All you need for the head job
Head gaskets
Valve cover gaskets
I did not bother to replace the rest of the million gaskets that came with it.

Don't take the exhaust manifolds off of the Y pipe. No need.

You need a 5/8" black impact socket for the head bolts.
And a torque wrench with a good torque scale.

And for me =
40+ hours. As I went slow and worked in the dark sometimes with a trouble light.
Did it outside in the parking lot.

Flickr: Landroverdude2's Photostream

 

jfall -

When I decide to do the head gasket, I am letting a mechanic do it. I could probably do it but I want the peace of mind to know it's been done right and the mechanic I have now found would be the guy to do it! He's been building engines for 30 years and knows his stuff.

As for my cooling fan being on all the time, it looks to be the fan cluth. After sitting all night and morning I checked the fan before starting it. It had resistance for part of the rotation and then it has very little resistance. Continuing to turn it met with resistance again and then at the one certain spot there was none. Then after starting it, there was no "roar" and we have gone from -23c for highs to -2c when I started it so it should have given me that "roar"!

Cheers!

 

Please think for yourself before throwing parts at this problem!I'm a little shocked at the number of people in here telling you EXACTLY what the problem is and that you MUST replace radiator, MUST replace this, that, etc.

Slow down a second and read up on the cooling system in the DII and what makes it unique - especially at idle.This doesn't apply to the clutch fan but does directly apply to the aux fan kicking on at idle in cold temperatures which some mentioned in here.

In very cold temperatures at idle, out Discos are in "bypass" mode, ie. most coolant goes through heater core only. In this state, the "sensing holes" in the tstat allow a small flow of coolant through the radiator and onto tstat sensing area, so it still knows when to open up. In very cold temperatures, this flow from the radiator is so cold by the time it hits the tstat sensing area, that it causes the tstat to close further and increase temps. It is very counter-intuitive that cold temps increase engine temps, but makes perfect sense when you study the system!

The RAVE manual SPECIFICALLY STATES that engine coolant temperatures can increase by as much as 50 degrees in cold temperatures. Once moving, the increased flow sends a more accurate temp to the tstat and this isn't noticed really, but it's dramatic at idle. The trigger points for the aux fan are well within that 50 deg range of cold temperatures (honestly even a 15-20 deg rise at idle would be enough to turn it on, but I forget what the exact trigger point is).

There isn't any way around this with the bypass system. The new motorrad tstat has 2x large sensing holes instead of 4x small holes on the OE unit - I have yet to verify if there is a flow increase at idle which makes it more accurate.

 

Do members with scanner or Ultra Gauge confirm this in cold weather? I can see the thought path here, but it would be good for members that have instruments (beyond the factory gauge) and cold climate to note their experiences. If it does work exactly this way, with a 50 degree swing, that could have been one reason Rover made the heat gauge work in such a broad fashion. I guess this would only happen at idle, not fast idle, etc. No good deed goes unpunished, and the flip side is that when you are running 40F hotter than normal for months at a time the D2 factory gauge will let you think everything is fine.

If engine is raised above idle (like ECU making it idle faster in cold weather) the soft spring part of the stat allows that sample disk to descend, and increases flow thru the mixing chamber, out the slots in the bottom of the double wall housing, and off to the water pump and the heater core where it is needed. This flow brings the stat up to temp, but the increased cold water from radiator closes it down again. Not like a light switch, because it is still a ball of wax inside the stat that has to melt and re-harden.

The holes are part of a delicate balance. We have had members report overheating problems with the holes clogged (Dexcool, ordinary sludge, rad flushing, and coolant stopz leakz).

We have had members who used the remote conventional thermostat mod and too many or too large a hole drilled in the stat get ECU codes for a stuck open stat, triggered by the radiator temperature sensor. Have not heard of members with new 180 soft spring stats having this issue. I suppose if you went about drilling your own holes in the metering disk it might happen. Larger hole less likely to become blocked I suppose.

It seems like guys in the frozen north might end up with a "winter" piece of cardboard blocking some (not all) of the radiator. Sorta like the semi trucks do.

 

EstorilM - My new mechanic that I have been recently talking to said a lot of the same as what you have mentioned here. As it turns out, it is my viscous / fan clutch that is not operating properly.

I know that before my fan clutch stopped operating properly that my cooling fan did run fairly often in warmer weather even with a new t-stat, water pump, belt, etc. but it never ran this often in the really cold weather.

I am waiting for a new fan clutch and once that has been replaced I will update how the vehicle is running.

Savannah Buzz - When I first got my Disco, three winters ago, I tried a small piece of cardboard on the front of the grill but I had to take it off as I noticed the temp gauge climbing slightly and that was even when it was very cold out up here in Edmonton, Alberta Canada. With a wide open grill the temp gauge does not go up, or down in the cold, it stays right in the middle. Like any car the air blowing is not as hot in the frigid cold, but it's still warm air blowing!

 

Also, since everything is closed at the moment, does anyone know if there is a difference between a fan clutch for a 4.6l V8 and one for a TD5 Diesel engine?

 

An alternative is one for a 2000 Chevy express van, 4.3 liter, without AC. And gauge will show 50% from about 150 to 240F, a scanner or Ultra Gauge gives a more accurate picture.

 

I have had a scangauge in my dad's d2 for years, and i have never noticed any big swings in temperature from winter to the warmer months. It runs 193-198 when on the move, and usually 198-204 idle. Winter or summer.

I have noticed though, in winter the t-stat sometimes lags slightly to open. Not dramatically, but enough that the truck hits 204-206 and stays there for a bit. Then eventually the t-stat opens and cools things down.

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No idea about td5/v8 fan clutch compatibility, but i have had good luck with the "Hayden" brand clutch sold for the D2.

 

Savanah,

The fan for the Chevy Express van you mentioned, is it an exact fit for a 2004 Disco with the 4.6l engine? The fan clutch changed for 2003 / 04 compared to the earlier models did it not?

Thanks!

 

The biggest change was that the earlier DII fans would unbolt from the the clutch whereas the 03-04 fan and clutch were a one piece unit. (the shape of the blades changed too) but you can bolt an early clutch and fan to the 03-04 pump flange.