Help No Cooling Fans 1.9tdi 110bhp Mk1 Auto

[octo0072000]

Hi all needs some info on the cooling fan wiring mine don't seem to work There are 2 sensors in the top hose, one nearest the head supplies the gauge and the ecu the one in the top hose nearest the radiator does the third fan speed and air-con My fans don't seem to work at all if i short across the pins on the top hose 1 fan goes full speed when I plugged in vag-com no faults found apart from air-con no gas also been having problems running too cold changed the thermostat now seems better temp up to normal or just above this gal has three relays near N/Side headlamp also has 2 big round long resisters under battory looks like same wiring from fans

when i got the gal one wire was broke off sensor in top hose 3rd fan speed so resoldered that any ideas anyone

:lol: :angry2: :unsure:

[chrispb123456]

Cooling fans will only kick in when required E.G engine temperature higher than normal, having said that if your aircon was working normally then you will see the fans running on the slow speed all the time aircon is switched on, or on the auto setting if you have climate control.

[octo0072000]

thanks Chris

what i am after is what senser triggers the fans or is it the ECU it self so i can trace the wiring i have now changed the thermostat the one i put in states 87c same as the one i took out but heating them both in a pan with a digital thermometer the new one fully opens at 90c the older one older one opens fully 85/87c on a run yesterday temp gauge got up to O of norm so i would have expected the fans to come in but no but on the same short run MPG on trip went up from 19 to 26 MPG so 7 MPG difference on a short 4mile stop then 4 mile again run is a big plus

on the diagram on elsa it show the senser near the head controlling the fans 1 2 the one in the top hose controls air-con and 3rd fan speed Haynes is no good on this elsa only gives me diagrams on my version with no part nos

[chrispb123456]

I think you are worrying unnecessarily the first stage fan will kick in approx 90+ degs second 95 to 100 and third over 100, with the cooling system under pressure this raises the boiling point to about 110-115 degs.

So before you get the fans to come on you will need to be stuck in traffic on one of those hot summer days lol if we get any this year.

This only applies to the diesel versions.

I'm sure some other members will confirm this for you.

[octo0072000]

I think you are worrying unnecessarily the first stage fan will kick in approx 90+ degs second 95 to 100 and third over 100, with the cooling system under pressure this raises the boiling point to about 110-115 degs.

So before you get the fans to come on you will need to be stuck in traffic on one of those hot summer days lol if we get any this year.

This only applies to the diesel versions.

I'm sure some other members will confirm this for you.

 

thanks Chris

might be worrying but don't want to set off for a day out and cook it

it's taken me now on and off 3 years to find a half decent MK1 ghia tdi auto body work has the usual scrapes and rims scratched body is very straight inside is mint 6 seater all with captains seats all works apart from air-con full history loads of bills etc

not many decent MK1s out there

[octo0072000]

quick update

temp gauge since replacing thermostat now seems to run at the Ron the NORM bit so just over centre on the gauge MPG has improved locally by at least 9 mpg on shortish runs so happy with that just need to fins a wiring diagram for the fans still don't seems to work at all so maybe another wire is broke i have repaired one on the top hose senser

getting there

the thermostat the was replaced was a VW/audi genuine one replacement from factor seems to open a bit later but both opened when heated in a pan new one seems to open about 3% later then the original one so never ever fit a thermostat without testing it

[bigdave982]

On my old mk1 it rarely got hot enuff for the cooling fans to kick in,had to be in traffic for ages. Seem to recall it being to do with diesels (in general)not producing much waste heat which is why mk2s have the aux heater to help things along. I would guess that if its going to overheat it would have by now.

Mpg has improved because its now running at operating temp ,not on cold settings(like leaving the choke in,anyone remember those??)

[octo0072000]

On my old mk1 it rarely got hot enuff for the cooling fans to kick in,had to be in traffic for ages. Seem to recall it being to do with diesels (in general)not producing much waste heat which is why mk2s have the aux heater to help things along. I would guess that if its going to overheat it would have by now.

Mpg has improved because its now running at operating temp ,not on cold settings(like leaving the choke in,anyone remember those??)

 

Hi bigdave

let me think Choke that's the little knob the ladies pull out to hang there handbag on

true story i had to go out with said dear in a Ford Anglia 1200cc super to access here driving and that's what she did

also worked for Vauxhall when they went to the FD victor it went from three speed gearbox to a four speed column change man complained about bad economy he went from Leeds to Glasgow and back in third gear both true i had to go out on road test with them me been in and about the motor trade for 40 odd years

 

 

my MK1 has booster heater too

but needs looking at glow plug i suspect that on the to do list