Perkins 4108 anti freeze leak

[CalicoJack]

Help! This is driving me crazy!
Back in the spring I had to remove the Serk heat exchanger to replace the metal fuel pipe from the filter round to the injection pump. On replacement I discovered that I had a leak on the closed (antifreeze) system. The heat exchanger was removed again and professionally repaired and although this did reduce the amount of antifreeze that was being lost it did not stop it. The heat exchanger was removed yet again and pressure tested, it was sound. I’m loosing about half a litre in two hours motoring. I think that I have done the obvious stuff, hose clamps have been tightened and I have peered at the engine from as many angles as I can, but I can’t see anything. I did find that one of the drain taps was wet, and I have replaced it by blanking it off. The floor of the engine compartment appears to be quite dry, but not bone dry.

The engine runs very well, it starts every time; this morning it started first time having stood for a fortnight, this despite the fact that there was ice on the deck. The oil level remains constant and there is no “mayonnaise “ in the rocker cover.

Has anyone any thoughts?

 

[Old Harry]

a leak between the indirect / sealed system ????

 

[flyingskipper]

Hi,
It might be worth checking the elbow on the water cooled exhaust manifold. They can corrode from the inside, if the walls are compromised antifreeze will leak out with the exhaust.
Just a thought.

Andrew.

 

[RichardS]

Assuming that you're using coloured antifreeze, then 1/2 litre in the bilges/sump should be obvious unless it's being pumped overboard. It should be reasonably obvious where it's coming from due to the splashes it would leave.

If it's not in the bilges and not in the oil sump (the level would be climbing up the dipstick) then it must be going out with the cooling seawater or going out through the cylinders. The latter seems highly unlikely as the engine is running well.

Is there any trace of colour in the exhaust cooling water? Collect it in a glass bottle and have a close look.

Richard

 

[coopec]

There are a number of different versions of the 4 108 Perkins marine diesel. Mine is this one here



I found a slight leak under the header tank and had to remove it and have it welded upi

 

[rogerthebodger]

Get a radiator pressure test cap and then you can pressure test the whole system and find the leak.