The Triumph Dolomite Club - Discussion Forum

At this angle there was no evidence of any leak along the cylinder head joint so it does look like the water was running along the joint and pooling on top of the block. However there is a definite pool between the cylinder head and the water pump. Its very difficult to see in that area. This could be the cylinder head or hopefully the water pump gasket.

I plan to remove the inlet manifold to gain access and get a better look. Once I have the manifold off is there anyway to test the cylinder head joint.

Not sure if it's relevant here, but in my experience the inlet manifold gaskets currently supplied are WAY too thick - meaning that the o-ring on the inlet manifold doesn't seal correctly (I'm talking about my own experience on an 1850, so as I say, may not be relevant)
1.65mm (uncompressed) for new vs 0.55mm for NOS gaskets.
I appreciate that the new ones are a different material and might compress more once fitted, but they made getting the manifold o-ring to seal pretty much impossible.

The subject of the bypass tube has been comprehensively covered recently in the "Project PFJ is baaack!" thread in the resto section.

Turns out that pre 74, the tube can only be removed by taking the manifold off, after that it could be removed upward through the stat housing as shown in the manual. There was also an early tube design that, like the factory plug tubes, was rubber sheathed steel and therefore "one time use only". This tube is NLA and the modern ones with separate O rings are the norm.

I'm normally reluctant to remove the manifold if I don't HAVE to (it's a pig to seal the water gallery as has been said) and have used various methods to pull the tube out, most successful has been an old thread tap that just about grips inside the tube, pulled up with a mole grip.

But in your case I highly suspect that the manifold gasket is leaking around the water gallery which is directly above the pump housing and a leak here can often be mistaken for a bypass tube leak. In your shoes, i'd replace both the manifold gasket AND the bypass O rings for a clean sweep. I also use a bead of Silicone sealer just around the water gallery area of the manifold gasket, then i've not needed to get the manifold skimmed. Of course if the manifold mating face is badly eaten by corrosion (Which I HAVE seen) you'd have to rethink.

Steve

Any advice on the best gasket to use and where to get it.

This looks like it could be the source of the leak.

Any advice on the best gasket to use and where to get it.

The manifold appears to be flat when inspecting with a straight edge. Hopefully I can get it to seal without skimming it. Plan B.