Winter protection for engine

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richardabeattie

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I have a raw water cooled 2GM20. I know I need to flush it out with fresh water at the end of the season (and that the engine must be allowed to suck it up via the impeller rather than being force fed downwards by gravity which risks getting backflow from the exhaust syphon). But then what? Does the panel prefer:

Draining the engine and leaving it empty.
Leaving it full of fresh water and antifreeze.
Using water and an inhibitor. (What is that and where do I get it?)
And how about scale removing additives?
Grateful for any advice!
 
You'll never get all the water out, so you'll probably want a bit of antifreeze in there. That's my plan, anyway. Antifreeze contains inhibitors. If the engine you significant amounts of aluminium (I don't know it, it may well not) make sure your antifreeze says it's suitable. Most, probably all now, are.

And how about scale removing additives?

Probably not a good idea to leave Harpic in all winter /forums/images/graemlins/wink.gif

Brick cleaner, from builders' merchants, is dilute hydrochloric acid. It's the head area that tends to scale up, so that's the bit to concentrate on; IMHO, it doesn't matter too much if you can't get it right round.

On my Volvo 2003, the thermostat's on the top of the head. I plan to take it out, drain off as much water as I can and keep adding brick cleaner until the fizzing stops. I'll then run the engine for several minutes to flush all the crud and excess acid out.

I expect someone'll be along in a minute to tell us this is all wrong - that's life on the Forum. If they have credible reasons, then we'll both have learned something.
 
I always used to flush through with a mixture of anti freeze and cutting oil, then drain and leave on the hard. Didnt bother with any descaling - that takes decades to build up.

Remove impellor and every couple of years its worth taking off the exhaust elbow. You can get corrosion in this area which lets water dribble into the engine and rot the cylinder head. Dont ask me how I know.

Finally I always use to remove the exhaust hose and stuff a rag up the exhaust rather than have damp air in contact all winter.

Did all this make any difference? Probably not, but I'm an inveterate fiddler with things mechanical.
 
If you are going to flush the engine and leave it with antifreeze in you will need to remove the thermostat to get it to circulate throught the engine. I asume you are doing it while the boat is on hard standing and it is unlikely the engine will get up to temperature without load.
 
always a great discussion this. how to and whats the best. the most effective method i have found is as follows:
drain your block before u do anything.it is amazing how many engines have blocked draintaps which can indicate a build up of sludge/silt and restrict cooling.
Change fuel filters if not done previously and bleed. Because you are going to run it to warm the oil/flush you will know if there is any ai left. classic problems on relaunch is the engine stalls just out of the liftingbay because you have just changed the filters but have not ran long enough to check for air!
Run engine on hosepipe. because block is empty the first thing that gets filled is that. the water that sits there while warming up soaks up the salt.
Whilst running check the thermostat casing and block with hand. if it isnt working it will either be shut or open. one way the block stays cool other it gets very hot!
Service as normal. INCLUDING ZINC ANODES IN THE BLOCK!

Now comes the argument point- do i leave the impeller in or out? My advice is fit a new one. the arguments against this are 'it will stay formed or stick over winter'.
Quote from popular impeller manufacturer: 'we have not seen any impellers stay folded for years. different materials used now than in the old days'. if you thinkabout it- most yachts can sit for a couple of months and do nothing. why then do we not get failed impellers every time we start these up? as for sticking- not if lubricated whilst standing....... more later.
Also leaving the impeller out exposes the seal to atmosphere. the seal has a steel spring and is steel coated in rubber (well- most are). moisture + oxygen= rust = early seal failure.

now- DRAIN THE BLOCK AGAIN. this removes the nasty brackish water,hopefully taking out most of the salt. tighten the drain tap.

Run engine on a mixture of antifreeze (50/50 mix with water ) and 10%of good quality inhibiting oil. run until it comes out of the exhaust. my advice is to use oils designed for the task and not plain old cutting oil. reason is the cutting oils can affect seals and rubber......

once this is done the engine is protected from frost where water collects (block, pump, etc) and where water drains away the surfaces are coated with oil. (dip your spanner in the mix- see what i mean?)

then open the decompressors, open throttle wide and turn the engine over on the key for about 10 full revoloutions. this sprays diesel in the bores but does not burn it., protecting the bores.

there is merit to blanking off the intake and exhaust but only if you remember to remove the bungs/ covering in the spring. anyway, most vessels have engineboxes which mean air cant really blow around the engine box, and if you have a exhaust box this is now filled with antifreeze/ oil mix which effectivley shuts the exhaust. of course, there is always the chance of the lesser spotted flugle bird making his nest in your exhaust outlet which really bugger up your launch as it is a protected species and the twitchers would stop you from launching!!

oh- and coat the engine in a maintenence spray which will protect the engine against moisture etc. the one with webbed feet works wonders.

if all goes well launching should be a case of unblock, turn key and sail away. 'cause the impeller is lubricated by the antifreeze/ oil mix!

worked on every boat i have winterised in the past 16 years.
 
This is all great stuff but I wasn't really asking about the whole process of winterising which gets hammered to death every year in PBO - simply the question of what to use to flush the block out and what to leave in the engine through the winter. The message I'm getting is to drain, flush with the thermostat out and leave filled with water and antifreeze. So what was this inhibitor stuff I was shown last year - milky looking oily stuff?

And yes I learned the hard way about providing pressurised water from a hose pipe instead of letting the impeller suck it upwards from a bucket - the water came back from the exhaust and seized the rings - lucky not to have bent a conrod!
 
inhibitor is basically high quality cutting fluid. VP have good stuff which is designed for the purpose. as for thermostat, in all the time i have been doing it i have never had to remove a stat unless there was signs of a problem. if you drain the block the first place the mix will go is in the block. new to this forum and amazed as to the variety of methods people use to winterise. amazingly one of the most effective cleaning solutions i have used if there is a problem is good old Coke. Non diet.
 
Very good procedure. ......But , here in Med where sea temperature during winter is not less than 8 degC common opinion is " IF YOU RUN ENGINE EVERY 20 DAYS FOR 20 MIN DURING WINTER IT IS NOT NECESSARY TO TAKE ANY OTHER PROCEDURE EXCEPT OIL AND FILTERS CHANGING."
Is it correct?
 
What is the purpose of running the engine every 20 days? I can see absolutely no benefit in doing this. It tells you nothing, except that the thing will actually start, which should not be in doubt anyway. I turn mine off the last time it is used, this year 5th October, then change oil and filters and take out impeller. I will not touch it again until May next year.

Running for 20 minutes in gear against warps should be the minimum, everything should then be close to working temperature and harmful deposits of sulphuric acids in the bores may then be flushed through.
 
[ QUOTE ]
harmful deposits of sulphuric acids in the bores

[/ QUOTE ] That is not the only consideration. If the engine does not reach its full working temperautre condensation occurs in the cooler bits like around the valve gear. Surface corrosion of the valve springs can then lead to cracking and ultimately failure. That, I can promise you, is likely to occur at a very inconvenient if not dangerous time and will also leave you with a massive repair bill. (Been there, got the T shirt)
 
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