Cooling System Conundrum Part 2 - Thermostat Mod

In this video we perform an inline thermostat modification on our 2004 Land Rover Discovery 2. Here's the link to the thread which showed us how to do this modification: landroverforums.com/forum/dis...
If you'd like to reach out to us directly, please send an email to [e-mail]. Please subscribe to help us reach our 100 subscriber goal!
2004 Land Rover Discovery Series II
Land Rover Discovery 2
Inline thermostat modification
Timestamps
0:00 Intro
0:59 100 Subscriber Challenge
1:17 Why mod?
2:23 Testing the new thermostat
3:25 Thermostat housing
7:03 Removing old hoses and thermostat
8:29 Disassembling the new hoses
11:29 Installing mod
18:19 Disco is back online
18:27 How it's working so far
19:34 Outro

[@juaco112]

i love how you get your kiddos involved, they will learn tons and will never forget the experience. greta dad stuff, i got a D2 because i like them but also to bond with my kiddos.

[@gmeyer6657]

Hi..Glenn in AZ. How is the thermostat mod working.. ? Cracked 2-89.00 plastic thermostats here in hot AZ. Have replaced all hose connections with the Aluminum ones & Aluminum overflow tank. I also replaced the old heater plate with a “brass one” from Falcon Works in TUSCON, AZ. Great video & nice family. All the best!! 🤙🏻 🌵

[@zubin7026]

Hey! About to install the inline system myself, just curious how you bled the system?

[@patrickdanforth7700]

I got my 04 in 2012 rebuilt the engine put in 180 thermostat I think I had a back pressure failure so assuming the thermostat finally is failing only happened 1x at a drive thru. I heard about inline. Spent the last few days searching inline videos. Found 2. Since being an owner I have replaced muffler more than anything else they rust and break off at the flange between muf/tail pipe silencer. The first few rime the tailpipe falloff and got lost. This time it hung up so I still have it to reattach. I run obd2 elm with torque app to keep track of temp and been flawless for 10 years. So 10 years I think not bad. So looks like next is I line for me. I run distilled only from April to September and 70/30 green coolant/distilled for winter. My hoses are still in excellent condition just a choice I did to slow wear on hoses. I don't have any oil leaks since my rebuild. But its time to do the valve cover gaskets and new bolts as I noticed the outer bolts are starting to loosen on their own now so prevention time. My magnecor 8mm holding up well. Don't wanna do the coil pack ever again. Note on the 2nd AI. The pump hose gets brittle and cracks.

[@ronaldrrootiii6040]

The inline thermostat is so simply great and the funny thing is is really it's just a traditional thermostat even the Rover V8 when it was carbureted had one up on top. So my problem with the original three-way design is number one the bypass is way too big when really it could have just been a small metal hose coming off the water pump and not getting involved the way it does with the entire cooling system and number 2 my biggest issue is that why would they place the thermostat Downstream of the radiator? Shouldn't the thermostat be reading the temperature of the water as it comes out of the engine to make its determination on opening and not after it's been cooled from the radiator? And let's go back to that bypass let's say theoretically it closes all the way but now you have water being pushed down a hose that is leading nowhere and needing to just sit there and slowly do a U-turn and go down the other hose to the radiator. And again if the radiator cools the water down why would you send it to a thermostat after it's been cool that's like putting the air conditioning thermostat of your house right next to an air vent register to blow on it and make it think your whole house is cool

[@alanm.4298]

Hi! I drive an older Disco. Different cooling system. AFAK, no need for rhe inline t-stat mod. However, having driven the beast for 20 years, servicing it and all my cars and trucks mostly myself all my life, I can give you some suggestions. First, that plug in the t-stat housing you installed probably is to be used to bleed air out of the system. Second, switching to a 180 t-stat from a 190 does nothing to prevent overheating. An open t-stat is an open t-stat, regardless of its temp rating and either is well below the overheating. All a cooler t-stat does is open sooner, slowing down how quickly the engine comes up to operating temp, which is probably around 205, 215. Under normal driving the engine will reach that temp no matter what rated t-stat is installed. At idle there may be a difference, depending upon the overall efficiency of the system. But at peak temps where overheating can happen it makes no difference. In race cars we would sometimes remove the center from the t-stat or leave it out of the housing entirely, increasing flow at all temps. But that is not wise for a street vehicle because it can allow too low temps where the engine will not run efficiently. I proved that 180 versus 190 makes no difference during steady driving when I swapped a cooler t-stat into my own Disco. I have an OBD scanner that gives me exact temp readout live data, and when I used that during normal driving the engine reached and stayed at the same temp on the highway no matter which t-stat was used. Probably any improved cooling you are seeing is because you drained off some of the old coolant while doing this and replaced it with fresh. That can do as much or more than anything else. Depending upon mileage driven, it is a good idea to completely drain and replace the coolant every few years. A "flush" may be helpful too. I don't use the 50/50 pre-mix either. I buy pure coolant and mix it 70% coolant, 30% distilled water (to prevent mineral build up in system). The higher % of coolant not only protects better against freezing, it also raisees the mixture's boiling point to help prevent boil over and overheating. I fully serviced my Disco's cooling system a couple years ago, trying several things to reduce temps since it can get hot here in Calif., plus I do some towing and mountain driving (liquids boil at lower temps at higher altitude). On the Disco 1 the only thing that made any difference in temps at highway speeds was installing a "Saudi grill". This was an accessory Land Rover sold for hot climates, that has a larger intake area to allow better air flow. I wouldn't spend money on one again though, because it would be easy to modify the original grill for the same result. I don't know if the same is true of the redesigned Disco 2. Other things in the cooling system to look for: Disco 1 came with a plastic plug in the top of the radiator used to refill the system during service. I don't know if Disco 2 have the same. If so, that plug should be replaced whenever it's removed. It really is single use and reinstalling it can cause leaks. I replaced with a brass plug that can be reused. Also check that your fan clutch is working properly. Over time with age they go bad and lose efficiency. Watch that your radiator doesn't get obstructed with leaves, insects, etc. I drive through a lot of farm country and have to stop and clean bugs off my windshield fairly often in the spring and summer months. Rather than have to spray clean the radiator often, I recently bought a screen mesh and will be fitting that to the front of the truck. That will stop the bugs, for the large part, and be easier to clean. (I'll watch to see if it restricts air flow and causes higher temps.) Doesn't effect the engine, but also watch your transmission cooler. On Disco 1 there are two temp sensors, I had one go bad and had to replace it. It was just the sensor, though. Speaking of sensors, my temp gauge stopped working. I found the problem quickly... When the truck wasn't driven for a week or two, field mice had made a home in my engine compartment and chewed through the wire! (They also destroyed the hood liner and I later discovered had set up another camp on top of the truck's gas tank, around the fuel pump housing. Thankfully they didn't go after the wiring there.) I'm not knocking the inline t-stat housing mod you did. In fact that may be a partial solution on Disco 2, which is set up differently than Disco 1. But don"t expect any peak heat reduction or overheating protection just from using a cooler t'stat. Whether 190 or 180, the engine under normal use runs hotter than that and either t-stat will be wide open allowing the exact same flow of coolant. Another thing, maybe it's improved on Disco 2, but I'm on my third coolant overflow tank. The first two started to split and leak at a seam. Also, and possibly more importantly, beware of cheaper aftermarket caps on that tank. One I installed either didn't seal well or didn't have the correct pressure rating and leaked badly. Fortunately I had tossed the old OEM cap in a box in the truck and swapped back to it... Still working fine. But if a problem is suspected, it's possible to pressure test the cooling system and those caps. (It also is possible to check the coolant system for exhaust gasses, which would indicate a head gasket issue.) Oh, and be careful about the RTV sealing things up. If too much is used and gobs of it break loose and start floating around in the cooling system, it can clog passages or interfere with the water pump or the t-stat itself.. I don't recall ever using any sealant or maybe just a thin bead of it on each side of a single gasket, when I install the t-stat in any of my cars. Hope this helps! I plan to keep my Disco for many years and try to maintain it. It's a little rough looking in some areas (paint, seat wear), but has been very reliable. The only time it ever actually broke down on me was parked right in front of a repair shop, when the original starter suddenly died! ☺ P.S. my next project is fuel injectors and the ignition system, looking for better had mileage!

[@DiscoLife04]

Hey Alan. Thanks for the comment! I've heard (through reading mainly) that the D1 has a better cooling system than the D2. Not sure how much validity there is to that. Reading up on the D2 most people recommend switching to the 180 purely to help prevent a fast overheating. Basically, get the coolant flowing faster. The inline mod (landroverforums.com/forum/discovery-ii-18/official-extinct-inline-thermostat-mod-thread-105010/) seems to have a lot of support for it working. I have an ultra gauge now and the truck hasn't been over 200 degrees since installing the mod. I don't know what it ran before though, so not sure if it's better or not. Usually the truck just oscillates between 170-190. I havent done a ton of maintenance on cars before this so I went with the premixed 50/50. I've read multiple opinions on what to use, and like most things there are many that are varied. I did switch away from the pink to green🤷. The D2 radiator doesn't have any plugs on it that I am aware of. Just places for the hoses to go.

[@DiscoLife04]

I did end up swapping out the fan clutch and the fan. When with a duralast heavy duty clutch and a Hayden fan (AutoZone had them in stock!) I will keep the radiator clean so that it allows the best access to the radiator, great tip. I'll have to look into the Saudi grill. I am not aware of that option for the D2. That might be good for being out on the beach. It doesn't get California hot here, but still gets warm. I hear the d1s are really nice as well. I have seen a few around. Our 04 is in need of.love as well. we have a few upgrades we are considering to spruce up the looks! Thankfully we love it and are also hoping to keep it for years to come!

[@DiscoLife04]

Oh and let me know if you get better mpg! I'm looking to replace the coils, wires, and plugs soon. Hopefully that helps some.

[@alanm.4298]

@@DiscoLife04 D2 uses different engine management, fuel injection and ignition system than D1, so what works for one may not work for the other. Three things most likely to effect MPG are oxygen sensors (especially the upstream), injectors and any air leaks. If you.look for O2 sensors, shop around. Prices vary wildly. I don't know what D2 uses, but I stick with NGK brand. (Spark plugs, too.) Best plug wires are Magnecor. I had a set of their top-of-line 8.5mm for a long time, but they are tough to fit into the various clips. Their 8mm or 7.5mm fit better.

[@alanm.4298]

@@DiscoLife04 I don't know if a Saudi grill was ever offered for D2. Probably no matter because even if there were it's very likely unavailable now. I think I bought the last one in the US for D1 many years ago and had it stashed away. But after looking at it closely, it would be very easy to modify the standard grill to work the same. You probably don't need it though, in milder temps. I see quite a few summer days above 100F. Plus I sometimes tow a trailer. And I do some mountain driving. It's not Saudi Arabia or even Phoenix hot, but getting close at times so I need to keep the AC on too! 😛

[@kevinfox2370]

how did you bleed your coolant system after install? I'm struggling with getting all the air out of the system.

[@yuhuang7096]

Do you have to bleed coolant after install ?

[@ctea8907]

Not if you oriented the thermostat correctly with the bleed hole at the top. This was the best $100 I've spent on my D2. Took me from the low 200's to the low to mid 180's. Essentially now runs about 100 degrees over ambient air temps. AlanM is a little off on his D2 cooling advice. Sounds like he probably knows a lot about D1's though. The D2's bypass circuit, which is removed in this inline mod, causes the engine to run hotter than it needs to...

[@clanforge4466]

The music overpowered your voice audio