I'm about to do a round of preventative maintenance and this is on the top of my list. My bleeder already cracked (caught it within 60 seconds, luckily I was on a gravel driveway and smelled coolant!) replaced it with a metal tee w/ metal plug.

Now I'm starting to smell coolant again (though after the bleeder blow out mess that doesn't surprise me!)

There's a trace of some dried coolant around the upper housing. What are peoples symptoms for these things? I see a lot of write-ups but I'm trying to get a feel for how they fail.

Next question is should I do the upper or entire thing? Upper looks like a 45 min job, entire thing looks like maybe 2 hours minimum and a LOT more bleeding woes (I seriously hate bleeding these 4.4s, I didn't think anything would be worse than my DII!)

I should probably jump on it ASAP considering it's going to be mid-90s for the next 7-10 days it looks like, and I usually sit in traffic for over an hour every day.

edit: just read that the superseded upper thermostat housing part doesn't fit the 05-06 4.4 engine lower housing? So I'd have to find a P/N for the OLD upper or just replace the entire thing.

What did they update on the 07+ units anyways?

 

This is the thermostat housing for the 2005 LR3, which parts are you thinking of changing? Of course you could just get the seals. As you can see from this micro-cat extract the main body is not shown as available on its own and the complete unit is $119.95 from Atlantic British or individual seals are between $4.60 - $9.30 on Amazon.



The table below gives the part Nos.

 

I just did this job for the very same reasons: whiffs of coolant around the grill (after replacing the bleeder and the expansion tank) and traces of coolant on the front of the engine.

I replaced the entire assembly as a single unit in about 2.5 hours. Most of that time was spent gaining access.

Once I removed it I saw the issue - the entire underside of the upper section (thermostat housing itself) had been slowly leaking coolant out past the seal for quite a while.

Now there's no more coolant smell and I finally know why I had to top off the coolant every three weeks or so.

 

Plastic parts with high heat.......Do the whole thing and the thermostat so you don't have to go back.

 

Entire assembly for sure.. Genuine is my preference.

 

Do the whole assembly. The simple reason for it is not just aging plastic, the new upper housing won't fit the old lower part ,that is bolted to a manifold.I find out about it while changing mine some time a go.

 

I just had to fit a new lower housing on my '05 LR3 and had no difficulties with fitting old to new. As for the upper housing it was in perfect condition and after fitting new seals, have had no problems.

Never-the-less there are a couple of other advantages to buying the complete unit i.e. it comes complete with new temp. sensor and thermostat.

 

Yeah I thought about it for about 5 minutes and decided to do the entire thing. Granted I'm sure there are specific reasons the top fails first, due to design or temperatures or tstat location or whatever - but after the bleeder tee failing I'm all about replacing as much of the high-temp plastic parts as I can. If the top is failing, I'm sure the lower unit is structurally compromised as well after 10 years.

I'll sleep better at night anyways - I got the thing last september (3rd used rover though) and it's really been very good to me. Stupid stuff like tailgate latch and leaking cowl, but that's really it. I've put almost 14k miles on it since last September and it's going to hit 100k miles in the next two weeks I think. Anyways it's not like I've spent an arm and a leg on her yet, so I'll gladly shell out some insurance on something I KNOW will cause me problems later on.

Plus if there's one thing I've learned about keeping rovers on the road, it's to never cheap out (if anything, go overboard) on anything cooling-related!

 

The top thermostat cover on our LR3 is leaking. I was concerned about the "new" design not fitting the old lower housing. I called the dealer and they told me that they sell them all of the time without any issues. They said that they do not show any upgraded parts that won't fit the original design. The price was shocking.....over $100 for the cover and another $7 for the o-ring. Atlantic British only sells the entire assembly, $115 and BP Utah sells the cover for about $50, around $60 on ebay with the 0=ring included. I plan on swapping out the cover and o-ring only for the time being. I don't have a vacuum to properly suck out and replace the coolant and I can't spend three hours on it right now and my wife wants her car back......happy mother's day! Please let me know if there is something I have missed on just replacing the thermostat cover. thanks Phil

 

x2 on doing the whole bit. Get the genuine part. Don't be afraid of bleeding, it is easier than they say it is, and you will be surprised by how much gunk gets in those plastic pieces.