So, after blowing the head gaskets on my 99 Disco I I've been super careful with my 02 Disco II. As soon as I got it I drained the Dexcool and replaced it with Prestone checked all the hoses and watch the scangauge like a hawk. The other day while I was on a 1000 mile road trip I noticed while I was sitting still the temperature started rising. While I was on the highway it almost always sat at 194 degrees. When I came to a stop it would go up to about 210 and never past that. So, when I got back I changed out the fan clutch due to the fact that it was fairly easy to spin. I checked it against my gf's disco I fan clutch and hers was fairly stiff. I went with the fan clutch imperial extreme duty #215158 listed somewhere else on this site and it is still behaving the same way. The fan is still easy to turn and the temperature is still within the same range and there is no "fan roar" described by other users of the severe duty clutches. Do you think that I just got a bad fan clutch? What could be some other culprits?

 

If still easy to turn it is bad. Should be stiff enough cold to spin, release, and blades travel on part of a revolution, free wheeling means no fluid inside or bad valve. Until you have a good fan clutch running warm will continue when stopped or slow. You are not fried, but who wants to to be hot this time of year.

You could also have fan bolted on reversed on some trucks (cupped side of blade goes toward block), you electric fan should be coming on, the radiator could be sludged from original Dexcool (will be colder on bottom rows of fins), your radiator and consenser could have leaves and mud blocking the fins.

 

Thanks Savannah, you're always a big help. I'll check the different levels of the radiator for temps as you suggested. There's definitely no mud or leaves blocking anything and the fan is on the right way. I double checked before I put it on. Sounds like I put on a bad fan clutch as I suspected.

 

Did you let the new fan clutch sit vertical for 24 hours before installing?
If not you may have ruined it, I learned that the hard way.
If the fan clutch sits horizontal for to long all of the fluid inside it will settle in the clutch, like pudding in a pie pan.
It needs to sit vertical (just like when installed) for 24 hours to allow all of the fluid to settle back to the bottom, if not when you start the engine you can ruin it.
Trade it for a new one, let it sit for the 24 hours, then install it, or install it but do not start the engine or spin the fan fast.

 

No I did not. Dang it, I read up on it and didn't see that information. I'll trade it in and go from there. Thanks Spike.

 

How about your t/stat, did you replace it when doing the head gaskets?

 

Hey Mike, I never changed the head gaskets but I did change the thermostat.

 

Fan clutch needs HEAT to activate the bi-metalic thermo spring which is right on the front of it and produce clamping friction which spins the fan.

If your radiator is PLUGGED with crud on the outside - then no air with heat will reach the fan clutch.

If your radiator is plugged on the inside - no heat will reach the fins.
fan clutch will not engage without heat.

Try a hairdryer on high.
Blow it on the fan clutch for 5 mins.
If it is then harder to turn, then the test confirms the fan clutch is at least responding to temperature correctly.

 

All true, but fan clutch also has to have fluid inside to produce the reaction, and normally parked for a few hours that fluid will pool to the bottom, causing short term lock up when cold (the roar at start up). If it spins free when cold it is unlikely to work properly. Normally coupling is reduced to 20% when fan is "normal" and increases to 70% or more when fan is hot (like 170F on faceplate). But it should not be zero %.

 

Well, once I pulled it all apart again (much easier the second time). I realized the water pump was leaking through the weep hole so I went ahead and replaced that. Almost had it all back together and it started pouring rain... So, I'll finish it tomorrow! Got the new fan clutch too and its sitting vertical as we speak. I watched them pull it off the shelf and they stored them vertical too, so that's good to know.