2002 d2 115,000 miles 170,000 km
So my (new to me) 2002 has decided to do its best to **** me off.
Have been driving it for about 3 months , since I put a water pump on it and put it on the road.
Has been running great. No lights, no leaks no problems. Until recently. I keep my acutely 802 plugged in and temp. Has been steady at about 200 -202 deg. Made a 1200 km trip to Quebec 2 weeks ago and trailered back a 57 series 1 that I picked up (cheap basket case project)
I had noticed that I was loosing about a litre of coolant every couple of weeks (500-600 km)
Monday this week left work and drove about 5 minutes - in town driving, stop and go. Temp gauge was the usual 3o clock position as always. I noticed the temp gauge on my scanner reading 217deg! W.t.f. I pulled over right away.
Popped the hood and coolant was a little low. Looking around I noticed that the thermostat was damp... No puddle just wet.
I have been planning on doing the 180 degree stat change but had not yet got around to it.
Topped it up and limped it another 5 minutes home. No problems.
I got on the Internet and shopped around for a 180 stat. Figuring that it would be a few day to a week to get one shipped, I decided to deal with the immediate problem ( leaking thermostat) thinking that would be the safe thing to do.
I pulled the thermostat off my 2000 d2 which has been sitting since this new truck went on the road. Installed it and went through the usual pain in the but bleeding ( raising the resivor etc. Made sure I had good heat and no signs of air. Still running at 210 - 220 deg. 😩😩😩😠😠😡
Rechecked my work nothing unusual just hot.
Re bled it no change.
Thermostat was fine in the other truck. 2 hoses going in the top are good and hot but hose on the bottom is not (quite cool actually)
Thermostat is not opening....... Am I right?
Ordered a stock thermostat from a local supplier, SAME temp.
What am I missing?
Gets warmer in city driving than I would like. Drove it at a steady 80 kph / 50 m.p.h and temp is about 205 -212deg
More airflow lower temp
Shifted into 3 to increase r.p.m. Temp is 202 -207
More r.p.m. Lower temp.
Thermostat still feels cool on the bottom hose.

Today I decided to eliminate the fan clutch and switched it - no change
Removed and checked the radiator, seemed to flow o.k. But what the heck, I have one so I changed it too! Even if only as a test😕
The only difference between the 2000 and the 2002 is the temp sensor in the passenger side lower tank.
Still the same!
Checked the cooling system with a gas analyzer. Seems o.k. Pulled plugs nothing unusual checked oil o.k. nothing out the tail pipe.
I have been lucky with both my d2s so far and have never had a head gasket or bad block yet. Has my luck run out?

My question is why is the lower hose. ( Thermostat to the rad) always cool?
Bad thermostat x2 ?
Bad water pump not moving enough coolant?
Plugged rad x2 ?
I am waiting on the 180 stat but now question if I have something more going on
Any ideas, help, advice?
Feel free to comment

 

Thermostat isn't fully open until 96*C (204*F), that's when it sends the hot coolant through to the radiator. Unless your at that temp while sitting it's blending cooler coolant with the hot coolant and sending it through the system with the bypass portion of the thermostat housing. You would need a cooler temp thermostat to feel it running through while sitting.

 

I would really want to know where that liter of coolant is disappearing. Do a pressure check of the cooling system, should tell you where it's leaking from/to.

 

X2 on the coolant loss but I would also check your hose clamps if they have been replaced with screw type clamps. I thought I had a HG leak, a bad water pump, etc once and found out that my hose clamps had just gotten a little loose. Of course, I have also found actual HG leaks a couple of times, too... It is a Land Rover.

If you are losing coolant you are gaining air and air pockets can inhibit coolant flow, resulting in crazy high Temps and over pressurization of the system from steam. HG will blow or a hose will pop off. I'm betting the source of your coolant loss is the source of all of your problems.

I'd get the 180 soft spring thermostat if you haven't already ordered it. The one for diesels. Gray. Or do the inline thermostat mod--you clearly know what you are doing, so the mod would be a snap and I've never heard of anyone regretting it. I sure don't. The stock setup is designed for passenger comfort, not engine happiness.

 

Update
180 soft spring stat, re flushed and bled
Runs perfectly 180 -189 deg.
No coolant loss
All is good