Toyota Landcruiser 200 series, VDJ200R V8 4.5 litre Commonrail 1VD-FTV Diesel EGR Blank/Delete/Reduce...High altitude power loss and water temperature was up 2 notches on the gauge!

My VDJ200R had done 90k miles and I've been having this "power loss" at high altitude problem.

My last two posts of discovering problems with the MAP sensor that was fed boost from the intake manifold and subsequent replacement of the MAP sensor hoses and air/oil filter did not completely resolved the problem!

It did help in restoring the car to shift earlier and was very good at close to sea-level cruising with the auto trans engaging, IMO, correctly!

Just yesterday, I returned from another high altitude trip and this time I nailed another clue! At the point of experiencing power loss I noticed my water temp gauge was up a notch or two! As soon as I gently give the LC200 a chance to let the temperature drop back down two notches, the car regained power!


I thought about the thermostat, first thing!

Viscous heater pump with magnetic clutch removed...after this it was easy to get at two bolts securing the steel pipe ending at the left hand side(view from front to rear of vehicle) of the thermostat housing. I did not even have to remove the thicker serpentine belt as the two bolts (12mm metric) securing the radiator steel pipe were accessible without too much difficulty!

Never having taken off the thermostat before, I thought that the removal was easy peasy until I discovered that the housing was built in to the water pump! In retrospect I would not have needed to removed any of the pipes on the right(view from the above!) of the thermostat housing! After removing the smaller width belt, the viscous heater pump assembly (see top pic) was removed.

Part No.16321 (Steel pipe) has two bolts top and bottom along the pipe(in addition to the other two at the thermostat flange)...loosen them and the pipe can be wiggled to remove the thermostat without having to remove the serpentine belt and other stuff.

This golden radiator steel pipe is your easiest path to removing the thermostat short of having to remove the entire water pump plus the serpentine belt and a whole host of other stuff!

Jiggle the radiator steel pipe a little and the thermostat was removed. Part of the rubber lips were deteriorated and missing! In the engine block I presume. There should also be a rubber gasket surrounding this thermostat. Buy a new one!

Boiled a kettle of hot water and poured it into a container with the old thermostat.

Dead thermostat. It didn't move much.

My thinking was that the water temperature played an important part in the safety feature of this 1VD-FTV. When temperatures get abnormally high, the ecu cuts injector duration or pressure, either way to save the engine!

At least that's what I think....now before jumping to conclusion I'll like to fit everything back plus a new thermostat and give it another high altitude run!

Check back later....