Coolant level dropping , leak around cylinder head/gasket

Kovito

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Grady White 274 Volvo Penta kad44 Disel:

I noticed coolant level is dropping as well as a leak around the cylinder head cover and gasket.

How do I know if this is a bad gasket or cracked head? I can provide pics if needed. Thanks in advance.
 

DennisG01

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Pull the cover off and take a look. Hopefully you'll see that the gasket has failed. It should be easy to tell.

You should also be looking to see if the gasket has failed to the point where it is getting into the oil. How does the oil look? Has the level changed? Even if it hasn't changed, I would still recommend getting an oil analysis done - it's cheap to do.
 

Halfhitch

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Are you talking about an oil leak at the valve cover gasket or a water leak? It's not clear the way your first sentence is worded. I would assume that it is an oil leak at the gasket, which could be just a deteriorated gasket, lack of sufficient torque on cover bolts or deformation of the cover. To figure out if indeed there is communication of combustion gasses between the cylinders and the water jacket, just start the engine and with the heat exchanger cap removed pour water in till it is totally full to the brim. Continue running the engine and watch for air bubbles, all the while pouring more water in as it spills out. There may be air trapped in the system if it was very low before you start this so if there are a lot of air bubbles at first, just ignore that but after 5 minutes or so if bubbles continue to show as you run with the heat exchanger tank at the overflow state then there is combustion gasses getting into the water jacket either through a failed gasket or cracked head.

Be sure that you examine the coolant for contamination from the raw water side before you start looking for bubbles. I don't know what type of heat exchanger you have but they can have internal failures from corrosion and cause you to loose coolant while sitting. You can pressure test the exchanger easily to check its integrity.
 

suzukidave

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Grady White 274 Volvo Penta kad44 Disel:

I noticed coolant level is dropping as well as a leak around the cylinder head cover and gasket.

How do I know if this is a bad gasket or cracked head? I can provide pics if needed. Thanks in advance.

a photo of the leak would help.

the head gasket is between the head and block quite a bit lower down the side of the engine than the valve cover seam on top of the head where you describe a leak. the valve cover would not normally leak coolant but quite often seeps oil unrelated to coolant loss. depending on the coolant used, an external hot coolant leak produces a "crusty" looking residue with crystals in it that does not look much like oil although with a very small leak or a cold leak it is hard to tell.

if the leak is definitely the head gasket, you generally pull the head and inspect it for cracks. if you see none you can send it to a machine shop to be tested to confirm it is not cracked or take a chance and refit it with a new head gasket.