Took her in for MOT this morning , that passed no worries.

I asked for a tweak of the REVO map whilst in, they were checking this out and when they came back advised that the temp was was very high up past 115 degrees. Now my car has never run above 90(midway) even in hot weather. They explained that the fans were not kicking in which, ok i understand would help to cool, but the fact the car is getting that hot in the first place is worrying as it did not before i bought it in.(never heard fans kicking in for a while come to think of it)

I started to drive home and it went from 90 to 120 in less that 10 seconds so what the hell is going on i don't know. then the red temp light and audible alarm came on so i drove it straight back.

Worried that maybe head gasket has gone??

I did hear them giving it stick when checking map but i guess they need to do that so in a dilemma. I know i need to find out what it really is but the feeling is i am going end up coughing up to fix.

sounds very dodgy that it was fine before their "tweek". Aren't the fans notorious on these for failing?

Rad switch in the rad maybe? Does that not tell the ecu when the fan's need to come on? Maybe i am talking crap.

Are you running a metal waterpump? If the plastic impellors failing (they apparently break off the shaft), it could perhaps cause this...

Rad switch could perhaps be cause too, or dodgy temp sensor. Hope you get it fixed soon...

I'd suspect the engine temp sensor if the reported temp is climbing by 30Cdeg in 10s. 4200J/Kg-k * 5kg * 30 deg gives 630_000J in 10s to achieve that, or 63kw of energy per second just to heat the coolant. You'd need roughly the same again to heat the block and oil, before convection etc losses.

It could also mean a failed water pump, but that would have other symptoms; I'd expect to hear thermal stressing, and probably see steam through the overflow.

you have an engine capable of producing 132kW at the flywheel - with a 30% efficiency at best petrol engine that equate to a heating effect of around 300kW for an engine on song!!!!

(btw ignore all this if it occurs at idle!)

sounds very dodgy that it was fine before their "tweek". Aren't the fans notorious on these for failing?

It does sound dodgy, I think the fans are notorious for failing and i think my fans have not been working efficiently or not at all for some time, but as the temp has been fine up to today i am a bit lost.

Are you running a metal waterpump? If the plastic impellers failing (they apparently break off the shaft), it could perhaps cause this...

Rad switch could perhaps be cause too, or dodgy temp sensor. Hope you get it fixed soon...

I am running the std plastic water pump that was replaced less than 10000 Miles ago along with the cam belt, so think i can rule that out unless i have had a catastrophic failure.

I'd suspect the engine temp sensor if the reported temp is climbing by 30Cdeg in 10s. 4200J/Kg-k * 5kg * 30 deg gives 630_000J in 10s to achieve that, or 63kw of energy per second just to heat the coolant. You'd need roughly the same again to heat the block and oil, before convection etc losses.

It could also mean a failed water pump, but that would have other symptoms; I'd expect to hear thermal stressing, and probably see steam through the overflow.

They guys did think it was the temp sensor but ruled that out initially after some verification testing(don't ask me what, and if it is a complete rule out as yet)

you have an engine capable of producing 132kW at the flywheel - with a 30% efficiency at best petrol engine that equate to a heating effect of around 300kW for an engine on song!!!!

(btw ignore all this if it occurs at idle!)

Sorry that has gone straight over my head buddy, can you expand a little(simplify to my level) so I can relate.

cheers for response guys ...

I hope it's something simple and cheap for you Bowders! Does seem a little odd that all was well before mind!!

I am running the std plastic water pump that was replaced less than 10000 Miles ago along with the cam belt, so think i can rule that out unless i have had a catastrophic failure.

I wouldn't rule this out. When I bought my vRS (new) the original one lasted less than 8k!! I only use the brass impeller pumps now.

If the temp stays at 90 degrees on tick over but raises when you rev it above 2k it's a safe bet that it's this that has gone for a $hit.

When the little green temp sensor is on its way out, this also makes the gauge jump all over the place.

Steve

Bowders; STSkoda is saying that your tuned 1.8T is capable of generating the sort of heat output in the cylinders at peak power revs that would generate this sort of heat energy to achieve 3Cdeg/sec heating of the engine system.

What he's ignored is that not all of the waste heat is rejected into the engine, coolant and oil. A significant amount of it (ISTR 50% of the total) exits as exhaust gas too.

I still think block temp sensor, not least because the engine fan sensor is completely independant of the block temp sensor, dashboard guage and EMS. Also, the block sensor has 2 output channels, one for the dash guage, and a separate one for the EMS. I think that VCDS only tests the EMS channel.

kudos to ken...he knows his stuff!!!

sorry to here that you are having probs mark, keep us updated!

Bowders; STSkoda is saying that your tuned 1.8T is capable of generating the sort of heat output in the cylinders at peak power revs that would generate this sort of heat energy to achieve 3Cdeg/sec heating of the engine system.

What he's ignored is that not all of the waste heat is rejected into the engine, coolant and oil. A significant amount of it (ISTR 50% of the total) exits as exhaust gas too.

I still think block temp sensor, not least because the engine fan sensor is completely independant of the block temp sensor, dashboard guage and EMS. Also, the block sensor has 2 output channels, one for the dash guage, and a separate one for the EMS. I think that VCDS only tests the EMS channel.

Hi Ken, yes I hadn't thought about that. tbh if this is a big problem I think the engine would be very likely to sieze if it was seriously overheating.

Some of the wiring to the fans have been known to be dodgy in the past so I'd be getting that checked if the fans aren't kicking in on a slight overheat at idle

STSkoda, Ken and Steevie cheers for those comments to consider.

I am best hoping dodgy Temp sensor and not water pump or even worse. Just could be coinsedence it happened whilst at MOT, so can't start blamming and could be just unlucky.

Won't know till Monday as they are very busy at the performance centre. They are very good folks at JKM so hopefully get to bottom of it.

had to cycle to work today god that was different...

do the fans work if you switch the air con on?, the fans shouldn't help cooling once the car is moving over 30mph or so anyway really, hot air from the heater? (normally goes cold when the pump fails due to no circulation)

any steam from the expansion cap?

do the fans work if you switch the air con on?, the fans shouldn't help cooling once the car is moving over 30mph or so anyway really, hot air from the heater? (normally goes cold when the pump fails due to no circulation)

any steam from the expansion cap?

Fans did not come on with air con. To be honest think the fans have not been working for some time

I also agree that when moving the car should stay a constant without fans which is what is was doing before i dropped car off.

Yes hot air from the heater.

No steam from expansion tank.

Cheers

Ouch, doesn't sound good

Pressured water won't boil until it reaches 130 degrees but even running at 115 isn't gonna do the engine any good.

If the garage you've got it at are specialists at performance cars then you've got to trust them. It could be anything really, fans (but i doubt it as why would the temperature be going this high ?) Water system, could be anything from a blocked radiator to a head gasket fault, could be a sensor fault and its not really that hot, just reading it is cause its faulty or many other problems, some big and some small. Sometimes the most costly side is the labour not the parts and if the garage are good at this type of car then you spend a better chance of them finding the fault quicker with experience then someone charging £10 per hour less but take and extra 2-3 hours to find the fault and replace some parts that possibly don't need changing.

Hope its not too costly a repair and doesn't take too long to get repaired but unfortunately a broken car is worth nothing and cycling to work in this weather is one thing but if the weather turns its no where near as pleasant as well as bloody tiring.

Good Luck

Regards Dave

Whats the latest buddy ?

not to bad or expensive I hope.

Bazza

Ouch, doesn't sound good

Pressured water won't boil until it reaches 130 degrees but even running at 115 isn't gonna do the engine any good.

If the garage you've got it at are specialists at performance cars then you've got to trust them. It could be anything really, fans (but i doubt it as why would the temperature be going this high ?) Water system, could be anything from a blocked radiator to a head gasket fault, could be a sensor fault and its not really that hot, just reading it is cause its faulty or many other problems, some big and some small. Sometimes the most costly side is the labour not the parts and if the garage are good at this type of car then you spend a better chance of them finding the fault quicker with experience then someone charging £10 per hour less but take and extra 2-3 hours to find the fault and replace some parts that possibly don't need changing.

Hope its not too costly a repair and doesn't take too long to get repaired but unfortunately a broken car is worth nothing and cycling to work in this weather is one thing but if the weather turns its no where near as pleasant as well as bloody tiring.

Good Luck

Regards Dave

Well my preference is to repair it, as most members on here know how fussy i am with the car and how i keep it maintained, but if the cost is huge then actually with what i have done to the car i could probably make more dismantling it and selling the parts, but not thinking that as yet.

Whats the latest buddy ?

not to bad or expensive I hope.

Bazza

Latest is that it is possible that the water pump impeller has either come off or disintegrated in the block. Checks were done on the sensor and found ok. This is not good news as i only changed that a year ago, so to me the part has failed way before expected. I will try and look at claiming back where i bought the pump. (Euro car parts I think) but i bet to make a claim i will have to get their preferred garage to check first. I can't be bothered with all that and just want job done. So perhaps I can claim the 3 hours labour and parts back later. Might as well get new cam belt whilst at it as you never know. Might even think about new stiffer engine mounts.

Even if the water pump gets changed I won't know for sure the head has warped or other issues arise, fingers crossed.

Good luck mate!

Latest news, the water pump is still intact however was showing signs of leaking and not working as such. So still early days, need the car put back together and tested.

Unfortunatley the water pump is none OEM which seem to fail more frequently than OEM. So I know what parts I will be buying next time! Also Audi,VW,Skoda dealers still recomend the OEM pump over the metal impeller one. So I am still going OEM as they have a 2 year warranty also.

Will update more later.

fingers crossed Bowders! Does that warranty also include if it fails and damages anything?

fingers crossed Bowders! Does that warranty also include if it fails and damages anything?

As far as I am aware yes.

I hope you don't break her as I'd end up spending all my money lol

Just read this post sorry to hear this,

you have helped so many of us on here with your mods / ideas etc

When I had my timing belt done at Unit 18 I stuck with a oem water pump replacement.

Like with all things you buy you take a calculated risk that you wont get a premature failure.

If it was my car I guess Id eliminate the cheapest bits first,

1/ Disconnect wiring to fans from main loom (if possible), then send 12v down each wire in turn and check that it arrives at fan (should eliminate a hidden break),

while flexing the wiring, maybe the strands have parted and touch intermittently.

2/ Over advanced timing causes overheating (not sure if its possible on the octy ie timing sensor failure)

2/ Replace the green water temp sensor even tho' it tests ok, reason :- it could be a transient fault that only appears when it gets hot.

3/ Remove cap from round expansion tank (engine cold), start car and look for any bubbling in the water, if seen h/gasket is leaking, if not gasket ok.

NB: My old R/Rover blew a head gasket on one of the heads, this caused a airlock to form and it overheated big time, after a run it smelt like a boiler room lol.

Hope you get to the bottom of this and its not too expensive

Peter

Cheers for comments, Peter

I have left the car in capable hands. JKM have seen my car a few times and offer great help and service. It could well be a sensor and maybe JKM swapped one over to see. At the moment the water pump seems culprit, and hopefully when replaced all is well. I did see a few bubbles in the overflow( :'( ) but put that down to the car at boiling point.

JKM did find that the fans were not working due to corroded wiring so this will need replacing, but for now i am concentrating on the overheating. I know fans have not been working for some time, but even them not working the car never went over 90 degrees.

Tomorrow I will find out :wonder: .

Also JKM noticed that my power steering fluid was red and not green(for the Audi TT rack) :S doh.. hold my hand up to that one.