W50 Overheating Mystery

ScottC · **Joined:** 02 Jan 2011 15:51 **Posts:** 53

I ordered the new pump with the improved (smaller) pulley to increase the flow. There is also a 6 inch oil cooler in the line going to the fresh water pump with sea water going thru the oil passages then to the exchanger (as advised by 2 mechanics who work on Westerbekes). I am exercising a great deal of trust, but this is the last straw. If this doesn't work...Behold, the power of BETA (Please let this work!). Oh, and a new thermostat just in case.

puffcard · **Posted:** 18 Jul 2012 08:31

ScottC, I know I said this before, but do the white vinegar flush on the warm motor. I done it several times and have seen a improvement each time. I was amazed at the calcium and scaling that comes out the exhaust each times. This scaling sets up in the heat exchanger and slows the heat transfer. The cleaning works like how people clean coffee pots with vinegar. It also quick and easy DYI project. All you is a plastic bucket or container, a fitting for attaching the 1/2" hose and a 1/2 hose nipple and 2gal wht vinegar. Remember mechanics make money replacing parts.

jvoelxen · **Joined:** 21 Oct 2006 15:36 **Posts:** 268

Scott-

Just a followup to your tachometer issue (i.e., reads lower than actual at higher rpms). I checked mine this weekend. It reads correctly at 1000 rpm and 2300 rpm, so you do have an issue. Not sure that it's related to your overheating problem. As I understand it, the tach takes its input for the AC terminals on the alternator, which is a direct measurement of the alternator's rpm. If you confirmed that the engine has higher rpm than the tach, and the tach senses alternator rpm, which is directly proportional to engine rpm, unless you have a lot of belt slippage, I would guess this problem resides in the tach.

Good luck with your other fixes. Please let us know the outcome.

Jim

ScottC · **Joined:** 02 Jan 2011 15:51 **Posts:** 53

So far the outcomes are a lighter wallet counterbalanced only by the growing sense of frustration. If nothing else, my new Dometic Cold Machine refrigeration runs like a charm. I am going to try the white vinegar de-scaling on Wednesday, and the new parts should be installed early next week. If none of that works, it will be a new engine. I really hope it doesn't come to that for another few years.

Ardea · **Joined:** 19 Mar 2007 16:40 **Posts:** 195

Just a thought...what kind of shape is your coolant pump in?

Down2TheC · **Posted:** 30 Jul 2012 00:59

Something I found today made me think of your cooling issue. I had the pump out for an impeller change rather than doing it in place. With it open in front of me I saw rubber in the pump outlet. 6 impeller vanes were jammed in that 90 degree bend. I could see a dam of interlaced rubber allowing slow flow by but with increased flow becoming more restrictive as it gets pushed against the opening. If you take your pump out (two bolts and two hoses... pretty quick) you can shine a light in the outlet and you should see pipe at the bend. If you pop the impeller out you should be able to stick a screwdriver in the outlet and see it down the small outlet of the pump body to make sure you have a clear path. Seems basic, but judging from the six vanes I pulled out today, they've been there a long time. Worth a look if the mechanic already cleared your heat exchanger.

Failing that, I'd go to each step you can isolate a part of the system. Run the engine with the pump outlet disconnected and see if you get the same reduction when at high revs. Then go down stream test by test until you find the first connection that shows reduced flow and you'll have isolated where the blockage is. Might be messy and fill the bilge, but it's only a couple runs. pump outlet, heat x inlet, heatx outlet, oil cooler inlet/outlet, siphon valve in/out, and finally the inlet to the muffler. You might want to consider the heat x and the oil cooler as a unit for the first pass. That little hose is an unlikely spot for blockage and looks tough to remove.

Just spitballin'
Cool

ScottC · **Joined:** 02 Jan 2011 15:51 **Posts:** 53

I'm upgrading the pump this week, so I know it will start out without any vanes in there. If it still overheats after this round of repairs, I'm going to throw a hail Mary with the step by step analysis. However, I've done most of the examination already in bits and pieces so I don't have high hopes for that. I should know something definitive by Saturday.

ScottC · **Joined:** 02 Jan 2011 15:51 **Posts:** 53

It...is...ALIVE!!! The overheating saga is over (for now)! Granted, I don't necessarily want to see the invoice for this latest round of repairs, but it should be less than 1/15th the cost of a new engine! So the fix seemed to be a new (larger capacity) raw water pump, new thermostat, new oil cooler, new secondary coolant cooler, new placement and new temperature sender, and a relocated hot water feed line to the top of the cylindar head (to eliminate chance of an air lock on the suction side of the coolant loop).

I warmed up slowly, then ran her hard for well over four hours. The thermal gun thermometer never broke 185 on any spot of the engine.

I couldn't be happier with the results.

Tortuga's Lie · **Joined:** 27 Oct 2006 10:32 **Posts:** 827

This means you'll be able to sit back and enjoy the rest of the summer....with a clod beverage at the end of a wonderful sail! Cheers

T397 · **Posted:** 06 Aug 2012 11:03

Congrats!

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W50 Overheating Mystery

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