I’ve seen and read a lot of threads on inline thermostat mods and new severe duty clutch and fans mods. Is one mod better than the other? Do I need to do both? Opinions please. Thanks.

 

I'd do both, but the inline thermostat is the best thing you can do for these trucks.

 

I am also interested in this mod, there have been a couple of threads here, one of the kits seemed to be pretty pricey. I googled the subject, and this is one of the first results: https://inlinethermostats.com/land-r...38-inline-kit/
The question is, what is the best place to get a good enough, and yet affordable in-line thermostat kit... I gather all agree that it is a significant improvement to the cooling system as a whole.

 

That kit is just 2 stock style thermostat housing sandwiched together. The trick is to figure out which 2 vehicles they came off of. Then just go to RockAuto and buy both for probably 30 bucks. You need a buddy at a parts store warehouse that will let you rummage through thermostat housings. I’ve seen quite a few stories about the motorad brand housings in that thread being super porous and weep. I’d be willing to try other manufacturers housings or even by the 2 direct from the Honda dealer or whatever little 4 cylinder car they came off of.

 

I feel very strongly that the inline mod is first priority. I have “just” that and the stock fan and clutch at 191k and the cooling system works great. Now, I live somewhere pretty mild but I see that you are in Texas so it’s probably worth following up with the fan and clutch but the inline kit from Best4x4 would be my first step. After that you can examine your temps and see if the fan/clutch is needed.

 

just get hold of Extinct and purchase his Inline Kit.

i think it's roughly $80 or $90 bucks to buy his kit.

it's always good to support a guy who put in the time, money and research to find a solution to an issue created by goofy LR engineering.

 

This is going to be an unpopular post... but I don't believe in the inline thermostat mod. I have 2 D2's (that I'm looking at in the driveway as I type). Both with the original LR radiator and stock cooling fan and clutch (which is relatively new). Both using orange Dexcool that is changed every 2 years and vacuum filled so no air bubbles. One D2 has 112K on it, the other D2 has 40K miles on it.

Both run 190-194-200 temps with the 180 degree (grey) Genuine LR thermostat as measured with ultraguage. Last summer I did see 212 degrees on one of them when it was 118 degrees outside here and I was stuck in traffic. But that's fine. Anyway, I just do *not* see any need to modify for a new thermostat... I think it covers up other cooling system issues like a marginal radiator, air in the system or marginal water pumps. Besides the inline rips up the hood pad.

Now the PCV mod.. big believer!

 

Watch this video and the part where he explains the D2 cooling system. It might change your mind. LR designed these engines to run too hot - in order to pass emissions - but the engine/gaskets/etc were not made to withstand such heat. Give it one head gasket job then you'll be rethinking.

To make things worse, Dex-Cool causes overheating as well. Here is a class action lawsuit where GM was ordered to pay customers because of the product: https://www.classlawgroup.com/dexcool/
You can also google "dexcool sludge".

 

That is the one to get. From that site. It was made by user Extinct here on the forums. See the Inline Mod sticky on the D2 homepage here. I am a verified buyer and my D2 runs much cooler. No leaks, easy install.

 

My focus is reliability and performance when offroading. I don't want anything to fail prematurely when I am out in the bush. The inline thermostat and Hayden severe duty works great for me.

1) The biggest advantage for me is quick accessbility to the inline thermostat

2) I has been posting abiout my positive observations when switching from the Hayden 2781 to the 2991:

https://landroverforums.com/forum/di...-107475/page2/