Mk1 Temp Issue

[LCR55]

Firstly a HI from me a new member with a mk1 Cupra R on 2004.
I have trawled through quite a few threads but still no wiser (sorry)
Basically the temp gauge rises to 3/4 and then the fans (both of them) kick in and get the gauge back to around just over half way but a couple of minutes drive and the gauge again will rise to the 3/4 mark.

With the A/c on both fans are working, heaters nice and warm, coolant levels fine etc.
Had a look on the menu in the climate control and even when the gauge shows 3/4 up the climate control reading for engine temp stays at 90c

Any help grealtfully received.

Have ordered a new CTS as it seems the easiest / cheapest item first to check.

 

[mty12345]

Hi there, welcome to the forum.

Sounds like maybe the "slow speed fan problem" Have a look here http://www.seatcupra.net/forums/showthread.php?t=434936

The temp on the climate control is just the "back-up" temp map that the engine uses incase the real temp isn't availible. Hence the reason it just stays at 90C

And here http://www.seatcupra.net/forums/showthread.php?t=331943

 

[LCR55]

Hi and thanks for the reply - I did read that post but some mentioned their fans don't work with a/c on and mine do which is why I thought it may be something else..

Eitherway looks like I'll have to find someone to do 'the fix' to rule it out.. I don't fancy gettine a nime as it only works with a/c on..

Cheers

 

[LCR55]

Going to try the radiator temp sensor first and failing that then look into the fixes above !

 

[LCR55]

So tested the fan switch direct and with car started both low and fast speed work fine. So replaced the Fan switch (Thermoswitch) and the coolant temp switch as i'd bought both and still the same... Temp needle goes 3/4 way up.
Having further read some more threads on here i'm leaning towards the water pump......?

 

[frijj]

I am also having this trouble and done exactly what you have. I concluded that it is the water pump.

Check the return flow of coolant back to the reservoir globe. Do this by removing the small return pipe on the globe, holding it into the reservoir have someone start the car. Let it Idle, take note of flow. Tell them to give it some revs (2-3k) take note of change.

I get good enough (not great) flow at idle, but any revs and the flow suddenly gets slower until it drips out.

 

[LCR55]

Yes did a similar test and on idle was ok when revved ok but when revs dropped it spluttered. However after a few mins was fine..

 

[LCR55]

Well had the waterpump replaced and timing belt changed and unfortunately problem still there...
So my fans kick in when the needle reaches past half and before the 3/4 line.

WHen I pulled the thermoswitch off and on ignition get both fan speeds working so unsure as to what the issue is... With A/c on both fans remain on constant (not pulsing like suggested in thread for slow fan speed fault).

Any ideas people as i'm getting to a point of selling the car now as I hate driving when its not 100%

 

[mty12345]

Hi again mate. Sorry to hear that you're still having issues.

Have you changed the thermostat? It's not classic thermostat syptoms, but for the sake of the £15 that one costs, i would definitely change it! It's possible that it is failing to fully open. That partial obstruction of the water flow would cause the temp to spike up until the fans have to step up to the fast speed.

If/when you've done the thermostat and are still having issues, then start by getting it on a obd2 reader so that you can monitor the real temp as you drive. The temp that it hits when the fans kick in will probably be helpful in diagnosing the issue.

 

[LCR55]

I did mention the stat to the garage but they said as the heaters inside the car are blowing hot they didnt think that would be the problem...? They had a computer on it prior to doing the waterpump change and i think it was around 106 when the fans kicked it..

 

[Muttley]

Do you mean that your fans did not come on until the temperature reached 106°? That is the temperature at which they should run at high speed. The thermoswitch is meant to perform as follows:

Low speed
on: 92...97 °C
off: 84...91 °C
High speed
on: 99...105 °C
off: 91...98 °C

Both fans should come on, go to high speed, and shut down at the same time.

I assume you have an aftermarket temperature gauge, as the behaviour you describe is not normal. The dashboard gauge should go round to 90 and stay there unless something is badly wrong. The CTS actually contains two sensors, one that goes to the dashboard gauge (a 12V system) and one that goes to the ECU. The dash gauge is very low-res, and should as I say stick at 90 all the time. The ECU sensor is more sensitive and feeds precise information to the ECU.

If your dash gauge is spending a lot of time below 90, then you've got your thermostat stuck open, at the very least.

 

[LCR55]

Hi and thanks for the reply. The gauge is standard as per the car. It shows it on 90 (1/2) but as the fans dont come on until later they gauge goes past the 90 and towards the 3/4 line which is when the fans cut in and goes slightly back towards the 1/2 way mark (90)..

Once the engine is warm the gauge does not go behind 90. ALway remains on 90 or towards 3/4 ...

Both fans come in and go off together. It 'sounds' like the slow speed comes on late at around 106 as when the car is switched off and the thermo fan switch terminals are bridged I can get both fan speeds to work which to me seems the fault is not the usual slow speed issue as all the threads I have read when people have similar overheating issues and test the fans direct via the rad fan switch (thermoswitch) they only get 1 speed to work which the high speed. AS mentioned I can get both speeds to work on mine in this manner..

Cheers

 

[Muttley]

Apologies, I was misremembering the way the temperature gauge looked in my old Toledo's - you're right, 90 is halfway on the gauge.

As you say, not the usual slow speed issue, which is caused by the slow speed resistors burning out. It almost sounds as though you are not getting the slow speed signal from the thermoswitch to the fan control module. May be a wiring fault or the fan control module itself. They are expensive, so try to rule out everything else first.

If possible, see if you can test the thermoswitch signal as the car warms up. If you get the low-temp switch coming on but the fans don't go, then it's wiring or the module...

 

[LCR55]

Hi how can I test the signal from the thermoswitch? When the car was cold I removed the plug from the switch and bridged the terminals and got both high and low towork which is why I tuled the issue of a faulty slow speed fan issue, hence went on to changing the thermoswitch and then the waterpump.

 

[LCR55]

Been away woth work and not had a chance to do anything as yet.. Can anyone tell me how to check the signal from the thermoswitch to the fan module? Or shall i buy a replacement module (ebay copy parts are $40 ish and 2nd OEM ones are £20)

 

[LCR55]

Got a fan control unit (2 plugs going to it and sits to the left and under the battery tray) off a mates car and problem still there so am cutting my losses and selling the car now as I dont have the time / knowledge to get it sorted unfortunately.