Perkins 4.108 Overheating Problems

[johnar]

Tom yes I have normal flow coming out the exhaust,

Dutch

[cbat]

Thought I would post the fix to my overheating problem. All things pointed to a faulty fresh-water pump (recall that the raw water side was good, no apparent blockages in the fresh water system). So before I called in the cavalry I thought I would pull the fresh-water pump. I knew within a couple of minutes that that was the problem as once the alternator belt was off, the pump pulley spun with zero friction. It just free-wheeled!

Pulled the pump and the shaft had sheared just inside impeller housing. There was no indication of pump failure wrt to leaking coolant or oil. Only symptom was no fresh water flow. I ordered a new pump from the local Perkins supplier, pulled the old pulley, pressed it on the new pump. Once installed and the system bled (including the plugs on the top of the cylinder block) all was good!

In retrospect, I could/should have figured this out very quickly. As is always the case, when there's a sudden and catastrophic overheating issue it's most likely a component failure. First thing to check is a blown hose, closed sea-cock,etc. The second is the raw water circuit. Once that is eliminated, it's likely not a blockage in the fresh-water system as these system is closed and most likely any blockage would be partial in nature and build up over time. This leaves the thermostat and raw-water pump. I could have easily pulled the alternator belt before removing the thermostat and tried to spin the pulley. That would have told me right away what the problem was.

Having said all that, I did learn a ton. Especially from all the other problems that others had solved in different ways.

Thanks everyone for helping out! Much appreciated

[mveerman]

This whole thread was amazing, so thanks. I recently went through a similar problem after removing the header tank/exhaust manifold in order to get the fuel injection out for a rebuild. My solution was unique and not one I've read (or just missed).

When I put it all back together, and got the engine started, it would quickly overheat. Prior to doing this work, she'd run at at a steady 170 degrees. We had, what appeared to be, sufficient raw-water flow rate. As soon as I ruled out EVERYTHING else mentioned in this thread (2 days later) and was out of ideas, I started to look more closely at the raw water system again. KISS people!! It turned out to be an un-centered installation of the tube stack. The tube stack wasn't seated far enough into the rear boot which meant the front boot was on too tight. There was probably 1/8" of room for water to flow in front and an 1" in back. I only had to squeeze the boots to realize the problem. I quickly drained the header tank, re-positioned the tube stack correctly, topped off the coolant, and voila! Engine is back to running perfectly.

I hope this helps some future someone. Thanks again for all the other invaluable advice.

[nolakennedys]

Fresh water pump was always my first guess, just read the first page of the thread. Glad you got it sorted!