engine coolant flow

[roberttigar]

Which way dose the coolant water flow?
From the pump thru the oil cooler, heat exchanger the exhaust manifold and then the block?
Or, from the pump to the block, the exhaust manifold, the heat exchanger, the oil cooler and back to the expansion tank?

Bob

[DougR]

The coolant flow can differ somewhat between different brands of engine, but a typical flow is as follows:
-From the circulation pump into the block, down the length of the block and up into the cylinder head. From the head there are usually two options:
1. Out of the head and into the exhaust manifold, and from the exhaust manifold thru the thermostat housing and to the heat exchanger. Or
2. Out of the head via the thermostat housing and then into the exhaust manifold and then to the heat exchanger.

Sometimes the return coolant from the heat exchanger goes thru the oil cooler before returning to the circ pump. Sometimes a small amount of coolant is diverted from the block to the oil cooler, and sometimes the oil cooler is cooled by sea water and it's not in the coolant circuit at all.

The above are probably the more common flow paths, but there are always exceptions to the rule.....

DougR

[GILow]

My engine (Nissan) is as DougR described in option 2.

Edit: by oil cooler I assume you mean engine oil? My transmission oil is cooled by a separate raw water heat exchanger which is actually between the sea water strainer and the raw water pump. This struck me as odd but it is how it has always been done by the company that marinised my engine.