You've changed most everything except the radiator. Before you do that why don't you try a simple flush? A real good flush? Including the block, radiator and heater core.
One interesting test you can try is to crank the heater on hot and the fan on high. See if you get really hot heat out of it. If you don't that could be a clue as to crap throughout your system.
After that I like to disconnect the two heater hoses at the thermostat. First flush thropugh the long hose. Then flush through the short hose. Keep an eye on the crap that comes out, if it's really nasty go a step further and flush the block.
When I see the heater core pumping a bunch of crap out I always decide on a couple hour job of removing the radiator and really flushing it both ways. When the guy installed your radiator in 2005 he may not have flushed the crap out that was causing the problem.
Flush your engine block (they make that flush stuff) when the radiator is out.
Check your bottom radiator hose, you should be able to feel a spring in there when you squeeze it. In fact check that first I you haven't. If there is no spring the hose will collapse. Maybe the guy put the wrong hose on when he put the new radiator on.
Check back with us...
Mike

 

180 deg thermostat is the way to go only if you have dual electric fan conversion.

 

Bad tech. The PCM needs to see 195Deg. F in order to switch from open loop to closed loop.

 

Sorry, I misread it.

 

It depends, on all the Renix models sold in Europe there is no cat and no O2 sensor, it never comes to closed loop operation. A 180 deg thermostat doesn't necessary mean the engine runs at 180, the highest operating temp is determined by the heat exchange capacity of the rad+fan system. I get 210 at idle and 190 at cruise speed.
In my case since i have a propane system the engine runs in open loop mode anyway.

 

The OP has a 93. Renix spec's don't apply here.

 

That was just an example, like i said, a 180 deg thermostat is recommended only on a dual elecrtric fan conversion, since you don't have a mechanical fan turning that slows down the heat increment at warmup mode. That's what we were talking about, and that you feebly confuted with no technical input.

 

Throwing out Renix spec's as an example in a thread regarding an OBD1 rig isn't going to help a newb.

You as a moderator should be more aware of how much damage bad, misleading, or confusing advice can do.

 

[quote: you don't have a mechanical fan turning that slows down the heat increment at warmup mode. [/quote]

Huh?

 

I am not a moderator. No damage or misleading advice here, only replying to you.

 

Huh?[/quote]
what's wrong with that?

 

If you are concerned and want to replace the fan clutch get the one for a ZJ which is larger and puts the fan a tad closer to the radiator. But it operates a lot more than the stock fan clutch.

 

what's wrong with that?[/quote]

That phrase I was referring to is very confusing. The syntax is strange. Do you mean that with no mechanical fan, the warmup time to full system stabilization takes a longer or shorter amount of time?

 

Fanatic is from Italy so his english is a little different than ours at times. I believe he was saying that if someone has a dual electric fan conversion that the system will warm up faster since the electrical fans wouldn't be running when warming up like a mechanical fan would be...

Hopefully I interpreted that correctly...
Mike

 

i would lean toward insufficient airflow, imo. it should warm up a little when you stop, but it sounds like its warming up too much and too fast. what does you fan setup look like? but a coolant flush is aways a good idea, just to keep things working properly. btw i would also stick with the 192-195 degree thermostat.