Hello all! I’ve got a 2001 Disco 2, yesterday drove to Southern California in 115 degree heat. I’m planning on getting a ScanGauge to monitor engine temps, but it seems like my radiator fan never turned on yesterday. I had the AC running and I know that fan works, but when I got to the house the engine felt super super hot. Of course the interior temp gauge stayed at normal reading the entire time. If anyone knows a little more about this, I’d love to hear. Thanks!

 

Engine will always feel super hot - even in ideal operating temps, the coolant is around 190F. Maybe some people could, but I doubt I could tell the difference by touch between a truck running at 190 and one running at 220.

There are two fans in front of the engine - the engine cooling fan is driven by the engine itself and is behind the rad - it mounts to the water pump and is always spinning when the engine is running (it's beneath the curved plastic piece in front of the engine). In between the AC condenser and the grill, there's the condenser fan, which is electric and should kick on in the following conditions:
1. AC on
2. Ambient temperature is > like 80F
3. Speed is <40MPH
OR
1. Coolant temp is > 212F

Often, the condenser fans seize up due to water ingress and need to be replaced. You can test this by standing in front of the truck and trying to use a long screwdriver through the grill to spin the blades - if they don't move freely, then it's likely due for replacement. When you replace it, chances are that all of the fasteners have rusted and will break, so lots of folks just zip tie in a new one. They're pretty expensive to buy new but you should be able to find used ones on eBay. When it seizes, it will pop a fuse under the hood as well, so you'll need another (I think its a 40) but it's on the diagram.

My condenser fan is currently seized and unless I'm idling for an extended period in hot weather with the AC on, it doesn't impact my temps. Especially in a warm climate, the condenser fan will make more of a difference, but really only if you're sitting around idling with the AC on.

If you're looking to get your temps down, there are other areas that will have a much more substantial impact:
1. Thermostat - get a 180F
2. Clogged radiator
3. Fan and heavy duty fan clutch

 

Forget the factory 180 thermostat, do the inline mod. Much better results. Do a search, couple different options to do it, but the best mod ever for a disco, 2nd best is PCV mod.

 

If you pop the hood with the truck idling it will take about 10 seconds to identify if the giant fan in front of the engine is spinning or not.

 

Nicely done!

 

This is very helpful, thank you all! The past few times I have driven it, when i get home and park, tons of coolant is spitting out of the overflow tube on the expansion tank. I have confirmed that the AC condenser fan does work when I turn on the AC, however I am starting to think that the main radiator fan is not working...? We have a brand new thermostat in the truck (190), brand new coolant. All hoses are in good shape and no leaks anywhere.

Im starting to wonder if the fan clutch has gone bad? Even in low temps and high temps outside when driving, I have NEVER heard the main radiator fan turn on. I distinctly know what D2 main fans sound like, and I have never heard it run. Do the fan clutches go bad??

Thank you all again!

 

You need to start with getting an Ultragauge or similar to monitor temps - the gauge on the dash is useless. Coolant coming out of the overflow tube is not good. I'm assuming that you're not overfilling the overflow tank. Has the system been bled properly? How much coolant are you losing? You might consider getting a test kit for exhaust gasses in the coolant to diagnose a failed head gasket. This is much higher priority than a possible bad fan clutch.

Re: Cooling Fans: The main engine cooling fan is not electric - it's bolted to the water pump and spins whenever the engine is running. You won't necessarily hear the stock one, but unless it was removed, it's definitely spinning when the engine is running. You won't hear it turn on and off. It is possible that the fan clutch has gone bad and you're not getting as much rotation of the fan as you should. Next time you drive the truck, after you park it while it's hot, shut it down and turn the engine cooling fan by hand. Assuming you haven't just gotten off of the freeway and there's been some heat buildup in the engine compartment, it should be pretty stiff to turn and you shouldn't be able to get too much rotation. Suggested replacements / upgrades for the cooling fan and fan clutch are the Dorman 620-112 and Hayden 2991. They bolt right on. I'd replace the stat with a 180, too. I used LR OEM 180F (sourced from Lucky8). My temps are 188 on the highway, 188-194 in traffic.

 

Ok. I actually think I did overfill it one day on the way down to the desert. That’s what I’ve first suspected. I haven’t checked to see if the main fan moves even if engine is at idle. I have ordered a ScanGuage 2 to install on the truck. Because of the coolant pouring out, I believe the level is down now so I was going to fill to cold level. But I should check today to see if main fan moves/does not move

 

And you are right about the head gasket possibility, when i bought the truck the owners did not know if it had been done, but I bought the truck at 203K miles, so its had to have been done at least once. I now have almost 207k on it. I dont see any oil deposits in coolant so far.

 

When cold, it should have some resistance. Some people describe it as like you're stirring peanut butter. When hot/heat soaked you shouldn't be able to get more than a turn or two out of it. As long as the fan wasn't removed, I promise that it's spinning when the engine is running.

Overpressurization of the cooling system is likely not tied to the cooling fan unless you're idling for long periods. I think you need to reprioritize this - I wouldn't expect replacing the fan and fan clutch to solve your overpressurization problem. Auto parts stores sell a test kit that will check for exhaust gasses in the coolant. I'd start there just to rule it out, if nothing else.