Hole drilled in edge of thermostat??

[Bob696]

Took my thermostat out of my 200Tdi today and found a hole about 6mm across had been drilled through the metal disk bit.

Can someone enlighten me as to why this would be done? After all, if the water is hot the thermostat is open anyway so the only effect I can see is at low temp. Or am I missing something?

The engine gets upto temp a lot quicker now :)

[rokcrawlin]

the hole is meant to be at the top and is there to allow trapped air to bleed through it should have a toggle in the hole

[Bob696]

This is 6mm across!!!! Somebody drilled it. You can see the burrs. Got me stumped.

[hobbit]

6mm sounds a bit big, normally 3 or 4mm

Sometimes this is done, depending on the flow of the system, Toyota ace vans have a lot of this done, just increases the bypass flow through the stat.

Just means it take longer to warm up to operating temp, also acts as a pressure relief in case of the stat jammin closed

[yer auld aunt nelly]

nothing to overly worry about bud.Ive done it plenty of times on me old series its either that or take it out completly.But thats a whole different can of worms as no doubt someone will point out! But the up shot of it is if it works,it works dont worry

[Bob696]

I put a new one in anyway along with a temp sensor. I was getting a wierd problem of it showing overheating but the needle not dropping until the engin was switched off and then switched straight back on. It then went back to its normal point :roll:

Just done a 100 mile round trip and it didnt show any signs of overheating.

[hobbit]

Have you looked at the rad, for signs of wear, mine had almost disintegrated along the fins

[Wanderer]

You need to really worry when they've drilled the hole in the rad cap or expansion tank cap.

Eh Kev?

Ed

[hobbit]

yup