Changing to an Inline Thermostat on Land Rover Discovery II

Today I install a new thermostat from Inline Thermostat into Cassie's Land Rover Discovery II.
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This Week With Cars - Episode 0344
#landrover #discovery #thermostat

[@ianburit3705]

Hi Steve, that's a great idea and set-up. On my smaller Freelander HSE with its 2 litre BMW diesel and auto box, a modification recommended is using a UK-based kit that fits the Rover 75 diesel with the same BMW 2litre turbo diesel engine but uses a simple inline, infact it fits inside the top hose after the troublesome factory thermostat - It uses a Renault designed inline thermostat I believe. Had one in my Freelander for 4 years so far and the engine temperature gauge just sits in the middle of the reading in hot or cold weather letting the engine run better. Thanks for the video. Ian - UK.

[@gmeyer6657]

Here in AZ..this is money!! I have also changed out all hose connections to Aluminum + overflow tank!! This is a no brainer!

[@stephenricketts7764]

That is a good set up and one less pipe to degrade over time. Also good advice to change the belt. 👍👍

[@onlyme8870]

I am in this project now plus head gasket I had the white smoke out the exhaust. The only task I did differently is my belt I soak in aerospace 303 protectant versus replacing which I use on all my belts and wiper blades. Its helped the longevity bigtime. Plus I am replacing alternator bracket. Found it was broken. Ill do the valve cover gaskets too and maybe relocate the coilpacks.

[@akope]

Fantastic upgrade. New Thermostat housing even has a good air bleed on it! Cooling system seems to be the weak point of the discovery ii, at least the ones I've worked on. Cheers man!

[@ronaldrrootiii6040]

Yeah the original design made no sense regardless of it being plastic period if you think about it they have the thermostat placed after the radiator flow so the water is already going in the radiator now it encounters the thermostat when it's cooled down and that makes no sense. All other systems the hot water from the engine touches the thermostat and then opens to let in the radiator

[@TheGuardian_TM]

I installed this setup on my ‘03 after upgrading the fan clutch (Hayden 2991) & fan (Dorman 620-112), & installing 180 degree OEM tstat. The initial upgrade dropped my idle/running temps to 187/194-204, & the inline keeps idle 178-183, but my highway temps seem to be all over the place. Can go from 189-207+ during a 15 minute drive at 70mph in the Deep South summer heat. Fall seems to be fine. 180 idle, 194 max highway with the 180 tstat. I am going to try the 170 tstat during the summer to see if that puts me in the correct range. There’s a FB thread about QC issues for this product, & manufacturer said they had a 3% failure rate, but many said they went through 3+ before they got a good one.

[@SB-vb8ch]

I'd be a bit concerned about how quickly the new setup will respond to coolant temperature within the top hose as it's a dead head arrangement until the thermostat opens (therefore relies on conduction rather than purging through the hotter coolant). I'm presuming that a small hole has been drilled through the thermostat to allow for a small amount of flow? Similar factory arrangements would either have the bypass route feeding from the engine side of the thermostat or at least a bleed hose which would go back to the header tank to achieve a similar goal. My understanding of why the vast majority of more modern cooling systems use control on the lower hose rather than the upper is to give a more stable temperature control & minimise thermal shock where you have an engine at high temp & a rad full of coolant which is at ambient which gets pulled in as soon as the thermostat opens.

[@jlwilliams]

I was today years old when I learned that Discos come stock with a plastic thermostat and a plastic tee in the upper hose. I get it that this is an expensive British vehicle (meaning that it's designed on the assumption that when it craps out, Milord simply drives one of his other cars while a hireling hauls this one down to the village to have Alf mend it) but this still seems unusually sketchy!

[@ronaldrrootiii6040]

Not only that but the factory thermostat is placed after the radiator so it has to make its decision based on already cooled down water from the radiator and a combination of bypass water instead of making its decision to open the thermostat based on hot engine water directly from the engine and then letting it into the radiator. Even if they didn't make it plastic replacement of the flow makes no sense being after the radiator

[@bobmanzi7712]

Great stuff thanks

[@khaledabdulaziz8089]

Hi dude , thanx for the great job u doing , I’m trying to get the same belt tensioner u replaced but I didn’t catch it , can u pls put the link of that part pls cuz I tried to go to oriely website & still didn’t catch it , take akit in advance 👍

[@jamesscanachi446]

Solid content AND your presentation style is very clear. What brand did you use? Did you have any post-installation issues? Keep up the good work!

[@ronaldrrootiii6040]

There's a website called inline thermostats that makes this kit for super cheap. I've had it for years and it works totally perfect in fact it works so well that you can't use the 180 because you will run into 170 and throw a low temp code in your cats will throw a code so I use the 195 element which is the next one up in that style and now I'm in the 180s all the time even in Arizona

[@paulhall170]

Any time you can replace a plastic part with a metal part is a good time....

[@billendres3115]

Excellent video. Started following your channel when you rescued the D1, huge LR fan. My question on this upgrade is how did you bleed the system? I know you must use the bleed screw on the oem set up to remove the air. Thanks and I'd love to see more Rover videos. 😊

[@ThisWeekWithCars]

It was vacuum filled to eliminate as much air as possible and then cycled a few times to let it self bleed.

[@sikandar223]

Nice

[@rexkars6740]

What an odd setup! But it works! Maybe if you flipped the forward part of the tstat housing, the bleeder would be up?

[@ThisWeekWithCars]

They have a version where the port is up but I chose this one because it is the cleanest closest to the radiator install.

[@ronaldrrootiii6040]

It works so well you don't even need to bleed it. And really it's not odd it's traditional to have a thermostat coming right off the top of the engine to allow water into the radiator. Having the thermostat placed after the radiator like the original makes no sense because the water is cooled down first and then reaches the thermostat so the thermostat has to make its decision to open based on cooled down post radiator water

[@khancross]

Why are these only for Land Rovers available? Are there not universals?

[@parrotraiser6541]

What weird thought process created that factory kludge? The new setup is much more elegant,

[@MrDunky48]

How did you learn to explain things so well and without a whole load of baloney and ums and arrs! ! It’s almost like you are reading from a text book : remarkable.

[@jimringo2569]

Like how you spend plenty of time proactively fixing up your collection but her car has to break to get any attention!

[@fishaussie9112]

🇦🇺👍what we do for daughters

[@TheGramophoneGirl]

Was there any reason they made the original as they did? Or was it just some questionable Land Rover design for no logical reason?

[@emmajacobs5575]

It’s designed as a bypass system so when the engine is first started up, the coolant still circulates but bypasses the radiator, then as it warms up, the thermostat gradually opens to allow some cold coolant to blend with the hot. When it’s up to working temp and fully open, it allows full flow through the radiator. The idea is to prevent hotspots during warm up and stop thermal shock from cold coolant hitting the hot engine.

[@TheGramophoneGirl]

@@emmajacobs5575 but isn't that the same as the much simpler upgrade he did in the video? Why did land rover make it more complex? Or, is the upgrade not as good?

[@emmajacobs5575]

@@TheGramophoneGirl no, it’s not the same as I don’t think you don’t get the gradual hot/cold blending with the upgrade.

[@johna1160]

OEM set up is an absurd combination of convoluted engineering and plastic parts not fit for any cooling system let alone on a vehicle meant to traverse jungles and deserts. IMO, LR owners are more concerned with the perceived status and cache of the marque than reliability. Otherwise, they'd be driving Land Cruisers!

[@gmeyer6657]

On my second plastic thermostat.. I have changed all plastic junctions. This makes sense here in AZ. I am trying to bullet proof my 04 Land Rover DiscoveryII HSE. Have a tight motor ..thank goodness.

[@ronaldrrootiii6040]

Yeah the original is so stupid if you think about the placement of the thermostat being Downstream of the radiator. Why in the world make the thermostat in counter already cooled down water mixed with a combination of hot water when it should just encounter hot water directly out of the engine. So the inline isn't just better because it's metal and doesn't have a huge bypass it's better because the water straight out of the engine hits the thermostat. That's how all other designs usually work including the Rover before they made this one. Just like an old Chevy engine design hot water comes out of the engine it touches the thermostat it gets let into the radiator makes perfect sense. I never understood letting the water go into the radiator and then sending cool down water to the thermostat mixed with some hot water from a bypass just to confuse it to want to open and close constantly. It isn't just the big bypass it's stupid it's the thermostat being Downstream of the radiator

[@gmeyer6657]

Correct..well said!

[@gmeyer6657]

Best mod I have done to my 04 Disco 2

[@jesper.schmidt]

If this simpler routing of the coolantsystem on the Discovery II is really a good idea, wouldn't you have thought Land Rover had made it that way, instead of the completely different and much more complex routing they opted for from the factory? As far as i can tell from the video, the original thermostathousing connected the outlet from the waterpump to the intake on the engine, so that coolant could circulate back to the engine, in the period when the thermostat is closed. That does not seem like a great idea to eliminate. Unless there is another way for the pump to be able to circulate the coolant from the waterpump when the engine is not hot enough to open the thermostat, there will be absolutely no coolantcirculation internally, until the thermostat is open. Another really bad outcome of this, is that the thermostat will take WAY too long to open, because there is no way for the heat of the engine to transfer to the thermostat, when water is not being pumped by it (like on the original setup). It will of course eventually open, but it will definately take longer, especially when it is sitting in a hose away from the engine. This is as janky as it looks. I would for sure not run that.

[@jamesray3920]

I believe you have the wrong color antifreeze in your D2 it should be red