grantmc 59 Posted July 27, 2013 Share Posted July 27, 2013 What are your thoughts on shutting down the water and let motor run for a few seconds prior to turning off motor? Have just had a new engine installed (has a heat exchanger). So I wish to maintain good practice. I understand the obvious like regular oil change, filer replacement etc. Thanks Link to post Share on other sites
Guest Posted July 27, 2013 Share Posted July 27, 2013 Bad idea. leads to deterioration in the impeller, intake hoses and exhaust hose. Engine manufacturers would specify this technique if it was necessary. They spend shed loads of money in R&D etc. just to have dockside "specialists" (not you but the person who told you) say they got it all wrong. Link to post Share on other sites
wheels 544 Posted July 27, 2013 Share Posted July 27, 2013 What PW say's, but I am wondering what your trying to achieve?? Link to post Share on other sites
Kiteroa 8 Posted July 28, 2013 Share Posted July 28, 2013 My old man has a good system on his power boat. He's installed a bypass valve on the engine inlet pipe so when he's back in the marina he can shut off the salt inlet, connect a hose on the transom, and run a fresh rinse through the engine. Link to post Share on other sites
Guest Posted July 28, 2013 Share Posted July 28, 2013 Just make sure the engine is running if you do this. I've seen major ugliness with this method. Link to post Share on other sites
wheels 544 Posted July 28, 2013 Share Posted July 28, 2013 To me it is a complexity that as PW says, can easily become a major stuff up. I don't see any benefit,or at least any benefit that would make the complexity worth the risk. Link to post Share on other sites
sealegs 0 Posted July 30, 2013 Share Posted July 30, 2013 My old man has a good system on his power boat. He's installed a bypass valve on the engine inlet pipe so when he's back in the marina he can shut off the salt inlet, connect a hose on the transom, and run a fresh rinse through the engine. I fitted a 3 way bypass on my salt water inlet as well last summer. So when I shut the boat down for a long period like winter I just connect the fresh water hose already connected to the 3rd outlet on the bypass to a fresh water source and start the motor for a couple of minutes until Im satisfied Ive flushed all traces of salt water out of the system ( 10-15 minutes).I then place the hose into a 20ltr drum of glycol solution and start the motor again to suck that up and turn off motor before all the glycol solution is sucked up. I leave that solution inside the motor for the duration of the winter tie up. When I started the motor again 3 days ago after almost 3 months I found the engine running much cooler than before and no longer heard the intermittent loud knock sound that the Volvo engine manual said was due to overheating. The overheating I suspected was due to the buildup of salt or whatever in the heat exchanger and the fresh water/glycol mixture removed that nicely. Even the engine coolant was lukewarm to the touch immediately after turning off the engine after 1hr running & finger testing it, Last summer it was way too hot to touch to even attempt a finger tip test and dangerous to open the coolant cap immediately. ( Wheels it was your comment way back on the effectiveness or lack thereof of "salt away" that gave me the idea of using fresh water to dissolve the salt and NOT the overpriced "salt away" . As you correctly stated Wheels " what dissolves salt" .....Fresh Water!) This good result means I would never have to remove the heat exchanger to clean it for any scale /salt buildup. So not a waste of time exercise at all but rather a time saving exercise..and beneficial for the engine cooling system by letting the fresh water remain inside the engine for a longer period with less hassle. It took me about 20 -30 minutes after a nice sail to complete the entire engine salt water flush before winter shut down. . Link to post Share on other sites
Guest Posted July 30, 2013 Share Posted July 30, 2013 Sealegs - your engine ran cool because it is F***ing freezing out there. Link to post Share on other sites
sealegs 0 Posted July 30, 2013 Share Posted July 30, 2013 Sealegs - your engine ran cool because it is F***ing freezing out there. yeah Ogre ... for you blokes down in auckland it would be freezing.. remember I live in the "winterless north". The sun is shining here. I was expecting rain today according to metservice but nothing happened. Sunshine all day long... Link to post Share on other sites
Guest Posted July 30, 2013 Share Posted July 30, 2013 When I started the motor again 3 days ago after almost 3 months I found the engine running much cooler than before and no longer heard the intermittent loud knock sound that the Volvo engine manual said was due to overheating. The overheating I suspected was due to the buildup of salt or whatever in the heat exchanger and the fresh water/glycol mixture removed that nicely. Even the engine coolant was lukewarm to the touch immediately after turning off the engine after 1hr running & finger testing it, Last summer it was way too hot to touch to even attempt a finger tip test and dangerous to open the coolant cap immediately. Maybe the conditions you just described are a symptom that... Oh f*ck it, fill your boots & second guess the engine manufacturer and winterise an engine in an area that doesn't actually get a winter. Link to post Share on other sites
too_tall 15 Posted July 30, 2013 Share Posted July 30, 2013 Even the engine coolant was lukewarm to the touch immediately after turning off the engine after 1hr running & finger testing it, Last summer it was way too hot to touch to even attempt a finger tip test and dangerous to open the coolant cap immediately. The water should be too hot to put your finger in. In fact, if its only likewarm, something is wrong. Check the engine thermostat - it sounds as if the thermostat has failed. The engine water temp should be somewhere around 80-95 degrees C when its been running for that long, specially if its been loaded. Think of your car - the heater should put out hot air. It only does this once the engine warms. Leave it idling for 10 minutes, its putting out hot air, even on a very cold day. This is because the radiator is actually thermostatically controlled - it only becomes part of the cooling circuit once the thermostat opens. It then will be detached once the thermostat closes if the water temp drops off sufficiently. ( which is a matter of several degrees ). Link to post Share on other sites
sealegs 0 Posted August 7, 2013 Share Posted August 7, 2013 The water should be too hot to put your finger in. In fact, if its only likewarm, something is wrong. Check the engine thermostat - it sounds as if the thermostat has failed. interesting.....So how do you check if the thermostat is faulty? (Engine manual states thermostat opens at 75 deg C & fully open at 87 deg C) Do I need to buy a new one, fit it and see if there is a different result (hotter) in coolant temperature to confirm previous one is faulty or is there another way before making a purchase? Link to post Share on other sites
grantmc 59 Posted August 7, 2013 Author Share Posted August 7, 2013 Very simple. Remove the thermostat and drop it into a some hot (near boiling) water. If it is working ok then it will open. Let it cool down for 10 minutes and it will shut. Unless it is relatively new then it will likely need a bit of a clean. Also they have a little by hole to allow the water to pass through when they are closed. The hole is about the size of a bullpoint pen nib. Check it is clean and clear. Link to post Share on other sites
Guest Posted August 7, 2013 Share Posted August 7, 2013 Yes or say "f*ck the environment". Link to post Share on other sites
grantmc 59 Posted August 7, 2013 Author Share Posted August 7, 2013 Yes or say "f*ck the environment". Daaa, what's your point? Link to post Share on other sites
Dude 0 Posted August 7, 2013 Share Posted August 7, 2013 Don't stuff around with it. Just buy a new one Dude!!! Why comporomise a yachts motor with a $10 part? Why people stuff around with small cost stuff only to bugger the big stuff is beyound me! I did it for years when i was a kid just to save $5 and waste hours of time! Don't be Tight arsed! over saftey! - - - Now thats a good quote! Link to post Share on other sites
Island Time 1,347 Posted August 7, 2013 Share Posted August 7, 2013 Its actually nearly as bad for an engine to run cold as it is hot. 90% of engine wear is when engine is cold. Always cold = heaps of wear! But outlet water temp is not always a good indicator of engine temp. Most modern engines are not directly salt water cooled. It is the salt water that (should) come out the exhaust. If the salt water only comes out warm, that may be because there is a large flow, or the heat exchanger is oversized, or simply that the engine is only lightly loaded. What is really important is the temp of the fresh, enclosed water cooling system. That's what your temp gauge reads - if fitted. By all means, check the thermostat as suggested. If it is closing properly, then the engine should get hotter till it opens, then sit at approx that temp regardless of the engine load. The thermostat opens and closes to regulate the temp of the engine. Excess heat = open, heat passed to heat exchanger. Excess cool, closes some more, temp rises... Your manual should give manufacturers running temp. If it is outside of that, ever, (other than warm up) it needs servicing. If you have no gauge, you can buy a laser thermometer on trade me for under 50 bucks. Great for the toolkit! Link to post Share on other sites
sealegs 0 Posted August 7, 2013 Share Posted August 7, 2013 Very simple. Remove the thermostat and drop it into a some hot (near boiling) water. If it is working ok then it will open. Let it cool down for 10 minutes and it will shut. Unless it is relatively new then it will likely need a bit of a clean. Also they have a little by hole to allow the water to pass through when they are closed. The hole is about the size of a bullpoint pen nib. Check it is clean and clear. thanks grantmc & Island time. good tips. will use that & check for any changes. Link to post Share on other sites
Guest Posted August 7, 2013 Share Posted August 7, 2013 Nobody ever gets thanks for....... oh f*ck it, waste a day of your life testing a thermostat and then do whatever the internet tells you. Funny, I have a client who thinks he is pretty clever. Said client is now spending about $150K + loss of income because he didn't listen to professional advice 18 months ago. Link to post Share on other sites
Island Time 1,347 Posted August 7, 2013 Share Posted August 7, 2013 There is nothing wrong with trying to understand your engine, or any other system in your boat. Quite the opposite. However I agree that you should only go against professional advice after careful consideration. There is a lot of crap on the internet, tread carefully. Not all "professionals" are trustworthy, or even competent either. Checking a thermostat is a pretty simple job, and, in this case one not closing properly is easy to see. Any doubt, easy and cheap to replace on most engines. Its not a bad place to start. Don't forget to use inhibitor/antifreeze when you refill the cooling system, as per the owners manual. Link to post Share on other sites
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