Hello All!

I have an '03 Discovery II that seems to have a couple bugs in the cooling system. It has new top hoses and tee and a new stock thermostat. It seems to be running hotter than I'd expect. For example:

1. At 60 mph, transmission in Drive, tach at 2000 rpm the temp reported by the ECU via an OBD II device is 217 F.

2. At 60 mph, transmission in 3rd, tach at 3000 rpm, ECU reports 206 F.

So higher RPMs, but same forward speed and ambient temp, and I get a lower coolant temp.

Now I'm scratching my head trying to understand whether that could be the radiator or the fan clutch, or both.

Also, the auxiliary fan never seems to come on. I can pull in the driveway at a temp over 212, shut the engine off and not get the fan. I thought it was supposed to come on anytime the engine temp was over 212, vehicle running or not?

Thanks for helping me think through this. I don't want to start throwing parts at it just yet. I'd like to try to understand what it's doing!

Best,

- Jason

 

You need to put in a Genuine LR grey 180* thermostat for starters. Then monitor temps. And yes your auxiliary fan should be on at 212*. The fan should also work when AC is on and outside ambient temp is around 80*. I don't think it needs to be 80 for the fan to run though, mine seems to run at a lower temp.

 

Thanks, Motorhead. This is the thermostat I put in:

Thermostat Discovery Series II (Part # PEM100990)

Is that the one you're talking about? If not, where's the best place to get the good one?!

Thanks,

- Jason

 

Get an OEM 180F Thermostat, then grab yourself a 99-02 Fan Blade and either the Hayden 2991 fan clutch or comparable unit (your 03/04 is a one piece unit). On the efan, test it with power directly to it or just jump the relay and see if it powers up. Also check for any blown fuses.

Then after that monitor your temps and report back.

 

welcome. some good advice so far. also make sure to search earlier threads, lots of good solutions already out there.

 

Mine's about 188F at same speed. Suggest you get new 180 F thermostat. Many say go with the LR gray soft spring but linked one's working fine for me.
Category

Water pump may be suspect.

Generally fan/clutch issue will cause higher temp at idle.

Fan should come on when AC on or coolant very hot upon shutdown.

Your current temps are to0 high and may want to start with drain flush of system, the thermostat and possibly a water pump.
......

 

Here's the t-stat you want. You can buy it through Lucky8 I believe too.

THERMOSTAT ASSY DII & FREELANDER 180 DEGREES FAHRENHEIT, PEL500110, RNQ028 - Rovers North - Classic Land Rover Parts

 

Wow! Thanks, everyone, for the ideas and quick replies. Got some parts ordered. Going to to try the flush/tstat/water pump first and see if anything changes.

Your help is much appreciated!

- Jason

 

You need to bleed it first. Don't start throwing parts at it until you change the stat and then bleed it.


You can use the method in the book, or imo what's better is parking on a steep hill.

 

I also own a 2003 that I got exactly 1 year ago and within the first month every single piece and part of the cooling system broke/faulted or was on its way out. I mean even the plastic lines. Replace EVERYTHING and refill it with the green ethylene-type antifreeze, distilled water, and a whole serving of coolant additive (it works.) Even all of the small rubber hose connecting the plastic lines at the radiator/tank/manifold needs to be updated with new hose and run it directly to point-B where the factory plastic pipes went. Those 210+ temps with DexCool corroded everything from the inside. The AC fan will do nothing for your operating temps but it needs to be in working order nonetheless. Having been there and done that, just update everything on the coolant system because it's all **** from the inside, out.