Strange gremlins - Mk1 Golf GTI (1983)

Hello all,
Hoping I can get some help on some odd issues - aren't they all odd when car gets to this age .

Car is well serviced, Mk1 Golf GTI Campaign.

Battery is about 18M old - Bosch unit.

1. Issue 1. When I leave the car for say a couple of days - sometimes the MFA screen freezes - can't select any option beyond time, or the clock changes, or sometimes it seems to cycle itself through the MFA settings (only seen that the once). Other times I leave it fpr a frw days - no issue! Disconnecting battery generally addresses issue and I set clock to correct time .
2. Issue 2 - last year or so the temp gauge shoots up to MAX and red LED flickers in the gauge. Have changed the coolant sensor - no change. Does it sporadically - may not do for 2 weeks, and sometimes on a drive does it, then stopes doing it, then does it again!! Coolant is new and all the bits changed recently: fan switch, sensor in header tank, radiator, water pump, thermostat.
3. Issue 3 - last couple of months when engine cold the oil buzzer comes on - again oil pressures are good and oil is new(ish). Turn off ignition, restart and then it stops. Some days it does it - others does not.

So issues all seem to be dash related - could it be an earth issue? Any thoughts GTI experts out there?

Cheers
D.

Welcome to the world of old Mk1 electrics.

1. My GTI has done that occasionly for the whole 24years I've owned it. The outside temp also usually lies and the MPG is usually double the real value or 99.9. Pushing the button on the stalk doesn't do anyhing then its ok then its not. It's never cycled thru on its own though.
2. My GTI has started occasionly flashing the red temp gauge LED. My GTI is an early 1800(!) so doesn't have the level sensor in the header tank which is the cause of many of these false alarms.
3.. My GTI does that sometimes, think its the clocks as it's usually when its been parked in the sun baking the dash, tapping the clocks usually does makes it stop.
4. A new one to add, the yellow change up LED has worked about 3 times in the time I've had it. I did fix it for about 5mins by changing the little round vacuum switch thingy near the dizzy. Turns everyone that has one that works hates it, flashing lights on the dash are a bad thing.

the temp gauge LED may be due to a capactor(?) failing deep inside the gauge itself according to some stuff I found on a same era T25 forum

the instrument voltage stabiliser is often blamed for weired things happening with the dash clocks along with bad earths, esp the one to the engine camcover in the engine bay

If you haven't replace the main Battery to frame-frame to engine earth (grounds) you may want to do so.

You can use 2 off the shelf cables from a parts store, as I have done in the past.  The Valve cover to Coil bracket ground may be corroded or missing that is a big cause of flakiness on a MFA.  If buying replacement cables you can get the ones with the extra Pig tails, and can do away with the ring connectors on the nuts.

The water temp gauge can go flaky.  They have a tendency for the posts to get cold solder joints.

The blinky light from hades for the oil is usually running to thin oil, and or a Generic, Bosch or Fram filter.
In my rides I run 20W50 oil, and a Mann, Mahl, Pureolator Gold, Mobile1, or Genuine VW filter.  All others are garbage.

I have a bunch of how-to's in the Archive section. See my Signature link.

www.cabby-info.com is a good source of Cabby information.