Overheating, I am stumped

I am coming down to the same thoughts as others that your troubles are all related to airflow and a rad. that is to small. That bumper is huge and will effect the flow of air to the rad. and the extra lamps, although a reasonable size, will cause turbulence to a smooth flow of air. IMHO a rad designed for a 1300cc engine is likely to be too small for a 1600cc variant, especially with high ambient temperatures.
Is it practical to remove the bumper to take a test run?

Roger

adding my 2 cents to the convo also, i had much the same issue and ended up upgrading the radiator to a 3 row from ebay, afterwards we actually cut open the old rad and saw that the inside of the radiator had a light oxide layer and this on other cars can be enough to reduce the cooling ability, on those cars there has been fixes by running a CLR mix and then doing a good flush and some nice new coolant

You did a lot of things! Your might try the following:
- remove the thermostat completely.
- check the visco cuppling in hot condition with a „rolled“ newspaper.

And maybe afterwards:
- Flush/clean the cooling system with citric acid
- Cut open the old radiator and check if it was ok. I do not know what new radiator you installed, but it happens that a new aftermarket radiator is not a good as it should be.

When you start your cold car, with hood open and the inside heater on, how is the temperature build up?
What hoses do get warm/hot when?

I would expect:
1) Insider heater circuit
2) After some time the main radiator

I did have overheating issues with another car and in the end a new radiator solved the problem although the old one was flushed and looked ok from every visible angle.

wrote:

You did a lot of things! Your might try the following:
- remove the thermostat completely.
 

It's not a good idea to run without a thermostat as a long term solution, the engine will take longer to warm up, consume more fuel, emit more pollutants, and last, but by no means least, wear faster.

good morning! I'm new to the team, I read your problem and would like to know if a solution was found. I'm having the same problem right after the conversion