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Mr. t
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Discussion Starter · #1 ·
just had by coolant flush and new t-stat install done at a shop. i do this once every 2 years, but this is the first time i've let a shop do it. of course i get my rover back and barely even 10 minutes from the shop, my scan gauge is hitting 224-230f, so of course i freak out..

i've owned my scan gauge for 4 years now, and since then my rover has never really made it above 206ish. i've always used the atlantic british thermostats. and i've always felt that i've been in the safe range according to the reading i do, on this, and other rover forums.

my first guess is air in the system, but everything checks out with the standard (raise exp tank) bleed procedure, then the owner of the shop comes up there and hooks up one of the force pumps (not sure what they're called) and makes double sure that there is no air in the system. plenty of heat, no sloshing and no air in system during either bleed method. i'm satisfied and so is he.

still worried, i leave the truck with him while i'm out of the country and once i return, i find out that he's replaced my fan clutch and installed a new t-stat, re-bleed, etc..he then hooks my scan gauge up to a couple of other DII's in the lot and they too are reading 215f+, so he calls it good. he did that extra work for free by the way..good dude.

the truck is still running solid at 215-220f, and at stops has peaked up to 225f. but you can tell that the t-stat is doing it's job as you watch the scan gauge, no erratic up and down temps. i just really don't like the temp up that high.

he used a world-pac brand t-stat, which i'm told is the company that makes them for rover (haven't verified this on my own)

my question is:
to those of you who real-time monitor your water temps, what is your average temp range, and what t-stat are you using??

p.s. about a week before the shop did initial t-stat replace/coolant flush work, i replaced the exp tank with cap, the manifold to exp tank line (tb bypassed) and the radiator to exp line. ran it for a week prior to taking it into the shop and everything was peachy.
everything in the cooling system is under 2-3 years old, except for the radiator (original)
 

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I have the normal Thermostat and it does not get over 207-209. Even in summer in Chicago traffic.
 

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Is your electric fan kicking on when you hit 212? I have the 180 and normally run around 194 in traffic. Could your coolant temperature sensor be bad?
 

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Mr. t
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561 Posts
Discussion Starter · #7 ·
I have the normal Thermostat and it does not get over 207-209. Even in summer in Chicago traffic.

that was exactly my experience with my last t-stat.
 

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Mr. t
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561 Posts
Discussion Starter · #8 ·
Is your electric fan kicking on when you hit 212? I have the 180 and normally run around 194 in traffic. Could your coolant temperature sensor be bad?
yeah it was def running. didn't check whether to see if it was kicking in exactly at 212 though.
 

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Mr. t
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561 Posts
Discussion Starter · #9 ·
Arch I run the stock tstat and rarely get over 212 if never burp your system real good
josh, link me to that thread you mentioned. plz
 

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Mr. t
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561 Posts
Discussion Starter · #10 ·
so an update.

truck was still getting upwards of 225f even after they replaced the t-stat for a second time. like i said..i was used to 206-209ish at peak.
so i brought the truck home and attempted a few more bleeds, with no success (no more air came out)

then i raised the expansion tank and strapped it with a string. the tank was nice and level and suspended about 18" above the motor. i then removed the cap from the expansion tank, thinking that this would high vent the system. as long as the heat was on, it stuck around 212-215f, but as soon as i'd turn the heat off, it'd creep up to 220-225f then start boiling over in the expansion tank (no good). then i tried this same scenario with the cap on....the temps would do the exact same thing, but i'd get no boiling.
the whole time i was doing these test i was monitoring the heat (by hand) of the lower radiator hose vs the upper rad hose, and the radiator itself from right to left. the temp difference was extreme enough for me to think that the thermostat wasn't opening up at all, or that my radiator was completely clogged.

then i took the system apart at the radiator. i noticed no debris/scaling falling out of the radiator (caught it with a bucket). i then flushed, with light hose pressure, forwards and backwards through the radiator, still no debris/scaling, and it seemed to flow just fine. so just for the hell of it i plugged off the radiator and filled it with white vinegar. let it sit for 24 hrs, then dumped and flushed it again. still not a drop of debris or scaling and plenty of flow. the white vinegar was as clear when i dumped it as it was when i poured it in.

then i put in a new t-stat (the cheaper one from atlantic british) that i had laying around for emergencies. refilled/bled the system. now it runs absolutely perfect. riding temp is 193-195. sitting still it will occasionally bump 202f. it's never ran this cool.

so my conclusion is: both of the stats put in by my rover mechanic were either faulty, or possibly the wrong ones. the thermostat they put in looked exactly like this one

LandRover Discovery 92C 198F Thermostat

these are designed to warm up quicker and run hotter for colder climates, so i assume that was the issue????

a few things learned along the way
-real time/real temp monitoring is extremely important. had i not had my scan-gauge II, i would have never known that i was running temps so close to the danger zone. the stock needle is almost useless.
-you do not have to have your heat on during the bleed process. coolant is always flowing through the heater coil. this is the DII's primary source of heat exchange.
-i've used dex-cool forever. i've always maintenanced my system every 2 years (flush/refill). my radiator and all of my other cooling system components were in perfect shape. i'm currently at 230k'ish on the mileage clock. this might not say a lot for dex-cool, but it says tons for staying on top of your maintenance.
-in the service manual, rover is extremely vague about what peak/desirable operating temp should look like, they give no specific number, but they do tell when the t-stat is fully open..204f and starts to open around 195f. they do this because the t-stat is designed to operate differently depending on what outside temps are like. think sweden vs the desert, rovers are world wide and the systems are designed to encompass all of those environments. i think this is also the reason why the needle coolant temp gauge has such a wide variant in temp with no fluctuation in the needle. but this clue i found should give us americans an idea of where we are supposed to be...
the electric fan in the front is a back-up/auxiliary function. it is there for times when it's super hot outside and you're towing stuff up a mountain, etc.. it is designed to come on at, or around 212f (mine comes on at 207-209ish). so for those of you running temps in the 215f range and above, why would rover design a system that sets temp for back-up mode (electric fan kicking on) lower than the operating temp? this tells me that are systems, under normal conditions, should run a few degrees lower than 212f.

i'd like to thank josh cox for talking me through a lot of this. he dealt with some of the same issues i was dealing with, and provided me with tons of good diagnosing tips. thanks brother.
 

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Mr. t
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561 Posts
Discussion Starter · #11 ·
also, thanks to all the replies i got from the other members.
 

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Mr. t
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561 Posts
Discussion Starter · #14 ·
I would put those t/stats in a pot of water on stove with a thermometer & check when full open, just sain blamo
I quickly threw that 92c one in the trash.
If you look at that bpofutah link I provided, my stat (provided by Indy rover shop) looked exactly like that, blue dot and everything. I already called the owner of the shop and told him to check his other t-stats.


Sent from AutoGuide.com App
 

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Mr. t
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Discussion Starter · #17 ·
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