Diagnosing cooling issue
#1
Diagnosing cooling issue
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
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
#2
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.
#3
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
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
#4
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.
Then after that monitor your temps and report back.
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jasonstaczek (05-19-2016)
#6
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.
Category
2. At 60 mph, transmission in 3rd, tach at 3000 rpm, ECU reports 206 F.
radiator or the fan clutch, or both
I can pull in the driveway at a temp over 212, shut the engine off and not get the fan.
Electric cooling fan switching points:
For A/C system:
⇒ On When vehicle speed is 50 mph (80 km/h) or less and ambient
temperature is 28 °C (82 °F) or more
⇒ Off When vehicle speed increases to (62.5 mph (100 km/h) or ambient
temperature decreases to 25 °C (77 °F)
For engine cooling during normal running:
⇒ On 100 °C (212 °F)
⇒ Off 94.5 °C (202 °F)
For engine cooling at ignition off (to counteract heat
soak):
⇒ On If, within 10 seconds of ignition off, intake air temperature is 60 °C (140
°F) or more and engine coolant temperature is 110 °C (230 °F) or more
⇒ Off After 10 minutes or if engine coolant temperature decreases to 100 °C
(212 °F)
For A/C system:
⇒ On When vehicle speed is 50 mph (80 km/h) or less and ambient
temperature is 28 °C (82 °F) or more
⇒ Off When vehicle speed increases to (62.5 mph (100 km/h) or ambient
temperature decreases to 25 °C (77 °F)
For engine cooling during normal running:
⇒ On 100 °C (212 °F)
⇒ Off 94.5 °C (202 °F)
For engine cooling at ignition off (to counteract heat
soak):
⇒ On If, within 10 seconds of ignition off, intake air temperature is 60 °C (140
°F) or more and engine coolant temperature is 110 °C (230 °F) or more
⇒ Off After 10 minutes or if engine coolant temperature decreases to 100 °C
(212 °F)
......
Last edited by number9; 05-19-2016 at 04:45 PM.
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jasonstaczek (05-19-2016)
#7
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
THERMOSTAT ASSY DII & FREELANDER 180 DEGREES FAHRENHEIT, PEL500110, RNQ028 - Rovers North - Classic Land Rover Parts
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jasonstaczek (05-19-2016)
#8
#9
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jasonstaczek (05-19-2016)
#10
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.
Last edited by chubbs878; 05-20-2016 at 12:16 AM.