Hi all. My cross flow is loosing water at a rate of about half a pint to 50 miles. No external leaks, No water in oil or oil in water. I took a lot of metal out of the ports when I worked the head and none of the faces were planed, It only seems to loose water when its running. No water is coming out of the header tank cap & the system isn’t over pressurising . What I want is for someone to tell me it can be something other than I’ve gone to far on the ports. I know the area around the water jacket on the twin choke weber manifold was a bit corroded, has anyone lost coolant into the inlet ports there

Get the cooling system pressure tested for leaks would be a good start, then perhaps a head gasket test. A 4 gas exhaust tester would show up any hydrocarbons in the cooling system but DO NOT pick up any coolant. It might be worth just letting the coolant find it's own level, mine losses a bit if I fill to the maximum but even on long runs never drops below the minimum. If you suspect corrosion on the inlet manifold gasket surface take it off and clean it up on a surface plate or get it skimmed.Are you using a pipe between the manifold and the water pump? (heater pipe) I've heard of problems when one isn't used

Hi Mel. Thanks for the input, I did have a pipe between the manifold & base of the header tank, Header tank is the highest point, I’ve fitted a fiesta thermostat housing with a bleed off pipe going to the top of the header tank. When I noticed I had a problem I tried moving the header tank pipe to the water pump with intention of T ing in to the manifold but at the mo the manefold is just blanked off. One of the main reasons for fitting the cross flow apart from nostalgia was ease of maintenance so I might just pull the head and have a look. I always wanted to build a 1600 in the end and use this head (I spent a lot of time on it) so the head is important. If one of the ports has gone porous I don’t know if it would be visible or if it would have to be crack tested

I would have thought that any leaks in the ports would have shown up as white exhaust smoke and possibly a misfire? What pressure rating cap do you have ?

A very small coolant leak when up to pressure and temperature won't show up because the coolant flashes off into steam, steam is invisible.

Whats required is a presure 1.5 bar test when cold, however before doing that you can examine the water pump seam for signs of leakage.

am i right in thinking you have a header tank system? how full is the tank when you start (before any of the coolant loss?)

Thank you all for you input, I have a 15 psi cap & a 82 thermostat, It does idle like a pile of poo but it has got a 234 cam & once on song it runs well, gives a bit of condensation from exhaust when cold but seems clear when hot.
I’ll have to see if I can scrounge a pressure tester or knock one up, am I looking for water or a drop in pressure or both.
The header tank is half filled when I start, I have put a catch tray under the overflow & found 1 or 2 drips only, but I guess it could go in steam.
If I can get someone to test & detect hydrocarbons in the cooing system I guess that can only come from the head gasket.

If you are using a pressure tester look for water first , don't forget to check for drips from the bell housing, I can't remember if the Xflow has a core plug on the rear of the block behind the flywheel but it won't do any harm to check. Another way of testing for leaks is to put a dye in the cooling system that shows up under U.V light. I might ?? be able to help with the dye but my UV lamp is faulty. I have a pressure tester somewhere if I can find it that may fit depending on what type of cap you have. Will have a look tomorrow if I get a chance

Found my pressure tester if you want to borrow it John.

Thanks Mel. I could probably come over for a blat to borrow it if its ok at the week end, Don’t know where to find you mind. Maybe you could U2U me you’re address & phone no & I’ll give you a bell I leave. Ta john.

You have u2u