The V8 Owners Forum -

I have been pulling the last bits off the 4.6, things I have noticed that there are what look like water stains on the outside of the block in each side below the deck, about the area of 5 & 6 bores, now I have inspected this block thoroughly and there are NO witness marks to suggest the liners are leaking, all pistons and chambers have a good healthy black carbon coating, its had a new water pump recently which looked like it had a leak from the pump gasket area. Looking inside the water jacket, it looks like new and no sign of any leak stopper, I dunno what to make of the water marks on the block,
So I suppose, I better bite the bullit and see if I can find somebody who can pressure test the block, Anybody in the SE
Im assuming there are only 2 inlet/outlets to the block, and 2 per side on the head mating surface, I suppose I could make up blanking plates for the top of the block and water jacket on the pump side, then put a Vacuum on the block, I cant see why it wont work, any suggestions????

And,

I know Rover used some sort of super permanent block sealer, what is it called??

Pressure test is easy once you've made up the blanking plates.

Each bank is independent, so you need 2x deck blanking plates, and one for the timing cover interface. Unfortunately the two ports on the front of the block are different, so you need one plate per side, or one big one like I did.

Chris.

just made a quick call and found a pressure test kit, so that has saved me a bit of effort,

Where / how much?

Chris.

My mates shed!!!

Did my pressure test this afternoon, and I think its OK, probably not tested the normal way but I pressurised the block to 100psi air pressure, then used a HiTec leak finder we use at work, spray it over the suspect joint, then, if its leaking, it turns to a white Vapour, I tried this on all liners top and bottom without the slightest whisp of white,

Hi Ian
just a thought, have you go a porous block? with the coolent finding a direct path out? I am pretty sure you can seal it up with an epoxy sealer if it is the case.
Mike

I dont think its a porous block, I know the water pump gasket was leaking at one time, It could be a witness mark from water that has run along the block, Ive had several people look at it, and nobody seems to concerned once you look at the marks logically, there are no marks on the deck to suggest its been leaking past a liner,, the marks are nowhere near the water passages, and the only other water mark is on the timing cover where the pump has been leaking.
I have also had one person say that their block had similar marks in the same place

In Finland we always heat block to approx +80-90celsius, then we made a pressure test, without heating, it wont usually leak. Heat will expand cracks and then it will leak..
I have got personal experience in 4 blocks.. And 3 blocks need top hats..

So i recon that you heat it before you install it to you car..