Mk1 golf 1.6 getting excessively hot

So…. I drove 200 miles yesterday without a hitch, apart from it got a lot hotter than usual. This wasn't due to traffic, as it was all motorway miles. I kept it at 60 but even now on short 5/10 minute journey it creeps up to just over 3/4 on the temp gauge. 

Where do I start? Gutted! 

Any help appreciated

And now it's fine….

I'll have a good poke around in the morning. I done a coolant flush a few weeks ago so it may have some locks.

this may help, only thign to add in a mk1 be sure heater is set to hot when bleeding. but i assume its never set to anything else this time of year
http://www.vwgolfmk2.co.uk/forum/viewtopic.php?f=37&t=14913

Sorry I've not responded to this. Rubjonny I reffered to your guide as default, I remembered it from my polo days. Alas I've demolished my back and have been out of action for the last week and I've been signed off until 22nd February, so golf progress has grinded to a hault.

Swings and roundabouts, I'm in agony, but I'm online shopping for the Mk1.

Anyway….

I followed your guide and I'm 99% there's no air locks in the system, but stationary the temperature got up to around 80/85% and the fan didn't kick in? Which is odd, as I've definitely heard it running in previous days. I've not let the car get to the point where it starts to act erratically and over heat, as I've been down that route before, but it doesn't seem like the gauge is reading very accurately? For example I'll be doing 50mpg and the gauge will stick at 80% but when I slow for a roundabout it drops down to around 30%? Which makes me think its some kind of temperature sensor, or at least a series 1 equivalent of one? Also, when it gets hot, I slam the heaters on and after a little while its dragging through luke warm air at best, where as if it was getting hot, the heating would be pulling through properly hot air.

Another thing of note, is its getting through oil, but this maybe due to the rocker cover leaking.

On the bright side…. I've bought some postie lights, in the typical fashion of ignoring the problem.

hmm, the fact the heater is not working well makes me think the thermostat was removed, which could have been done by a PO who thought the car was overheating due to the gauge over-reading or being erratic like you describe.

the sensor is the small black one in the front or side flange with a red/yellow wire, start by checkign the spade on this and buff up the contacts

Cheers. I'll have a look tomorrow morning, I'm a bit more limber now as I visited an Osteopath today.

I'll post back with my findings, where it the thermostat on this anyway?

its in the waterpump, if you follow the bottom radiator hose to the flange on base of pump its behind that

Today I've been driving it and its shown absolutely no symptoms of getting hot, the temperature gauge remained at a good level.

I think it does have the thermostat in place as when I ran it from cold and bought the car up to temperature the bottom radiator hose stayed pretty cold until it got up to 3/4 and then it released became hot.

I would expect the gauge to stay at 1/2 at all times, and the thermostat to open before the gauge starts to rise above 1/2 so the stat could be sticky? It could be as you say the sender isnt quite right, have a look in the coolant flanges on the head for a black single pin one with red/yellow wire thats the sender for the dash. make sure the spade is clean and the wire is in good nick.

with the cool heaters maybe theres something up with the matrix or the heater valve. to start with set the heater to hot then pop the bonnet and physically check the valve is fully open, if it can opened a bit more by hand a bit more try popping the cable retaining clip off, moving the valve and heater knob to 'hot' then refitting the clip.  if the clip is missing, well thats probably the issue

also have a feel of the valve operation, if it feels really light and moves without any real resistance perhaps the lever and flap inside have parted company.

to test your rad fan unplug the 2 wires from the thermoswitch in the rad and jump them together with wire, if the fan runs you know all the electrical side is ok but the thermoswitch might be shot. next time the gauge gets to 3/4 have a feel of the rad to make sure its getting hot all over, especially the area the themoswitch is sat in.

if the fan doesn't run buff up all the electrical contacts and check the fuse. also jump the fan with 12v straight off the battery to check that it actually works!