I replaced the O2 sensor that was giving a code, but the one I removed only looked months old, and the code did not clear. I read there is a heater circuit involved with it, is there? Any thoughts on what would make a new one not clear the code? Do I need to put some miles on the truck?

Still overheating, SOB! I am gonna pull the radiator and open it up for a cleaning, and this will also do the full collant drain(which I hope will remove all air in lines)(not had the bubbling sound since the 1st overheat).
Question, I peeked under the shroud and I see a plastic tanks/aluminum
radiator, should I assume it is a replacement or did they come stock this way?
PS, my coolant system stays pressurized overnight, hoses are still very firm to squeeze after an overnight sit and cooled down. And after I think I got the entire coolant system filled, each time I try to remove the resivoir cap to top off the tank, I can't because coolant is forced out the cap from the pressure still in the system. Full?

Oh gosh, I gotta type a bit more. I had the P0118 code, it cleared and did not come back(but assuming it may take some time for it to), think I should replace that temp sensor before ripping the rad apart? Assuming it is the original rad and not replaced.

Thanks and eveyone enjoy their weekend in their rover.

EDIT: After some early morning fooling, I find the entire radiator cold to the touch. So I believe it am clogged. Interior heat works on and off.

 

Stock radiators have plastic tank aluminum cores.

Reserve tank should not be 100% full. Fill to 1/2 way, there has to be air space in there for coolant to expand.

Holding pressure overnight is a good thing.

Radiator being cool all over is a bad thing. All the cooling your truck has is the heater core. Most likely is not a partial clogged radiator, as then it would tend to be hot on top and cool on bottom. More likely a thermostat not opening. If stat was replaced, could be that an after market unit was used. Have had reports of bad batch of those not opening. Use oem from dealer. Good idea to remove radiator hoses and reverse flush (rag keeps some water from leaking out the bottom. How much water? The water pump is rated to move 2.6 gallons per minute at 1000 rpm. So at fast idle, should move enough water to fill a 5 gallon pail in two minutes. If you go so far as to take rad out you can take to a shop for hot flush and even rod out. Some try using a chemical flush, or the old school white vinegar (dissolves some of the calcium build up). Don't try the old school muriatic (brick washing) acid flush, that is way too strong and will eat aluminum. Just use a garden hole and see how long it takes to fill up a bucket. If under 2 minutes, radiator should be able to flow that without any problems. Doing it in reverse direction will bring out flakes of calcium build up, but may not get it all. You can have a gunked up bottom of radiator that will flow good from top, but you have lost the cooling from the bottom since water does not go thru there.

Heater works because it water flow through it in parallel to the radiator. ON/OFF is because the bypass function of the stat is kicking in as engine speed is increased above idle.

Suggest you flush the rad (reverse direction) and consider a new stat. The stat has holes in the top fitting that let a sample of hot water enter the stat, if these get clogged up with the flushing, you will continue to have overheat problems.

Pix of stat holes, dexcool sludge radiator, and coolant flow attached.

 

I got the whole front end and top end of the motor off all the way to the heads and still cannot find the thermostat! WTF! I am leg pulling. Just imagine how mad you would be to do all that, then realize you took it off 4 hours ago. I will do the stat first just incase. Looks like I have to special order the 195*C thermostat, only the 75*C is in stock, yeah, leg pulling again. Have a Great weekend Buzz.

 

If your standing I front looking in, look at the left side of the radiator its a big bulb unit 3 hoses inline.

I really hope you search stuff first if you can't find that I'm a bit concerned your getting in a bit deep.

 

In the drawing I sent from the RAVE it is # 16. Cold in the bottom, out to water pump on the "arm" and the top is actually water (hot) from the engine, sampled by small holes in stat, to make it open. Pix of stat above is looking down into the top hole.

 

I work in lab surplus, and we have many 3 way glass T's in the same shape as the thermostat housing. I am gonna look around Monday, real stat arrives Tuesday, and see if there is an exact glass T, be neat to film the coolant flow (or in my case lack of) thru the clear glass.

I was just kidding above, about taking the motor apart to find the t-stat.

 

The thermostat housing has stuff inside (a bypass thermostat), so a glass T would not perform well IMHO. It also is not a pure "T", has chamber and valved openings.

 

Well, I got the t-stat off and the PAS pump with a new gasket.
Looks like the insert for the bleed screw was lodged in the t-stat, so once I cleared that out the t-stat worked fine on the stovetop.

See if I can flush the rad and reassemble tonight, PLEASE WORK!
So I can fix this miss and use this beast!

The lifter noise was pretty noisy without the PAS pump squeeling.
Gonna do an engine flush in case a rod or lifter is clogged, the motor
does look pretty dirty inside, than add the heavy weight oil and see.

 

heavy weight oil? 15W40 is a standard oil to use in this engine. See https://landroverforums.com/forum/di...estions-46975/ (despite the name, it is a very informative thread)

Might be a good time for a mechanical oil PSI gauge test.