Hello All,
New Member here, and I love the wealth of knowledge this forum brings to those in need. I have an '05 LR3, which just recently decided to leave little puddles of orange in my driveway. Since I hate dealerships and their prices, I decided to tackle this one on my own.

This is for the 4.4L V8:
Symptoms: messy skid plates; orange coloured residue on front of engine (this actually helps you identify where the leak is coming from since it leaves quite a trail); puddle of coolant when parked.

Diagnosis: Cracked (desintegrating) thermostat housing.

Tools:
Phillips screwdriver
Flat head screwdriver
10mm socket and ratchet
Ratchet extensions
Torx T30 socket
Pliers to release hose clamps

I am not going to get into how to drain some or all of your coolant. You can make that choice yourself. I only drained the top portion of the coolant system so I could do the work with out interference.

OK, here we go:

1) Use the phillips screwdriver and undo the 7 screws securing the airfilter box.
2) Unclip the MAF sensor connection.
3) Loosen the jubilee clamp connecting the air tube to the throttle body.
4) Disconnect the crankcase vent tube from the air tube.
5) Remove air tube from throttle body, and place entire airbox cover-MAF-air tube group out of the way.
6) Remove top fan shoud. There are clips holding this to the lower portion. Just pull.
7) Disconnect all hoses going the themostat housing, and coolant temp senson connection.
8) Using 10mm socket, remove the 2 bolts connecting the secondary air valve to the throttle body assembly.
9) Undo the electrical connection to the thottle body.
10) Using 10mm socket and extentions, remove the 4 bolts connecting the throttle body assembly to the intake manifold. (these are the 4 bolts holding the entire TB assembly to the engine, not just the TB itself. You can separate the TB from the assemble using its own 4 bolts if you want to clean the TB while there.)
11) With the TB assembly up and out of the way, you can locate the first 4 Torx 30 bolts holding the Thermostat housing to the block. Remove.
12) Remove the other 4 T30 bolts holding the Thermostat housing to the block. (2 on left side, and 2 on right side, on front of engine) The lower bolts are hard to see, but with an extention, and your fingers to guide the T30 socket, this can be done.
13) Remove Thermostat housing.

The new Thermostat housing I purchased came with all seals, Temp sensor and Thermostat already installed, so now its just the reverse procedure to reinstall.

I do not have th specs for tourque values on the bolts removed, but I just tightened them to snug (tight, but not stupid tight).

Once all is back in place (don't forget about all your electrical connections: MAF, TB, Temp sensor), follow standard coolant bleeding procedures, which can be found online. Be patient, it took about an hour for the bleeding to be completed.

Hope this helps anyone staring this job down.

Regards,
Andrew

 

Firstly, let me thank you Hawk99 for your detailed post. It certainly took a lot of guess work out of this job.

I can not emphasize enough how important it is to have the right tools. I definitely would add swirl head and 10" ratchet extension to the tools list. The lower right screw that holds the entire Throttle body assembly to the engine block was very tricky for me. It took me a good half a day to unscrew it because I didn't have the right tool. I put everything on hold and went to bed. The next day I headed to Harbor freight bought the 10" ratchet extension and swirl head. Only 5 seconds to put back and tighten the same screw that gave me so much trouble the previous day.

Also I made a mess trying to capture the coolant from the top hose. Avoid doing that and try to drain from bottom. Enough that you won't spill when you are disconnecting all the hoses during the thermostat housing disassemble.

I've attached a picture of the thermostat housing to show the hairline crack. I was not loosing to much coolant but from time to time I would see few drops of coolant on the garage floor and decided to tackle the job and replace it. Bought the entire thermostat housing (has the thermostat and all the seals) on ebay from Land Rover dealership for $110.

 

Good write up. I just want to add that you did the right thing. Many people replace just the thermostat end (including the dealer), however I highly recommend the whole assembly, as they are also prone to leakage.

 

NOOB question, before I tackle this. What is a swirl head?

Is this the same thing as just a regular ratcheting socket driver?

or some kind of flexible end to change the angle? (while using the 10" extender?)

 

I will be doing this process soon and I found the steps on this forum very handy but I also found another reference to same procedure (LR3) with pictures that will be handy to have so I decided to added here to help others on the same boat.

Reference
LR3 thermostat housing replacement - Defender Source

Enjoy Roberto

 

Added link to tech section

 

Can I install the front half of the housing assembly and not the top part so that no intake (OR throttle body and EGR) removal is necessary?

 

Um.... the intake does not come off for the thermostat housing anyway.

 

|I added "either the intake Or the throttle body and EGR. Thanks for the fast response

 

The throttle body/plenum and EGR are very easy to remove and necessary to to the thermostat housing. The EGR, for example, can have just two bolts removed from the pipe since the EGR itself can remain attached to the plenum which is coming out. And I think the plenum and throttle body can be take out as an entire unit. So you are looking at 6 bolts, about, to get that stuff out of the way. The worst part is the plenum bolts, have to get creative with a couple using extensions and such.