Antifreeze. coolant in forward carburetor- update 9/24/23 WHT is the leak?

Well It just gets better every day!! See previous leak thread

The pressure tester didn’t work…couldn’t seal. so I dialed down the compressor air deliver gauge and gently pressurized through the overflow hose. Found a leak at heater valve. fixed that…maybe.

Then I notice water dripping out of the front carburettor. This is why people put these things in the basement for 30 years.

Anyway what is up with this?

Could be the inlet manifold is leaking coolant which means a cylinder could have filled up with fluid in it.
I would suggest to get the spark plugs out and check the cylinders asap

should I drain the coolant…again?

Hi Bill,

If it were me, I would look inside each cylinder and see if any have coolant in them asap. Take plugs out and look in with a flashlight or a scope. If the piston is too deep, use a long chopstick as a dipstick to check.

If any do, the head needs to come off asap and the water in the cylinder cleaned out or cylinder rust will occur etc… and it will be expensive if not done.

If no coolant in cylinders, next step is to find the source of the coolant leak which is likely the intake manifold leaking at a gasket, or a crack in the manifold. This means drain the coolant to below the level of manifold, take off the carbs and manifolds, inspect where leaks may have been, get new gaskets, clean up surface and reassemble without carbs on. Then pressure test coolant system without raising coolant level to where it should be. It will take longer to pump up air pressure, but the idea is to see if air pressure holds( in case you still have a leak and it needs to come apart again.) I have never been in favour of the metal gaskets,… And I always use a sealant (very sparsely) on inlet manifold gaskets. If you use a metal gasket, the Permatex hitack stuff would be what I suggest to use. I would do a very thin circle of Permatex hi tack around each air intake port and each water coolant passage (on both sides of gasket.) I did this on my paper intake manifold gasket. It never hardens and is fuel and waterproof.


charging a scope as we speak.

I might see a drop or two on the #6 (forward) piston. #2 is too far down to see. If the water went into a cylinder… wouldn’t it just leak past the rings into the crank case?

And how do you tell if you have water in the CC when the oil is brand new?

If I have to take that head off, I am killing myself first. I don’t even think I can make it past the carbs.

Just took another look with a small light I remembered I had. I see moisture on the piston tops of 6 and 5 but it’s looks like the amount of water you would see with condensation.

Edit: just looked again…can’t be sure the liquid I see is not oil I put into the cylinders to prevent rusting

Pull the plugs…disconnect the fuel pump coil etc…put some rags over the plug holes…spin the engine over a few times…it will throw out any moisture in the bores…spray in a mist of oil…check whats on the dipstick…or just drain the oil if you suspect coolant has drained into it…change oil filter…pull of inlet manifold and seal it…Steve

Draining the radiator right now, so there wont be additional leak in the meanwhile.

Don’t want to spin the motor because it has never been turned and the engine builder said when I had it ready to start he would come over and pre oil it and HE would start it.

I was sooooooooo close.

If he did the rebuilding of the engine and your warranty is pursuant upon him doing that, I would make sure he is involved in checking to make sure about the water leaks.

There is a step that you should take but I’m not sure you are going to want to do it without him there. This is news to me, and makes things a whole lot more wrinkly that it was before.

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News to me. It was always drummed into me not to use gasket stuff on the intake and ex manifold gaskets. This must be a ******* jaguar thing

Ok Bill…get a compressed air line and blow out any coolant in the bores…then a few squirtes of oil wd40 or similar spray…sealant on inlet manifold around coant channels…Steve

120 lllbs psi. Blew into the cylinders and got water out of the number two carb this time. I am draining the radiator to lower the water level.

Isn’t there some kind of thing with these cars about the water passages being different between 3.8 and 4.2. And is there anyway say, plugging the wrong water holes or using the wrong head gasket could do this?

Hi Bill, I would now spray some WD40 on the cylinders. The “WD” stands for water displacement, will help any “flash” rusting of the bores, while you sort this out.
Edit: just noticed that Steve said similar.

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this is Number 6 cyl. (forward #1 in American speak).

Just happen to have a new supply of wd 40 . spritzing now

edit". those little marks I thought were droplets look like knicks in the Al. piston

I’d install a Cometic (sp?) intake gasket. It’s just better at sealing and you stand a chance of removing the intake without the use of explosives or heavy equipment should the need arise later.

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So far, the best advice you’ve gotten used to pull all the plugs, go ahead and crank it over (you’re not gonna do any harm), that wil expell any liquid, drain the coolant, and then spray the cylinders with WD-40.

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Moisture in your oil? Here’s a cheap trick. Use an ordinary blowtorch & heat an area on your garage floor. Ideally you want a temperature well above boiling point. Put a few drops of your cc oil on the heated floor. Any bubbles forming indicate water/antifreeze in your cc.

Don’t despair Bill you’ve probably got an intake leak , minor set back a bit of water is nothing. Follow the advise get it out and carry on
but make sure it’s evenly torqued before you remove it. Maybe back off the nuts and re torq from the centre out in a circular pattern as a last gasp Pressure test your intake manifold before you reinstall it

where would I get one for the Jag?