from the front of the car. The plastic cylinder head cover has been removed for ease of access. My thumb is resting on the U-clip which secures the sender in place. Your car's should be in a similar location. If the sender is sending the wrong information to the engine ECU, this would affect the correct running of the engine.

Thank you sir. And tell me, what is the hose running to the right of the sensor? I find these engines packed full and quite hard to tell what is what. Do you know if a change in the sensor will slow the car down?

Martin

It might well do. What sort of mpg are you presently seeing?

High 50's at the minute. A bit lower this year this year than the last. On some quite small roads too. But neither my wife or I drive the car hard. It had seemed to have a little bit of trouble with the cold starts recently, not too much though.

It'll not slow the car down much then I think; I had high 50s or low 60s out of a hired 90, despite spending 2 hours in a 1st/2nd gear crawl caused by a broken down bus on the M25!

So you think I'm losing a bit of mpg?

Maybe, but not much probably. I don't make a habit of breaking speed limits, but am a quick driver even so.

Can I ask you where the relevent part is here? I have a pic above but it is not distinct. I have a feeling it's out of sight on the passenger side of the engine, between the air filter and engine block.

I have found the part but it is a bloody nightmare to service. It is horizontal, which means the coolant runs out like billy-o. Anyone know how to plug effectively for a moment while I replace the sensor? Or should I drain the system?

Maybe jacking the car up on that side might help so the coolant stays on opposite side?

That is a possible. But I'm thinking there must be a way to plug it, even for a minute or two.

Just got to be quick but can always top up after.Won,t be that much loss.

I agree, if it is the same as the 1.8 petrol,it just unclips and can be replaced quickly. Remember to fit new o ring and leave filler cap on which will reduce water loss.

Thank you all. Completed today with a wee bit of drama! Things to note for anyone unsure is be careful of the clip. Its thin and black and if you have slippy hands, it will end up in the depths of your engine! And the car won't go anywhere! Make sure the sensor is clipped back into place properly as I thought it was but it started leaking coolant several miles from home. Hot coolant, that is, and a bit more difficult to work with than the cold stuff....Also make sure the old sealing ring is removed and the new one placed over the sensor. I found it helpful to clamp all the pipes leading to this area. I was lucky to buy an adjustible clamp set from Lidl yesterday (hurry!). There is a bit of leakage but it comes to a halt or slow trickle soon after. Anyone need a hand with this send me a message. This is for the 2002 non pd 1.9 TDI. I made all the mistakes today, so you don't have to!