1400 familia pickup over heating
 

Hi there,
I have a little 1400 pick up with a UC engine here in thailand and it seems to be running hot ie the temp gauge right near the top after about 5 mins of driving. But i hasnt boiled over yet...
I have checked and tried a few things.
1. Coolant flush and bled system
2. Replaced the viscous fan with a very powerful electric one
3.removed thermostat
4. Remade connections on the sender
I have 3 ideas either the temp sender is faulty? Does anyone have any resistance readings for one?
Or
Replace the radiator as it possibly be clogged
Or
The head gasket has gone
If anyone has any bright ideas or more info please let me know
Cheers
Colin

What year is this, how old is the radiator? I replaced the factory radiator on my 1988 B2200 about 8 years ago, it also was running hot on highways. These do get clogged over time.

Running hot in city traffic/low speeds can be indicative of cooling fan/fan clutch.

Removing thermostat is only for testing, won't cause it to run cooler.

Any smoke out the tailpipe, loss of coolant, or milky oil? Some symptoms of a bad head gasket. Also, a cylinder leakage test could confirm/eliminate head gasket leak.

Its a 1989 but still the old rwd setup. From what o have seen there is no indication that the head gasket has blown, there is no mixing of fluids, no smoke or steam out of the exhaust and no over pressurising of the coolant system. So it looks like it will be a new rad as ive already flushed the old one.
Cheers for the quick reply

Ok so today i replaced the sender unit and the gauge has dropped while running which is good but....
It is still running hot so next step will be the rad : it looks like the original which has had a few previous repairs.
Just want to get this sorted so i can use the air con again

Yep, new radiator, install thermostat, bleed ALL the air out of the cooling system (jack up front end, run with cap off, keep adding 50/50 coolant as necessary, might take 20 minutes or more).