Hi everyone,

Just thought I would share:
Friday in the middle of PA temps were around 98 degrees. I was very impressed with the stock cooling system performance of my Disco. Travelling up into the Poconos going 75 up the long grades I never saw engine temperatures go past 212. The viscous fan kept engaging and disengaging as well as the electric cooling fan which I was very impressed with. The electric fan would bring the temp right from 212 back down to 194! The truck has 142k miles and is on the original radiator. Only the water pump has been replaced. What a beast!

 

The stock cooling is not horrible in its efficiency, the problem is that the dash gauge is/was useless. By the time it indicates a problem, it's too late and you'll have engine issues.
Having a working gauge is critical, as the Land Rover will continue to cool efficiency until it is out of coolant, then it will spike a temp and you have to pull over immediately.

 

Yeah, this. Stock cooling is good enough. The water pump doesn't flow quite enough at low rpm, so it'll overheat at idle with the AC on in hot weather, but overall it's good enough. But the stock gauge is crap. By the time it starts moving, the head gaskets are usually already done for.

 

Boy, if you are comfortable with that performance you are braver than I am. And I can do a head gasket job in 12hrs....

 

the stock cooling system is fine until it isn't. i have pulled work trailers and pontoon boats with my '04 with the stock cooling system and a 180* F thermostat. in 90* weather the Discovery ran pretty warm and i had to drive much more slowly than was sometimes safe on the freeway, especially on long pulls up the Ozark hills.

i recently switched my daily driver '04 to the Inline Thermostat (Extinct's version) and was able to pull a fully loaded 6x12, double axle trailer in 90* F plus weather at 70 mph with coolant temps never going over 203* F.

this was not the case with the factory setup.

i guess the stock cooling system will work fine for those who live in an area where the ambient temps never get above 80* F; but here in St. Louis where we regularly see temps in the high 90*s in the summer it's just not enough to keep the engine in safe temps when the Discovery is fully loaded or pulling a trailer.

 

Stock cooling won't work well when combined with towing and climbs.
I've had stock cooling in 110+ temps, in Death Valley. It provided acceptable performance then, but I'd never try that while towing anything.
As an FYI, almost nothing in my cooling loop is stock anymore, save a few hoses, as I have an Alisport radiator, Cars4x4 coolant tank, Flowmaster water pump, and Extinct's inline mod.
But I tow, and I want to tow in the heat of Summer, so my cooling is overkill.
The vast majority of people could get by with stock towing, with the caveat that a reliable method to check coolant temp is required.

 

Well maybe not not exactly on point but I flat towed a fully load LR3 ,about 6000lbs, for about 18 KM this weekend. In 1st gear running about 2100 rpm at not more than 20kph/12 MPH. The road was a rolling FSR with several significant uphills, the Disco never broke 185 with the Extinct inline kit, now it was cool out but still pretty nice performance.

 

@Mntnceguy My number 1 biggest issue with the stock thermostat on a D2 is the location it is at the bottom of the cooling system, on an engine that had it the standard V8 top location for decades. When I had an actual grey soft spring 180, in the stock position my Disco held temp beautifully, but given the total crap show getting of good OEM thermostat style not to mention cost, in my opinion the inline mod is simply a better solution.

The OP expressed is opinion on how well the stock system is working for him, nothing wrong with that. In fact it is less harmful to any new disco owner than the every tapping noise is slipped lifter stuff I see regularly.

 

Agreed, I think most people on this forum have an interest in maintaing their vehicles, either out of necessity or general interest. They are getting to the age where the plastic components will simply fail from age, heat, etc. Given a cooling system failure is likely catastrophic for most people, if your going to either PM it or repair it, an upgrade is a reasomable thing. Personally, in my history, I had 1-2 road side cooling failures and it is simply not worth the hassle of replacing parts w the OE when there is a better alternative to a known weak point in the truck. I installed the inline a few years ago when I had ticking, it fixed it for a while. Then I had the cylinders pinned by Rover Master Tech, on this board, in NJ. The truck has, knock on wood, been flawless. Except for this rattle I cant seem to track down. The wealth of knowlege and helpfulness on this board is equal to any other. Certainly helps keep them on the road. In fact I had a guy stop me the other day asking if I would sell my truck. I should have gotten his number, bc now that this one is completely sorted I have ran out of thngs to fix. Maybe need to start a new one.

 

I wouldn't consider leaving my cooling system stock. Not enough coolant flow at idle, unreliable gauge, barely adequate radiator, etc. The first thing I did when I got my Disco was to overhaul the cooling system.