Hi guys,
I have swapped a range rover classic, having now l92 with ls3 intake manifold, 6l80e, running great, still not tuned yet ( only initial tune to make it run )
I had some problems with overheating, i have removed the thermostat and bled the system two days ago, and since then, car is running on good temps ( goes up to 203 and down to 192 - that's where the fans shut off ).
So far so good, but taking it for a spin on highways can raise the temp, around to 215/217, then if I go in a slower speed or even park it, it decreases to 192 again.

Radiator is new, 2 mishimoto race line fans, new water pump ( acdelco ), fans pull great when standing they are very powerful and can reduce temps and shut off in about a minute, antifreeze only.

What can that be? a bad tune ? ( I see A/F Ratio around 15.0 on highways - on the dummy obd reader )
I can run it for hours in town and everything can be perfect, even with A/C on.

Any ideas ?

Thank you!

 

Sounds like you need a larger radiator if it cools all other times.
If it gets too warm when running harder than otherwise, you need more cooling capacity.

 

i can cool it if i run the fans manually, but that is super weird because the air flow of a moving car is way higher than two fans, thats why im starting to think im running lean

 

If it cools only with the fans on at highway speed, you might have an airflow issue that the fans are "band-aiding".

 

What do the spark plugs look like? Pull a few and have a looksey. Plugs don’t lie, but 15.0 on the interstate is lean, if it’s right. Trust your spark plugs.

 

I will take a few spark plugs later today.
I tried blowing air with air blower from the grill and feel the air moving in the back of the radiator, no luck, looks like something is blocked there, I just sorted my AC, looks like i'm going to remove it again.