I've been having overheating
problems with my engine
, in an attempt to resolve the issue I have stripped off the heat exchanger
pump, thermostat housing and reservoir end caps to inspect the the engine
The thermostat housing and expansion tank are made from aluminum
, the expansion tank surrounds the exhaust
manifold and is an integral unit.
When I removed the end cover from the expansion tank (has the exhaust elbow
attached) to inspect the inside and make sure it wasn't blocked I found that the internal aluminum
casting seems to be badly corroded around the exhaust section. The exhaust elbow
seems to be a home made affair put together with various mild steel
pipe fittings welded together, the external cover also has pitting around the the elbow.
The thermostat housing has also suffered badly from corrosion
with a pin hole developing when I removed it.
Ive always understood that aluminum and steel
should not be connected together, there should be a insulating layer between them.
The zinc in the water
side of the reservoir was broken off from the fitting but seems hardly worn.
I have two questions:-
1) As the company that marinised the engine are no longer in business and I cant get a new one, can the reservoir/exhaust manifold be repaired and how?
2) What would be causing the corrosion