Perkins 4.108 Overheating

[freelandken]

Since there is no way of sugarcoating my major blunder, here are the facts.
I ran the engine without water circulating, for 20-30 minutes before overheating alerted me to the problem. I immediately switched the valve so that water would circulate. The engine cooled down somewhat but lost probably all coolant. Since that time I have replaced the thermostat, although it seemed to be ok. The impeller was destroyed and changed. I removed the hose to the rear of the engine where the remaining pieces of impeller were residing and sucked out a good many pieces with my shop vac. Replaced coolant. Checked oil. No leaks that I can see. However, the engine is still overheating (210+-) Any ideas? The engine has only 1500+ hours.

[FamilyVan]

Last overheating problem I had with a Perkins 4.108 turned out to be nothing more than a loose belt on the water pump. Its probably worth checking out.

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[model 10]

Does it loose water before it overheats? If you shut it down before the cap blows, is all the water till there? Before it gets to hot, are there bubbles in the expansion tank?

[Wotname]

Originally Posted by freelandken

Since there is no way of sugarcoating my major blunder, here are the facts.
I ran the engine without water circulating, for 20-30 minutes before overheating alerted me to the problem. I immediately switched the valve so that water would circulate. The engine cooled down somewhat but lost probably all coolant. Since that time I have replaced the thermostat, although it seemed to be ok. The impeller was destroyed and changed. I removed the hose to the rear of the engine where the remaining pieces of impeller were residing and sucked out a good many pieces with my shop vac. Replaced coolant. Checked oil. No leaks that I can see. However, the engine is still overheating (210+-) Any ideas? The engine has only 1500+ hours.

First step is always checking the obvious
Did you get all the pieces out, especially the tiny ones that maybe went further into you raw water circuit. Can you account for every last piece?

Apart from physically looking at the recovered pieces, you can weigh them along with the remaining impeller body and compare weight to a new impeller. Of course there will be some difference but the amount of difference may be telling.

Engine is not normally badly damaged by a single short overheat problem so there is a fair chance that your heat exchanger is still blocked somewhere.

Good luck and let's hope it is a simple fix!

[freelandken]

Thanks GUY, I don't have answers to those questions yet. I will check on them. Away from the boat for couple of days. Thank you.

[freelandken]

Thanks Wotname,
Don't have the equipment to weigh the pieces. Did actually think about that. What would I have to take apart to find every last piece of impeller?

[Wotname]

Originally Posted by freelandken

Thanks Wotname,

Don't have the equipment to weigh the pieces. Did actually think about that. What would I have to take apart to find every last piece of impeller?

If pushed, you might make up a simple beam balance with whatever stuff you have onboard

Try back flushing the heat exchanger with some force. Often but not always, the tubes in the heat exchanger are the smallest part of the system so stuff lodges there first.

However it is wise to check each and every part of the raw water circuit

[freelandken]

Ok Wotname, will see if I can do that. Thanks again.

[DeepFrz]

I would recommend you dismantle your heat exchanger and clean it thoroughly. Also your water injection elbow where the water mixes with the exhaust. Make sure non of the passages are blocked. Some of the impeller bits you got out may have been from previous impellers.