Search:

nah delo has been in my td42 for 20 odd years not a seep, nothing. i'd guess that a thicker oil might slow it down.

But I've just read you have a td42 so scratch that..
Um well I've run delo 400 in my td42 for about 10 years when it was on the farm..
It was our main truck oil so had it in bulk 44's and used it...

But it's funny.

No not at all. Fit the 3" exhaust, a manual. Boost controller and a Pyro then put it on a Decent Dyno and you will never doubt your descision. You will gain power and love the result.

Yes it's a pressure relief.

You can remove it and blank it off. But I would recommend fitting a boost gauge.