347 Burning coolant (As in steam train amounts)

[lukep6470]

HI,

So about 6 weeks ago I broke down on the top of a small hill. There car was just warming up, I was doing 65 in 3rd with stuff all throttle then massive amounts of steam came out the exhaust. I pulled over immediately (Within 100m) and called a tow truck.

The first thing I found was the intake manifold and heads full of coolant. The intake manifold gasket had blown out. It was a procomp so I figured I was a victim of finest cheapest. This is all very easy to see with an ITB manifold.

I replaced the Promcomp gasket with a Steel core Felpro one (Also replace front seal and fix rad leak at the same time). I also replaced the oil. The motor started and ran fine for about 1.5mins then steam out the exhaust again. This time the inlet manifold is dry. I also had a milkshake in the sump.

OK has to head gasket that caused the manifold gasket to blow right? So I replaced the stock style Felpro head gasket with the HiPo 1011-2 gasket, replaced the head bolts while I was at it and adjusted the rockers as well. As well as another set of steel core intake manifold gaskets were talking $100s spent now. I couldn't see anything obvious wrong with the old gaskets I pulled off but hey maybe I missed something.

Just ran it up again and the same deal. As soon as the motor gets a little heat in it massive amounts of steam out the exhaust and water in the sump. The engine sounds fine while it is doing this, no knocks or rattles.

Any ideas?

I'm starting to think the "best of everything" engine has a nautical future!!!

[Dwayne]

Did you accidentally fill it up with hydrogen instead of petrol?

[lukep6470]

Well it is in QLD

[hybrid]

Since you have replaced all the gaskets, I would be checking the heads/manifold for cracks.
What you could do is make up some blocking devices for the engine radiator hose inlet/outlet.
In the top blocking device, put a tyre valve in it.
Then you can pressurise the whole system with a compressor/bike pump etc and you might be able to find where the leak is without filling everything with water.

You can also do it with a special radiator pressure test tool thing if you want to leave the radiator in place.

[lukep6470]

I think you right about the head I just don't want to believe it!!! It must be a crack in the combustion chamber. I had a bit of a look but couldn't see anything with all the mess from burnt coolant.

I like the sound of the pressure test. I'll work out how to get a valve installed. Maybe the radiator cap?

The manifold looked good, I pulled the cover of the plenum and looked through all of it and couldn't see anything. There is only a waterjacket at the front and a small elbow style jacket at the rear.

[Nuts]

Check to make sure the gap between the manifold and heads is the same at the bottom of manifold as it is at the top. Also pull the plugs and see where it's wet. might help locate the source.

[lukep6470]

I looked down the throat of each TB while the motor was still hot and nothing appeared to be coming from the intake.

I found a cooling system pressure test kit on ebay for $58 so ordered!!!

[Nuts]

What heads and manifold are you using? Really sounds like a leak between a coolant passage and inlet or exhaust. Plugs should tell you the story.

[lukep6470]

Hi, Brodix heads and no-name Weber manifold. Everything has about 2000Kms on it before the failure.

[Shaunp]

Pull the plugs out first thing to do see which ones are wet or have no carbon most like a manifold leak

[hybrid]

Everything has about 2000Kms on it before the failure.

This is what steered me away from gaskets etc.
Unless something has warped recently, it shouldn't be a manifold sealing issue.

[lukep6470]

I really hope it is the manifold. As it is burning the coolant all the plugs look dry and the same so no joy there.

I hope doing the pressure test with the engine cold will make it more obvious.

[hybrid]

Once you have some pressure in the system, you could potentially put a piece of hose down each runner and hold it to your ear to see if you can hear a hiss in a particular runner.
Do you at least know which bank it's coming from?

I'm forgetting you have individual throttle bodies, so a crack in one cylinder shouldn't affect any of the others as there is no path between them.
I've changed my mind now... I'm leaning towards the intake not sealing properly. I can't see any other way for it to affect multiple cylinders and also fill the sump.

A leaking gasket will fill the valley with coolant and it will drain into the sump.

[Shaunp]

If it is the intake and I bet it is , felpro make several gasket thickness in 1250 &1262 sizes i also assume you are not using the cork end pieces, first way to make them leak and not pull down correctly, Can I assume you are putting RTV around the water jackets on the intake Gasket as well?

I stick the gaskets to the heads with contact glue to hold them in place so they cant drop and put RTV around the water passages, never had an issue.

[lukep6470]

HI,

Yep rtv around the water holes and at the ends of the manifold as usual. I can see the gasket and manifold to head pretty easily so you can tell if the gasket dropped or not.

Waiting on pressure doover with baited breath.