Hi.
Am running an inline too for seven years now, and a much larger radiator. Without thermostat in summer; with thermostat in winter to avoid running too cool for too long time until running temperature stabilizes. It is only two easy screws to handle twice a year for removing/replacing.

ANY thermostat of any kind does restrict coolant flow somewhat in any inline or not location. If the cooling system is performing marginal, it does make a difference removing the restriction.

Post #8 at ----> https://landroverforums.com/forum/di...rmostat-67535/
Post #9 at ----> https://landroverforums.com/forum/di...ck-back-61395/

 

That is an interesting idea about no thermostat in summer. Here in CA the temps are pretty variable. I am not sure if I could get away with no stat.

What type of upgraded radiator did you use? Can't find many people who have gone that route.

 

Takes some adrenaline, but check s l o w l y posts 16, 18, 26, 28 at
----> https://landroverforums.com/forum/di...e3/#post512018

The one I used was ----> https://s588.photobucket.com/user/In...c2479.png.html
That is a screenshot of the vendor when I bought it and instaled 7 years ago, still like new today. Perhaps the 'Northern' numbers are still valid.

 

Here's how I was taught... The lower the opening temperature of the thermostat, the less time the radiator has to cool down the fluid within.

The fun test for this situation would be to put a higher opening temp rated thermostat (is the factory one 195 degrees?) in for a comparison. It may be the margin of difference the system needs to cool the fluid being held in the radiator when the thermostat is mostly closed down. Or, you find out that the radiator, even when new, is not good enough at cooling (which would be a shame).

Remember that the thermostat cycles throughout operation. It just doesn't open one time when the temperature is reached. When it senses it's time to open, it does so and allows the hot fluid to fill the radiator and the cooled fluid to leave the radiator. That cooled fluid will bring the temp down at the thermostat and the 'stat closes down a bunch or completely. Now is the time the radiator gets to cool down the hot fluid. It needs to be efficient enough to cool enough before the next rush of hot fluid is allowed in. If this cycle is not allowed to work well, by putting in too low of an opening temperature 'stat, then the system can't control the temperature well enough and it tries to, or does, overheat.

 

This thread is giving me a headache.

1. Remove your thermo completely and drive it up the hill. If it still overheats then its not the thermo.

2. You have a new radiator. You don't need to upgrade it.

3. Maybe your fan/ clutch. The stock ones tend to grenade anyway so do the hayden doorman upgrade for $100. Cheap insurance.

4. Check your ac compressor. If the bearing is out it might be loading heavy causing overheat.

 

you put a 200° temp thermostat in a Disco....you might as well go ahead and order the new head gasket set at the same time you order the thermostat.

there is a reason LR listened to the enthusiast community and began making all the OEM replacement thermostats 180°

I’m no expert...far from it; but I have had to do the head job; and replace the water pump. Have you replaced the pump? When I had to replace mine, the internal fins looked like someone had took a sledge hammer to them. The bearings on the pump pulley had disintegrated and the fan was flopping around like a fish.

so I would suggest making sure you have no play in the water pump pulley and if you believe there is...replace the pump for good measure.

I will add; I do not have the inline mod; though I am running a 180° thermostat. I have seen my temps average 183 to 185 since the thermostat change. Two weeks ago in heavy traffic on 100° plus day, I saw it get to 189°....I’m thankful for those numbers.

 

The D2 OEM 'stat is 190 degrees, not 195 (had domestics on the brain). Never heard of a 200 degree 'stat.

All OEM replacement 'stats are not 180 degree. And, 180 degree stats existed before any enthusiast community had something to say.

I'm no expert, either. I've swapped multiple engines, transmissions, and axle housings for multiple makes and models, not just LR... and the bits attached to them, to include water pumps. Knock on wood, I've yet to have a transfer case fail or need replacing. Rebuilt an engine or two back in the day; have not rebuilt any transmissions. I leave ring and pinion installs to the experts. I used to find doing the things I could do enjoyable... not so much anymore. I'd rather be doing other things.

All this doesn't change how the thermostat works, which is what I explained. I wonder if some folks have an inaccurate idea of what it does, and the affect it has on the cooling process. If one understands what's happening then you can properly interpret the changes observed after swapping one. It is possible to have worse cooling when switching to a lower temperature stat.

The other reason higher temp thermostats came about was for cleaner emissions. If someone was just squeaking by on an emissions test with their 190 stat, they may find that they are now failing the test with a 180. Just another consequence of switching 'stat temps.

In the domestic, old muscle car work many years ago, folks were installing 160 degree 'stats following the same logic being used here... lower must be better. But, many were having the opposite effect that lowering the temp was resulting in unanticipated increased temps, sometimes to overheating. It doesn't happen every time, but it's something to be mindful of when playing with different temp 'stats.

 

ALL of the OEM Disco replacement thermostats made after 2004 are 180°....it says so, right on ABs website and in the video they use for the replacement tutorial.

The issue I was trying to address is simple; the temperature failure for the head gaskets on the Disco hovers just above 200°; mine failed at 210°...I only know because I was dickering with my Torque app when the damn thing went to hell in a hand basket. Using a high temp thermostat pushes the system too close to the being before providing relief.

im not sure what the rest of your diatribe has to do with knowing that having a thermostat that opens at lower temps to provide increased flow without pushing it to crucial boundaries before opening is relevant.

 

That's too bad. Carry on.

 

I've seen a Rover V8 go all the way up to 239F and live to tell the tale with no issues. LR's were running 200-225F long before OBD2 Ultra gauges or monitors were out to monitor temps.

The engine can handle temps up to 220 no problem, but LR engines aren't getting any younger so yes it's a good idea to keep it as cool as possible, but within reason. Anything lower than a 180F is going to truly mess with the emissions, MPG, HP, Engine ECU especially if you have SAI as P0126 will be your friend for life.

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