Overheating problems, Fan not kicking in

Hello all,

I have an 84 1.1, which is having over heating problems. It hasn't fully overheated yet, but the temp gauge sits very high when stationary. Water vapor is also escaping from the rad cap too.

After looking at posts on here i have replaced:

Thermostat

Temp Sender

Fan Switch

Rad Cap

But still no joy. The fan used to kick in when shutting down the engine when i was running the old thermostat but with the new one it doesnt do this.

The fan seems to be operating fine when i pull the clips off the fan switch and touch them together.

Any ideas on what to do!?  :dontknow:

Many thanks Dan

it'll be the temp sender on the rad i just ran a switch to the inside on mine.

where is the temp sender on the rad?

I replaced the temp sender that was on the reverse of the thermostat housing

Update, i have tested both fan switches i have by dipping them in a mug of boiling water.

Both were unable to kick the fan in, the one i brought the other day was from euro car part.

Not sure if i should try a vw fan switch, or may just wire in my own switch

clean up the terminals that connect to the sensor in the radiator and make sure they are tight when pushed on.

I was told by someone that it doesn't matter which way round they are connected up ie you can have - to + and + to -, but my fan only works when they are connected up a certain way I'm guessing - to - and + to +.

Just tried that, still no luck.

Looks like ill be making a switch tomorrow!

i just bought a rear heater switch painted it black and wired it to that in the blank space.

Have you tested the switch, while its installed in the radiator, and heating your car up? And eliminated the thermostat from the issues (by checking top and bottom radiator hoses)?

Top and bottom radiator hoses get very hot. And the heaters work fine.

Ive tested both switches separately by putting them in boiling water but they did not operate the fan

If the fan comes on when you touch the two wires that connect to the sender in the radiator together then it can only be that sender switch in the radiator as you've already proven that every thing else in the circuit is working.
A cup of boiling water probably wouldn't get it to work anyway as it will cool down too much before you get it outside, the thermostat on the cylinder head opens at 85+ degrees C so I would have thought it needs to be hotter than that or of similar heat to get switch to work, and I doubt your cup of boiling water is hot enough.

I was going to say ive spent all day rewiring it and it still didnt kick in when i tried boiling water.

So ive got a switch in now.

Where abouts is the correct placement on the temp gauge for an average engine temp?

My old gti was half way, but this one seems to sit a third of the way along

Ok the same problem is still happening even though the fan is now on a switch.

Its also a little thirsty for a 1.1, i think 30 mpg is a bit high for it.

Anyway i give in, so im now going to get rapped by a local garage!

So the fan works fine when you temporarily supply 12V to it, but it doesn't work when you've wired a switch to operate it? Check your switch wiring!

No it works on the switch fine.

I just still have the over heating problem

I had a very similar problem with the fan not kicking in on my 1978 1.1 Golf. It did work and then one day I watched the temp needle go way to red and the fan was not kicking in.

I connected the back of the fan to the battery and it kicked in fine so I suspected the rad temp switch was faulty. I replaced it with a new one from Euro Car Parts and I still had the same problem.  I cleaned all the connections (especially where the earth wire comes out the back of the switch and secures to a post on the inside wing) - still the same problem.

I gave up and took it up to the local garage only for them to call half way through to say the fan was kicking in ok. They acknowledged that the temp needle on the dash did go very high but said not to worry as long as the fan was kicking in.

I will get around to changing the temp sender on the side of the engine which hopefully will not allow the needle to go so high but at least the fan has been working ever since.

I can only conclude from all of this that all connections have to be clean and secure - double check them - as I think this is what caused the problem in mine.

When I have the time I'm also going to wire in a manual override switch for the fan just for peace of mind.

As long as the little red warning light isn't flashing it's not a problem.

The fan should kick in when needle is about 3/4 of the way up the gauge.

I guessed that it would be ok, its just annoying that i keep getting steam from the rad cap, but i dont seem to be loosing any coolant

So you don't have a problem then do you !                  

The hotter the engine runs the more efficicient it will be !
If you are really that bothered about getting it to run cold(er) all the time without having the fan on a switch and running constantly then look at getting a replacement thermostat for in the cylinder head housing that opens at a lower temperature and a temp sender for the radiator which also switches on at a lower temperature.

lol i dont really want to be sat in traffic watching steam come out of my bonnet. And at the end of the day it shouldnt really happen.

Thinking i must have a blockage in the rad, flushed it with rad flush but still no joy.

Going to get a new rad, see what happens!