Hah...what a day ! Today was a whole summary of Looper Life in one day ! Both the Good and the Bad !
Wife and I indulged a bit today by heading over to Patti's 1880 Settlement Restaurant. If you are ever in this area....GO ! There were a couple of posters earlier in this thread who were quite high on the place as well as tons of great reviews and word of mouth up here. It exceeded expectations.
Its a mix of Southern homestyle and Kentucky Mountain with just a bit of kitsch thrown in. It has big walking gardens and outdoor shops as well as the expansive main dining with individually themed small rooms. The menu has catfish and pork chops and steaks and HUGE pies !!! The food is excellent and the portions are immense ! Wife and I are Stuffed and we brought home at least three more meals of leftovers onboard ! Highly recommended ! One of our dining highlights on the entire Loop !
So we left Patti's in our rental golf cart to head back to the marina....good thing we had a cart cuz we would have needed wheelbarrows to get back. Such a great meal !
I had already planned to work on the boat this afternoon doing a couple things including swapping out the current impeller.
An impeller, if you don't know, is a rotating flexible bladed "fan" type of thing made of neoprene or nitrile that sits inside a pump housing. It gets compressed on one side as it spins and expands on the other side. In so doing it produces suction/pumping action which pulls raw water in from an opening on the bottom of the hull and circulates it to take heat away from the engine oil and other engine parts before being injected into the exhaust piping to both muffle and cool the exhaust gasses. Its a crucial part of the cooling system.
Mr Smartypants ( me ! ) always likes to quote "The Best time to change an impeller is 10 minutes before it fails !"......today I failed ! I messed up !
My engine usually runs at a temperature of 174 to 176 and is rock solid in that tendency. The past few travel days I noted a 2 to 5 degree increase gradually over a 6 hour day. I keep detailed records and although 2 or 4 degrees is not much, it bugged me.
I know 175 is waaay below the danger point for a diesel....and know a lot of others run at 180 or 190 or even higher....but I know this engine and for several thousand hours of run time 175 is its sweet spot.
So I pulled the raw water GROCO strainers and removed 8 or 10 small mussel shells and a bit of weed....no biggie. I added 1/2 pint additional coolant. I topped off the oil. I reached overboard and made sure the seacock opening was not obstructed. Still ran a couple degrees warm.
I got to thinking ....the water Temps here in Kentucky are several degrees warmer than the water in Lake Michigan was. Maybe that accounts for the small rise ?
Then again...I had the time...why not just replace the impeller and see if that helps.
I settled in for the usual 30 to 45 minute job to swap out an impeller. Closed the seacock so as not to sink the boat.....cracked the 6 bolts on the housing....drained the water from the pump casing and took off the cover and found.......shreds !!!!
The impeller was trashed ! Ripped up into pieces and only 3 vanes remaining intact ! Not at all what I expected !
The wife and I have very specific routines for engine start up. We BOTH check for raw water flow out the exhaust at two different points in the start routine. We have been seeing flow each day. How in the world this impeller was still managing to pump totally surprises me !
So pulling the mangled impeller out was no chore since it no longer fit tightly in the housing....but THAT is NOT the problem !
The raw water pump sits UPSTREAM/BEFORE the coolant water enters the Heat Exchanger, the Oil Cooler, all the rest of the engine and then the exhaust ! All those shredded bits and bobs have to be found and accounted for in a tedious jigsaw impeller puzzle or else you run the very real risk of a bit blocking a passage and causing a serious catastrophic overheating situation !
So....nothing else to do but.....explore, disassemble, fish, trace and follow the raw water coolant path until all bits are accounted for. Not at all fun. Not at all what I expected today !
You know where I said earlier that each day Looping is like a surprise Pop Quiz....well this is a good example. I thought I was good to go today...and now I have a disassembled engine.
Fast forward.... eventually found what I think is the complete bunch of bits....reconstruction of the shredded impeller looks complete. Put the engine back together.
Now its time to restart and check to make sure I got her all buttoned back up correctly and no leaks....as well as checking to see if she runs cool.....seems I am back to 174 this evening.
Lessons learned......when you notice small changes from what is normal...there is a reason for it. Find it.
Don't expect 400 hours from an impeller here forward.
Continue to keep 3 spares of most of the crucial parts onboard because you really never know.
Looping has Good and Bad...its an Adventure not a Vacation.
Sitting this evening now with a Bourbon and looking over charts for anchorages for the next two nights....then holing up in a marina on Sunday for a few days while the COLD comes sweeping in up here.
What a day !