I've been smelling some coolant burning and opened up the hood today. No coolant making it to the floor; I assume burning off on the engine. I found some pooling on the engine just below the thermostat, as seen in attached picture. Without removing throttle body, etc..I can't confirm exactly where the fluid is coming from. My first guess would be the thermostat housing. Wondering, given the location of the coolant U seeing if that's the most likely cause or is there other possibilities in that location and what might be the easiest way to locate the root cause of the leak. ***It's definitely not a crumbling bleeder valve up top as that's already been converted to brass. Any ideas?

 

The thermostat housings on these are basically a maintenance item. The develop cracks and leaks

 

Yup....just changed the thermostat on both the '05 and the '06. Not sure about the '06 but on the '05 it was replaced in 2014 previously.

 

Yeah..I paid a shop to replace the housing on our 2006 and I'm embarassed by how much they charged me! So, if I can diagnose it I think I'll give it a whirl myself this time. On my way to borrow a pressure tester. Thanks.

 

When I swapped out my entire Thermostat housing assembly last year sometime, I seem to recall that I had difficulty getting to 1or 2 of the Torx Bolts. I had to use a long Torx driver with T-shaped end, to be able to get enough downward force and torque onto the Torx Bolt head, in order to remove. Almost stripped 1 or 2 of the bolt heads, prior to using this tool. I therefore decided to replace the old Torx Bolts with stainless steel Hex Head Bolts, when I swapped out the housing.

I think I may have been lucky - Original Thermostat and Housing lasted about 180,000 miles.

Yes, I agree, in future I will consider this swap to be 'preventative maintenance'. If I can find an additional lower mileage 2008 LR3, in great condition, locally...

 

I got a loaner pressure tester and put it on the system. Pretty much held pressure, so this leak is pretty small at this point, which is good news. But, upon inspection I'm not seeing any coolant escaping the thermostat housing, at least the parts or connections to the cylinder heads that I can see. That said, the coolant in my picture is on and just behind the water pump and now I'm thinking this is more likely a small leak through the water pump gasket.

I've read that in many cases the water pump gasket will wear out before the pump itself. On first blush, it looks like a water pump swap out is a bit less complex that the thermostat housing.

Any other comments or advice that may help are definitely appreciated.

 

It could be the housing or it could be the hose off the back of the water pump, another known point of leaks. This hose is actually the one that runs up to the t-fitting that fails. I dont think the pump will leak to the back because the way it mounts, it mounts to the face of the block so that would mean the coolant would have to leak up over the top and back.

This pic I stole from the net, but it shows the hose that can leak.



By the book replacement requires intake removal. But if you have a curved long nose pliers you can do it much easier. Even a regular nice long needle nose will work. Basically you remove the coolant cross-over assembly. Once that is out of the way you go into the very narrow space and work the hose clamp back off far enough so slide the hose itself off with a nice large flat-head screwdriver (carefully). With it released you just work it out to the left.

The new one you will have to attach two strong strings. You will also have to loosely secure a worm-type hose clam to it. Not too tight or it will not slid onto the nipple. Lubricate the hose with coolant or something that will break down over time. But you want something to aid it slipping it on. Work the large hose end in via the right side. So basically carefully push the skinny part of the hose between and behind the nipple with the large section to the right then once in you pull the hose into place from the left. Work it into position and pull the two strings evenly to get the hose to slide onto the nipple. Carefully tighten down hose clamp, no too much to cut the hose. Then I generally bend back the "tail" of the worm clamp to prevent it from working loose.