Cooling a 2.0 16v - rad fan (new switch fitted..)

[Jim 2]

I'm not entirely happy with the temperatures on my 2.0 16v, and more specifically not happy about what temperatures the car gets to before the radiator fan comes on.

 

In the last 6-12 months i've fitted a new VAG radiator, thermostat, VAG water pump, and VAG radiator fan switch - car is using a good mixture of G12+ so there is absolutely no reason it should be struggling even in this mild heat. But putting the car away this evening I was worried to see the oil temp crawl up to 114 degrees and the radiator fan wasn't even on. The only time the rad fan comes on is when the coolant temp gauge gets to 110 centigrade and even then it just comes on at really low speed. It just doesn't seem right to me.

 

Now there are a few interesting things here. My car used to have a different radiator fan switch fitted from a different car - the connector shroud on the fan switch had been butchered off to make it fit, and I believe looking at the temps printed on the side it was designed to come on MUCH sooner and keep the car cool. I replaced it with a new (and correct for the car) one which has much higher temps but i'm not sure its doing its job properly - in fact i'm hoping I kept the old one so I can refit it!

 

What I want to know I guess is, is there anything else on the 2.0 16v that governs the radiator fan speeds / what speeds come on when, or is it simply down to that little fan switch in the radiator? Is that what is causing my problem?

 

Cheers.

[Supercharged 2]

Thats the sign of a knackered fan switch mate but sounds like the wiring in your case needs looking at...

[Jim 2]

The Haynes manual reckons that simply bridging the earth and live pins on the fan connector should put the fan on - if that works, you can pretty much rule the wiring out... so thats step one I guess.

 

Its quite possible i've been supplied the wrong radiator fan switch by VW.... there was a bit of confusion when I went to my local dealer about it so who knows..

[nocrap 0]

I think there's only 2 options for the rad fan switch one with 3 pin orientation in a row the other with the middle one set higher....

[Jim 2]

Yeah - saw that at the stealers mate. So it seems like there is only one suitable fan switch from VW... weird.

 

Interesting thing is though these guys do a high and low temp fan switch suitable for our cars...

 

http://www.germanautoparts.com/Volkswag ... ling/208/1

[Toad 0]

Try bridging the connectors and try to borrow a infra red thermometer, just because your gauges say a certain temp, doesn't mean you are actually getting to them.

[davidwort 0]

Yeah - saw that at the stealers mate. So it seems like there is only one suitable fan switch from VW... weird.

 

Interesting thing is though these guys do a high and low temp fan switch suitable for our cars...

 

http://www.germanautoparts.com/Volkswag ... ling/208/1

 

I'm sure one of those switches is from a Transporter or something random like that Jim, the 16v should operate quite happily on the standard Corrado item.

I'm with Toad, you need to get an accurate water temp reading by some other means, do you have more than one water temp sensor of the same type on the side of the head for the 2L? if so swap them over and see if the reading is the same, you could also remove the rad fan temp switch and heat on the hob in a pan of water, connecting a multimeter to make sure which paths are switching at which temps, boiling water will give you 100 degrees, from memory the 2 circuit should switch 5 or so degrees apart, something like 102 and 107 degrees.

[Jim 2]

I'm fairly convinced the car is reporting the temperature correctly. The MFA coolant temp sender is only about a year old and was sourced from VW. The fan switch in the radiator is only 5 months old, and is again a genuine VW item. Are there any other temp sensors I should look at switching though?

 

The curious thing is that sometimes the fan will be on when I don't expect it to be, and then sometimes when the car has been REALLY hot the fan hasn't been on..

 

I'm still wondering whether i've been supplied the wrong radiator fan switch from VW. With the low temp sensor I used to have fitted, the fan would be on after my drive home most of the time which kept the engine at normal temps. The last few weeks have been the first real warm weather we've had since fitting the new fan switch so its no surprise this is the first time its possibly shown itself up...

[Supercharged 2]

Could be faulty mate - got the part number so I can check it??

 

If it's 3 pins in a row (---) I have a known good spare I can send you.

[davidwort 0]

you have the fan relay setup nr the washer bottle on the 2L don't you? I wonder if they could contribute any problems?

[Jim 2]

Could be faulty mate - got the part number so I can check it??

 

If it's 3 pins in a row (---) I have a known good spare I can send you.

 

Hi mate - that'd be handy. Will have a look through my reciepts box file tonight and see if I can find the reciept for it! Will know if i've bought the wrong one or not then!

 

you have the fan relay setup nr the washer bottle on the 2L don't you? I wonder if they could contribute any problems?

 

I'll need to check mate - will have a look when I drive the car home later :) Thats one of the things I was trying to establish - just what else goes into the fan circuitry on the 2.0 16v! My usual technical incompetence is shining through here! :) Could a relay have gone or something, that could be causing this?

[johnnyfication 0]

The 9a has a large relay/fuse next to / in front of the coolant reservoir that is on the fan circuit, I had to change this on mine as i had high temps and changing temp senders etc didn't help.

 

HTH

Jonathan

[Jim 2]

Excellent. I'll look into this mate! :) :)

 

Mysteries of the mishmash that was the 9A are gradually coming out!

 

I'd be really really interested to know if this has anything to do with my flashing coolant light as well - I can but hope!

[easypops 8]

The 9a has a large relay/fuse next to / in front of the coolant reservoir that is on the fan circuit, I had to change this on mine as i had high temps and changing temp senders etc didn't help.

 

HTH

Jonathan

 

Just a wee input from a fellow 2.0 16v owner....who has looked for the mysterious missing relay/fuse... :shrug:

its not here on mine :gag: :lol:

[Jim 2]

Can't visualise what my bay looks like - totally forgot to check last night! Will go have a look at lunch time and see what's what! :)

[davidwort 0]

something like this Jim, but hopefully with an engine, relays arrowed.

[vwdeviant 0]

Yup my 9a has those relays there too!

 

Jim, in the (coming up) 3 years that I've had mine my oils always sat slightly on the high side (110-114) on the move, but apparently (according to my mechanic) that's more than likely down to an old sender, oil's changed and comes out looking fine not old and thin.

 

The Rad fan kicks in at 110 too so think this is right as well, strange thing is mine normally sits with W/temp at mid-gauge (90?) but last Saturday, on a beating up the A12 following an SLK in the heat, it was constantly showing slightly lower (about 5-7 deg) wehther moving or in 40 mph traffic, which was wierd... :confused4:

 

I wouldn't stress too much about it.

[Supercharged 2]

The Rad fan kicks in at 110 too so think this is right as well

 

That means the thermoswitch is only working at the second stage (ie it's 'failed safe') - cheap and easy part to change (30mm spanner needed)

 

1 = 84-91c

2 = 95-102 c

[Walesy 0]

Check it first though as the fan could be running stage one without you hearing it, it's only really loud and noticeable when the second stage kicks in at 110deg

 

RKE have one of those infrared thermometers, most cars i've had have been indicating that they're running hotter than they actually are. It seems that keeping the temp constant on 1990's VW's isnt to easy tbh, i've had trouble with countless cars that run hotter than i'd like but dont overheat :cuckoo:

[Jim 2]

Temperatures on my car have been all over the place for various reasons since i've had it. Things have been changed in stages, and for a while the car always ran SUPER cool - I think that was because the thermostat was stuck open and I had a low temp fan switch installed. Its only now that everything has been changed out that i'm running into problems! Typical!

 

Tonight the fan only seemed to come on once the coolant got to about 110 centigrade again so the rad fan switch or this relay do sound like very likely candidates. Oh... and I do have those relays as per the picture - i'll have to have a poke about and look for this elusive fan relay.

 

Check it first though as the fan could be running stage one without you hearing it, it's only really loud and noticeable when the second stage kicks in at 110deg

 

I've knelt down next to the front of the car with my ear next to the grille and not heard the fan.. i'm pretty sure its definately not working at the lowest speed :( If parked up the temps just crawl quite steadily to the 110 mark before the fan actually wakes up and does anything! :(

[Supercharged 2]

Jim - I thought you said the wiring was suspect - have yopu checked the 3 wires to the fan switch??

[Toad 0]

I think I might have one of those control boxes. We can have a ferret around on Saturday if you want?

[Supercharged 2]

I'm all up for ferret action mate as you well know but this thread is about Jim's water temp issues...

[Toad 0]

I'm all up for ferret action mate as you well know but this thread is about Jim's water temp issues...

 

Well, I was hoping to combine the two by catching Jim in a rare, looking under the bonnet moment...

[Supercharged 2]

I don't think he is participating tho in the spit-roast action (well, not round yours anyway...)