I took my old thermostat and drilled small holes in the plate, as someone suggested. I drove around today with the sole intention of trying to replicate those conditions where overheating would occur. To my surprise, the temp held steady.

Has anyone else tried this, or something similar? Im curious to know if this is more harmful than good?.

When you say that you drilled holes in the plate, I take it that you mean the outer metal plate of the actual thermostat its self!? This isn't harmfull what so ever. Basically all you are doing is by-passing the thermostat mechanism allowing the hot water in the engine to "escape" (which the stuck thermostat was preventing it from doing) towards the radiator. Ideally though, what you should be doing is just replacing the whole thermostat. It's only a two second job when you're in there, it's just a tight (or loose) push fit. Don't buy a britpart thermostat because the one I have decides to stick open all the time and my engine runs too cold. Luckily, it doesn't stay closed.

The one thing that you may notice is that you actually loose performance. Diesel engines run best at higher temperatures (ie. 86 degrees C) than cooler temperatures. The whole purpose of the thermostat is to regulate the ammount of hot water that is allowed to escape from the engine block. By-passing it will pretty much allow a continous flow that is as cool as your radiator can get it, and with my N/A thats just above the lowest mark on the temperature gauge!

-Pos

Pos... theirs is a V8 merkin spec 90, not a diseasal, so shouldn't make a lot of difference to economy running it cool. Running it hot will make a huge difference as it'll eventually blow a gasket or drop a liner and then suck all their money out of the bank

Adz said:

Pos... theirs is a V8 merkin spec 90, not a diseasal, so shouldn't make a lot of difference to economy running it cool. Running it hot will make a huge difference as it'll eventually blow a gasket or drop a liner and then suck all their money out of the bank

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Ooooohhh! I thought it was like a tdi or a 12/19J. Silly me

pos said:

Ooooohhh! I thought it was like a tdi or a 12/19J. Silly me

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assume the position. Tweets is gonna spank you.

Thanks for the insight, more information never hurt. I actually did replace the thermostat at first. Only after I saw no improvement in the temp did I take the old thermostat and drill holes in the surrounding plate as an expairment. I first started out with 4 3/18" holes, and she still ran hot. Added 2 more 3/18" holes and there is noted improvement. Overall she runs cooler and more importantly will cool much faster when she is hot. I ordered the new thermostat from Land Rover. Should I have gone aftermarket? Whatever drilling six holes into the thermostat did seems to work, I just hope I'm not messing up anything else long term.