Head gasket or some other issue?

[SimonA]

Within 30 seconds of starting my diesel engine the coolant bubbles up and is pushed out of the coolant filler if I leave the cap off. With the cap on the coolant level drops fairly quickly. No mayo under the oil filler cap although the oil does look watery.

Engine is a BMC 1.5. Starts fine and runs ok other than the coolant issue and watery oil.

I tried putting a liquid gasket sealer (steel seal) in, the coolant started to circulate properly for a few minutes and then the bubbles and overflowing started again. I guess this might confirm the head gasket has blown?

 

[omega2]

Oil cooler?

 

[TQA]

These are the goto guys for that engine http://www.calcuttboats.com/engines.html

 

[volvopaul]

Within 30 seconds of starting my diesel engine the coolant bubbles up and is pushed out of the coolant filler if I leave the cap off. With the cap on the coolant level drops fairly quickly. No mayo under the oil filler cap although the oil does look watery.

Engine is a BMC 1.5. Starts fine and runs ok other than the coolant issue and watery oil.

I tried putting a liquid gasket sealer (steel seal) in, the coolant started to circulate properly for a few minutes and then the bubbles and overflowing started again. I guess this might confirm the head gasket has blown?

Buy a gas test kit to test fir combustion gas in the coolant, if it's literally 30 seconds it can only be the head gasket or a cracked head inside the combustion chambers with will mean a head repair.

 

[boatmike]

Agree with what others have said but these engines have a relatively small clearance between the water jacket and combustion chambers. What can happen is that corrosion of head and/or block causes water to track across and you won't solve the problem by just replacing the gasket. either the head or block must be skimmed and one way to solve the problem is to remove an equivalent depth of material so that 2 gaskets can be fitted to return the engine to the correct compression ratio. If it is just the head though you may find a good cylinder head in a scrapyard. There used to be a lot of them about!