So I think I need to replace thermostat, any recommendations on brand? So when I replace and refill with coolant will I need to bleed the system? If so what is the correct process?

PS I have some prestone dexcool for GM coolant, will that be ok to use.

Thanks!

 

I would bleed system anytime it had any kind of coolant surgery.

 

for parts go OEM only, at least for coolant system stuff.

Yes, you will need to burp the air out, and yeah it couldn't hurt to flush the fluid with new stuff. Prestone is great, that is what I use.

Process is don't touch the bleed screws or bleeder valve at the top of the block, BUT keep the coolant expansion tank cap off. Make sure everything is connected and closed up vis-a-vis the hoses, then fill her up.

Start the engine and run gradually up to 3000rpm for a few minutes until it warms enough to open the thermostat. When that happens it will suck coolant down and flush most of the air out of the system. Shut the engine off immediately after the t stat opens and top off coolant as necessary. Repeat once or twice more. You should see no bubbles in the coolant return. Then put the cap on. If you have a diagnostic tool the correct temp for the t stat to open is around 197F.

 

Is that true about the temp? Both my RRS and my LR3 (when I was diagnosing something else the other day and looking at live data) showed "low" on the gauge (I know they're totally inaccurate) - just below the center mark. ALWAYS. But the live data actually showed 177 - I remember it because I figured a more modern engine would run hotter like most today.

Anyways definitely bleed the system with a job like that.

Hopefully you can get away with not opening that upper bleeder. For the record, if you haven't replaced it yet - I'd go to the hardware store and buy some 1/8" NPT tee and hose barbs and a plug and make yourself an in-line tee where you can just unscrew the plug when you need to bleed it... should never have an issue with the plastic one cracking or blowing up on you ever again. Again - if you haven't replaced it yet, this WILL fail. I'm a big fan of doing cooling system repairs/upgrades across the board (if I do tstat, do a questionable hose - if you do a waterpump, replace a questionable fan clutch, etc).

If you do open or replace the upper bleeder, it takes a lot of raised-idling, refilling, burping, revving, etc etc etc. Eventually it'll shoot out.

...wait... not like that

...well anyways. The revised LR bleeding procedure is over-the-top annoying and complicated. As long as you're careful the key is to keep the coolant topped off and an eye on the temp gauge, that should prevent 99% of stupid mistakes. If the system gets too hot you'll just start overflowing out of tank and will need to restart the process later, but by then you should be almost good to go.

I think the rear HVAC probably complicates matters as well. It's about as frustrating as my DII which is to say... unusually frustrating lol.

 

Yes, AFAIK that is the temp range for the t-stat to open. I've attached about 2 hours worth of running data, and you'll see the coolant temp peaks from ~194-197. When I did my t-stat it was right after that temp range that the system opened up the loop. I am wondering if your live data was pulling numbers from reading an air pocket or something? No clue there.

If someone comes along and says no its actually way lower, I'll be surprised. I had a perfect bleed result/zero air, and used OEM parts only.

EDIT: this was the write-up I consulted when I did my own Thermostat job. He too mentions something similar (190F) as the threshold.
http://www.lrrforums.com/showthread....our-Thermostat

 

Somewhere on here (or another forum) I read a post about the bleeder valve failing and leaving the poster's wife stranded on the side of the road.

...I'd always thought that if you left it alone, it wouldn't fail; that it was always in the process of bleeding the system that the thing exploded.

What is the consensus?

 

I think the consensus is to just change it every few years (or every decade)

In rare cases they might be so heat-affected that it might just explode under the hood but most people on forums like these don't have that they end up breaking it while changing the old one. I imagine for every time one of us has done that there's some guy who doesn't wrench and had that happen to him, maybe just towed it to a mechanic who fixed it and he was never really aware of the whole problem.

Definitely carry a spare though. I have seen someone fit a bic pen body (tube) between the hoses and go about his day.

 

Mine exploded while driving. It was probably around 75,000 miles or so on the odometer and I hadn't had the car that long. Made it home, but could have very well resulted in a call to AAA. Not that cooling system issues are abnormal for Land Rovers. Our '04 Range Rover with the BMW M62 engine is a mess of cooling hoses, two of which have exploded while driving, leaving my wife stranded on the side of the road. Oh, and I had the water pump gasket fail on that one also... Good stuff.

 

Mine is fairly new....like 10,000 miles old. Perhaps having a spare and changing it every few years or 30k miles is a good idea. It's pretty temperate in WA state though.

 

People here mocked me when I said I dropped $60 on the Falconworks brass bleeder T. Now I definitely realize I'm ok with that. I will never have to change it or carry a spare.
That to me is worth it over having to worry and carry a spare and swap it every several years regardless.