Golf MK1 GTI 1.8 DX - Radiator fan not coming on!

Hi folks, hope you can assist!My MK1 GTI 1.8 DX radiator fan stopped working last week whist driving through town.

The oil temp on the MFA was reading 177. I managed to pull over and let the car cool down and run it back home.

I checked the fuse which was okay and replaced it to be safe.

I have now replaced all three item below.

The thermostat in the water pump.
Thermo switch by the head
and the radiator switch.

The car is still continues to overheat. I have ran the car up to temp with the cap off and squeezed the pipes to clear any air locks. The water clearly flows back into the expansion tank.

I have disconnected and bridged the two red wire going in to the radiator switch and the fan does come on.

I have also tried a different fan wire I had in the garage from an early 1.6 which had the positive and negative connection directly to the car battery.

Still no joy!!

Can anyone throw me any advice?

I'm guessing it's got to be an electrical issue.

Would be much appreciated - gorgeous day….just want to drive her again!!

What year of Golf/Cabriolet are we talking about?

You should match the Radiator Fan switch to the t-stat a miss match isn't good.

Did you test your Radiator Switch (I know new) before you put it in?  As I have seen bad ones out of the box.
What was your water gauge reading if the oil was at 177?

Was the car actually overheating coolant wise?

How was the oil temperature reading 177 when they jump in even numbers? should read 176 or 178. That is a very high reading, I've only ever got my oil to 130 after a long hard motorway run.
150 is in the danger zone and normally 90 is a average reading with oil getting to 100 ish if stuck in traffic.
Have you checked to spade connector going to the oil temperature sensor as they have a tenancyto be hanging onto the wire by a couple of threads and not reading correctly.

What was your coolant temperature gauge reading?
Does the lower radiator hose get hot and is the last hose to get hot?

Did it actually boil up and loose water?

Isn't there a sensor/switch on the bottom left of the rad on the DX engine?? 

Knowing if the Coolant was hot, as in does his water temp gauge work… is paramount to understanding what is going on.  

If the coolant wasn't in the RED or at 3/4 then the fan wouldn't come on.

He also didn't state the YEAR so we don't know if the car has a water cooled oil cooler, or that he needs to install a External Oil Cooler.  

My Automatics, run hotter than the Manuals, and I added an external temp controlled cooler, I now see my oil on a hot day (104f) the road is about 150f.. never get above 114 on the oil.

Hi,

Apologies my car is a 1983 Tintop MK1 GTI Campaign.

By reading previous posts, This morning I tried removing relay 43 from the top of the fuse box. Ran the car on the driveway for 10-15 minutes and let it reach temp

Hey presto the fan came on.

I've just taken the car for a drive and all seemed ok .

On the return journey the oil temp starting reading 173 and I noticed the fans not kicking in.

The car seems to be running and idling ok. However when I let the car cool down and pulled the dipstick I noticed some mayo. Does this mean the a head gasket is about to go?

Can it be saved with a instant head gasket thing in a bottle?

Condensation in the Oil isn't indicative of a bad head gasket.

When you run the engine on short tests, then it cools condensation occurs in the block….

If you don't drive it for long drives getting the block and the oil up to temp to "Burn or Boil" this moisture out you may see this….. "So while it is normal" other things to consider to test it.

1. Do you have a Water filled Oil Cooler on your car.  It is a Square box that sits below the Oil filter flange and the Oil filter.  One hose goes to a "T" that is in the heater bypass line, the other to the water outlet flange on the grille side of your engine.



2. Here are a couple of tests for you.
Cold engine as in let it sit overnight or till completely cold.

Open the Expansion tank look to see if there is a oily ring at the water level.  if so then,  tie a Latex glove or ballon over the open hole.

Start the engine, then under the hood raise the RPM of the engine to above 3k for about 30-45 seconds, if the Glove inflates and gives you the finger, bad head gasket.
This test is only good for 30-45 seconds as the heat of the coolant and expansion and steam will auto inflate the glove after about that time.

Hot test… When you have driven your car and gotten it up to temp….. leave it running, then open the hood and Squeeze the Upper Radiator hose.

If the hose is Swollen or Hard to PRESS or Pinch
Then possibly a bad head gasket.

Do the cold engine test.

If you have the water filled oil cooler installed, these have been know to go bad and intermix Oil to Water, usually not the other way around.  Why because Oil pressure is greater than the 14psi on a cooling system usually.

So if the hoses swell and the Glove inflates, then you have either a bad oil cooler if installed, or a bad head gasket.
I would replace the Oil Cooler first if installed as it is Cheaper, and is easier replaced than the Head Gasket…. Don't forget to purchase the o-ring.
 

if oil temp got that high then i would suggest you have a short in the wire, 177 is WAY too high I would expect serious engine damage

look for the small white sensor in the oil fitler housing, it should have a green/black wire. check all that is in good nick

the radiator fan should only cut in if you are sat still for a while, as previously mentioned the coolant temp gauge should be about 3/4 before it starts