Coolant 101

[ncbuilder]

Please help me understand how it works.<br /><br />I'm waiting on the full manual but the little manual that came with my Mercruiser 5.0 Alpha drive gives a few steps to drain the seawater section of a closed cooled model. Is this just for winter storage or everytime I use it (saltwater everytime). I've pulled the blue drain plugs on each side and the blue drain plug on the front. Water has drained out. The it talks about cleaning the drain holes on the heat exchanger (can't find anything that looks like the picture). Also it talks about models with seawater pick-up...I'm confused on this all. So, now I have three blue drain plugs out and I'm afraid to do anything else. I really want to make sure I flush anything that I should each time. Can someone give the 101 on this or point me to a link or something? I tried searching but may not have done it long enough or used the right key words so my apologies if this has been rehashed before. -Thank you very much.<br /><br />2000 Bayliner 2050 Capri Mercruiser 5.0 Alpha Drive

 

[Haut Medoc]

Re: Coolant 101

Welcome to iboats <br />No you do not need to drain the sea water section every time......<br />You should however flush the sea water section with fresh water, (on the muffs) after every use.....<br />Don't ever drain salt water into your bilge!<br />I don't have any links for your specific set up, but someone else may....<br />If you post your drive's serial # you will get a more defined response, as there are always changing, (upgrading) different models.....<br />Hope this helps........JK

 

[natwales]

Re: Coolant 101

You really don't have to drain the cooling everytime. Usually that's only when there's a threat of freezing in a raw water cooled model. If you are refering to a closed cooling system, then you really shouldn't have to drain your system very often at all so long as you have the proper level of antifreeze in the colder months.<br /><br />First I'd try to identify if you have a raw water cooled or closed cooled system. Raw water cooled engine will pull water from the pump in your outdrive and circulate that directly through your engine. In a closed cooling system you use the sea water to cool the fresh water that is circulating through your engine via the heat exchanger. If you are having trouble locating the heat exchanger described in your manual Its probably because you have a raw water cooled system. With an alpha drive your seawater pickup is usually the water pump in your outdrive. I doubt you have a seperate seawater pickup pump.<br /><br />If you trailer your boat and use it in salt water it would be a great idea to idle the engine a while on muffs after each use to flush the salt away, but I wouldn't worry about draining it each time.

 

[ncbuilder]

Re: Coolant 101

Wow, you folks are great. Thanks for the quick response. My drive serial #0L785728.<br /><br />I must need to get better muffs because I get more water coming out the edge of the muff than into the sterndrive. I have not tried it idleing yet though.<br /><br />So the water enters the stern drive and then circulates up into the engine hoses? So, the water I drained from the three blue plugs was from the stern drive? Do I just screw the plugs back in and the next time I take it out it'll charge the system again?<br /><br />Also, what is the hose that comes from the engine and lays in the bottom of the bilge? It has a brass plug and a little chain in it.<br /><br />Thank you so much again.

 

[sker crunch]

Re: Coolant 101

The hose with the brass plug is your oil drain. You pull it through the bilge drain. If you put the brass plugs back in then when you ran it on muffs you filled the manifolds with water again, or recharged them as you call it.

 

[ncbuilder]

Re: Coolant 101

Thanks folks.<br /><br />So I'm correct in thinking that the water enters somwhere on the stern drive through the sucton of a pump system?, circulates through the manifold hoses (which have three blue drain plugs at various points to winterize the system) and then exits again through the stern drive. Right?<br /><br />I wonder why the name plate on top talks about coolant fluid then?<br /><br />And I only need to worry about the drains when I winterize because if I run the muffs at idle till I disipate the salt water and replace with fresh water right?<br /><br />Sorry, I'm anal about fully understanding how things work.<br /><br />Thanks.

 

[Don S]

Re: Coolant 101

Your engine serial number is 0L690151 in case you can't find it.<br />Do you have a closed cooling system on your engine? If you do, is it a Mercruiser system, or an after market. Such as SanJuan or Orca.<br />If you are talking about the decal on the engine cover with color codes for oil , coolant, gear lube etc. That is the same decal used on all the engines. IF you don't have that system, you still have the decal.<br />I think all of your questions will be answered once you get your service manuals and can see the different systems and how they work. There is a complete section on the cooling system in the manual. One for raw water, one for closed system.<br />I can try to explain the cooling system and how to flush better when I know if you have a closed or raw water system.<br />Posting a picture of your engine would also help.

 

[ncbuilder]

Re: Coolant 101

Don S - Thank you so much for the help. Here are the pictures. I'm assuming it's raw water right? Sucks it through the stern drive, circulates it around the engine and then discharges through the stern drive. Any water left in the system is fine unless it'll be freezing. And flushing with the muffs just makes sure it's fresh water in the system instead of salt water...am I right?<br /><br />

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