Water leak - exhaust manifold (Volvo Penta MD6A)

[Usangi]

Hi - in an attempt to work out why my old Volvo Penta MD6A is overheating I removed the exhaust manifold and cleared out some blocked channels. Unfortunately after cleaning it up (as best as I could) and fitting a new gasket, its leaking at the top join. Also - water flow doesn't seem to be much improved, which is a shame.

Any ideas what I need to do? Perhaps add some gasket paste? Also, I have torqued it correctly, but I'm wondering if I could just tighten it a little more to see if that might stop the leak.

 

[VicS]

If the total water flow is poor have you checked the inlet and strainer
Have you fitted a new impeller and checked the pump for wear
Have you checked the hoses
Have you checked that the injectionpoint into the exhaust is not restricted

I would remake the leaking joint , making sure the joint faces are clean and undamaged.

 

[Usangi]

If the total water flow is poor have you checked the inlet and strainer
Have you fitted a new impeller and checked the pump for wear
Have you checked the hoses
Have you checked that the injectionpoint into the exhaust is not restricted

I would remake the leaking joint , making sure the joint faces are clean and undamaged.

Yes, checked the inlet and strainer, and fitted a new impeller (plus turned around the cover which had a small groove worn into it). Also checked hoses and the injection point into the exhaust.

It's worth saying that the exhaust manifold (and also the elbow) have seen better days. I tried to clean the mating surfaces as well as I could, although I could probably have another go. Link to photos of what I've done are below. It took quite a lot of effort and can't seem to do much better, although I could get a roloc disc for the dremel. On link there is also a video of the water flow from the exhaust.

https://imgur.com/a/VT0l5ZK