Replaced coolant housing and hoses for a leaking coolant system, flushed too. doesn't leak anymore.

However was running it today. When driving ranges from 195-206F, when idle about 202-212 (at it's highest).

What should the optimal temperature be? How do I cool it down? any tricks?

180 degree thermo will help?

 

If that is a stock temp thermostat = normal temp range. 180F will usually be 184-204F, and these trucks will start to run hot at idle regardless. Very small grill opening, and not what I'd call a large radiator.

 

180F thermostat doesn't really change the overall max engine temp. It just allows it to reach it much much more slowly by opening sooner to allow the coolant to flow quicker vs build up temp. However eventually like at idle or under load the engine will heat up.

These puppies were running 210, 215, to 225F all day long back in the day before OBD2 gauges like an Ultra Gauge or Scan Gauge II. That is not good for keeping a D2 happy so that's why people use the 180F thermostat, or inline 180F mod, a HD fan clutch, and green coolant.

I don't sit at idle for long. I'll let me D2's get up to 210-215F max, but after that I either get moving or shut it down. Out on the trail I use a lower gear and keep the RPM's up around 2400/2600 and that lets the HD fan clutch engage and my temps can go from 206-209F out on the trail to 188F quickly.

 

Thanks! It's OEM original.
I might invest in a 180F degree thermo just to be safe.

 

Better option is to send a PM to Extinct to get one of his inline thermostat mods. Much cheaper and easier than dealing with the strange OEM configuration.

 

I'll consider it

you running this?

 

Yes. A number of us are. With a 180F thermostat installed (you can put in whatever temperature you want) I am now usually running around 177F, sometimes rising up to near 190F if I'm really pushing the engine. I haven't had it installed during warm weather but I doubt that will make too much of a difference.

 

I replaced the thermostat, the fan and the radiator, but with months in between. Every step reduced the coolant temps a bit. The thermostat made the biggest impact, the fan made a big impact when idling (viscous coupling was worn on the old fan).

I have a 2004 where Land Rover cost-optimized the oil cooler away. I added an oil cooler and that helps to run cooler too. Pls note that the oil gets way hotter than the coolant. The coolant temps alone do not give you the full picture. I found that out after installing an oil temp gauge.

 

^^this.
i have two (2) '04s.

a PO added the oil cooler to the one that i drive. even with the 2" lift and larger tires it runs cooler than my stock '04 with the thermostat mod.

both trucks have newer water pumps, radiators and fan clutches and both run on the green coolant.

 

Do Extinct’s inline mod, it’s very easy, comes with instructions, and basically the same cost as a new genuine 180 thermostat just by itself.