I have read that the impeller is staked onto the shaft and will get to where it is spinning rather than pushing the coolant thru the system.

I too wish there were a drain installed to drain the radiator. I would guess a modification could be developed to incorporate such if one were so inclined.

 

If you want a test of water pump, without removal for inspection, here is the spec from the D2 (same pump):

Coolant pump output at 1000 rev/min 10 litres/min (2.64 US galls/min) at 0.7 bar (10 lbf.in2)

So in terms of pump power, it is nothing like your hot tub pump. But you can take the stat out, close it back up, and run the hose into a bucket, easier to play with cool water.

As gunky as original coolant was, any slipping pump shaft had long ago rusted firm.

Or pull off the supply heater hose and shove a small pressure gauge in there.

 

192 is the OEM temp.
I run a 195.
I do not recommend the 180.

 

Ahhh, just like the great oil debate...the best t-stat value! ;-) Well since the high temp here tomorrow is 5 F, I guess it couldn't hurt Spike! I've been so paranoid about running this thing hot and now all of this drama...I've never run anything more than 180 in my vehicles but this is the newest one I have really worked on besides my F250 (2000). I actually increased the t-stat on my truck because that's the way IH designed it to run...not what the weenie emmisions guys at Ford said it should be! Counter-intuitive though.

Back to the LR...so I had to run out tonight and it's a full-on blizzard. I discovered a few things, the rear fog-lights are handy, CDL works great and my rear defrost even works with a couple inches of snow on the rear window!

I got thinking about the heater valve tried fooling around with the heat and noticed something odd. If (while the temp gauge is climbing) I crank the heater temp to full cold, the needle will plunge back down to normal almost immediately. I ran this way for most of the drive home. Once it got a bit chilly I would rotate the **** back to hot and sure enough, the temp needle would begin climbing. Thoughts?

Thanks as always guys.

 

This is when I really like my rover.

 

re: crank the heater temp to full cold

Closes off the bypass flow path to the heater, increases pressure slightly downstream in the rest of the system, and that bubble that is keeping the thermostat company is pushed away. Turning back on flows coolant into heater core, reducing fluid level in cooling system even more. You are low on coolant and too full of hot air ( we hope it is hot air and not exhaust gas). While all of this fun is going on, hopefully you are not having a loss of coolant, like from a leaky hose clamp under the coolant reserve bottle where it is hard to see. Of course, wind chill with 0F and 40 mph is like -53 F, so antifreeze % has to be on the money.

No matter which stat you run right now, it should not be causing overheating. Just like you have boiled your thermostat for testing, what if the gauge sending unit is off spec? RAVE does not have a "curve" diagram, but says resistance is 136 cool and 17 ohms hot. Gunk on connector at sensor can impact reading. You could use an ohm meter and measure yours when temp indicates say "10:00" Have to pull wire off and read ohms to engine block. You could later remove sensor, and place in coffee cup with hot water and repeat measurement. Of course an IR thermometer could also confirm things are at "X" temp at the thermostat housing, which should be close.

 

Thoughts........ the motor lost a couple of freeze plugs while sitting on ice at the storage company. Maybe the valve was damaged. A little odd that it would show up now but you've been running the truck more than it probably did for a year or two. The fact that your hearing the gurgling through the heater core.....I don't know. It's normal to hear it in the core when air is still in the system but you also hear it overheat through the core too....sounds like Rice Crispies on steroids. Is your floor, underlayment wet? Stupid question.....I know but you may have a heater core going south, sucking air.

Heard on the news Seattle can't drive in 6" of snow. Hillarious!!!!! They abandon their cars! We get 6" of snow and we don't even break out the snow shovels yet, just leave it, there will be more.

If and when you discover the problem you'll appreciate the 192, your eyebrows will get singed when you have the selector on the dash vents and you won't have to trim em. Seriously, it has to do with the atomization of the fuel since these things don't even burn what they get injected....hence crappy fuel mileage.

 

That doesn't sound stupid at all.

 

In addition to potential heater core issues, did you have radiator flushed and rodded out? If radiator was full of gunk, you could be at a point where the heater core was actually holding almost as much water as the radiator, so switching it in/out of the plumbing circuit would cause large swings.

While it would be a cold test, if you bypass the heater you could test for thermostat perfomance with that part of the system isolated. Would also give you another chance to reverse flush it.

Somewhere there is plumber with a Disco who has installed a "T" in the heater hose, with a couple of valves and short length of pipe to trap bubbles, and be able to purge them.. Kind of like the pipe stub at the end of a line to prevent a "water hammer" at the sink or bath tub.

 

Good stuff guys. I'm going to try some of this when I finish up with work this week.

IH the sound has always been like running water and air 'swooshing' or more like gurgling around. I would never descibe it as hyper-crispies. So that is probably good. What worries me is the sound comes back while revving the engine...meaning either the WP is pushing it around (with more pressure at higher RPM) or exhaust gas is getting into the system. I haven't checked the floor for moisture yet.

SB the rad was flushed, acid-dipped, rodded and flow-tested. The same gunk that was in the rad is no doubt clogging the heater core too. I just figured I would lose efficiency re heat not have the issues I am having now. If the HC is bad I will likely bypass it and run some kind of aftermarket setup. No way I am going down that road! There is nothing in the way of coolant on the ground under the rig. Also there has been no further coolant loss that I know of but I have been burping the system quite a bit so I've had overflow and refill going on.

When I get the new hoses I'll try and back-flush the HC. If anything that should help force out any air-bubbles as long as I can re-seal it without allowing more air back in.

Thanks again for hanging in there with me guys...