Overheating '85 MK2 1.8 kjet

[llewellyn.xavier]

Ok guys I hope you can help me as I am at the point of losing it, on my '85 Golf 2 I have constant overheating, the car goes to 3/4 temp and the temp light flashes, and I can't figure it out, here is some background.

I have just gone through a engine overhaul as one of the main bearings gave out, entire engine was stripped, and steam & pressure washed, all ports where pressure washed as there was corrosion from all the years (engine was last stripped in the 90's), pretty much the entire engine was completely cleaned, rebuilt and replaced engine, water pump and thermostat are newish (replaced November '18) all hoses were also cleaned inside before fitment.

Radiator has been flushed and flow is great thru it, running on 50/50 coolant mixture, fan thermoswitch works kicks in at about 1/2 gauge, full speed fan kicks in at 3/4 gauge, small return pipe has been cleaned and flow seems fine.

Driving on open roads at constant speed doesn't drop the temps, fan doesn't keep the temp under control as traffic makes it run up to 3/4, both upper and lower radiator pipe are hot, although lower pipe seems to be under less pressure/have less water in, I've bled all the lines as best as I could.

The only things I believe it could be is either a air bubble in the pump by the thermostat, or a faulty thermostat, I will by a thermostat at goldwagen Tomorrow as the Midas near me didn't have one today and replace that.

Failing that can anyone think of anything else that could be the problem



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[MarshallGTi]

Thermostat - faulty or perhaps wrong opening temp
Water pump - could also be faulty no pumping enough volume
Radiator - is it the correct long one and is it a decent quality brand like Behr or Plexus?

Otherwise if the problem only started after the rebuild then you could have a problem with an incorrect head gasket or something along those lines.