Header Tanks

[JackShaftoe]

New to all this so sorry if stupid question.

 

I have two, what appear to be plastic header tanks located to the left and above Beta Marine engine with min/max on them. Both are nearly empty. What do I top them up with? I have some OAT antifreeze coolant already diluted. Will that be ok?

[BEngo]

Depends what is in there already.  If it is OAT then it will be OK.  If it is ethylene glycol or poly ethylene glycol (PEG) then go carefully as mixing OAT with EG or PEG can form a jelly deposit which clags up all sorts of things.  Sometimes.

Try a sample first.

 

N

[JackShaftoe]

Thank you. I went with your advice. It was definitely OAT in before so I topped it up. Quick question on same topic. Should I be worried that both tanks were very low? Does that mean there is a leak somewhere?  

[BEngo]

Possibly.  The best way to check the engine one is to mark the level when cold,  do a normal day's boating and check again the following day before starting.  If it has gone down you are losing coolant somewhere, so need to investigate. The possible causes range from simple to potentially expensive, so find out if you have a problem before worrying.  

 

The second tank I guess to be for the heating system.  Again, mark the level when cold, run the heating normally for a few days and check each time the whole system is cold.

The othr thing you should do is test the antifreeze.  Either get and use an antifreeze hydrometer or simply put samples of your coolants in the freezer overnight. If either sets hard you need more antifreeze in  the coolant soon.  Slushy is safe, but needs doing before a cold snap. Stays runny is OK, no action needed.  When adding antifreeze do not just bung it in neat.  Draw some  coolant off and replace it with a solution of 2/3 antifreeze and 1/3 water, then run the engine/heating to mix it in.  Neat antifreeze can just sink to the bottom of the pipes and sit there.  It is not very effective like that.

 

If there is a problem, there is loads of experience here and folks will help.  Expect lots of questions and requests for detail so in the meantime look carefully at the owners manual, if you have one, for details of your engine cooling and heating systems  and learn how to take and post pictures of your systems.

N

[Chewbacka]

1 hour ago, JackShaftoe said:

Thank you. I went with your advice. It was definitely OAT in before so I topped it up. Quick question on same topic. Should I be worried that both tanks were very low? Does that mean there is a leak somewhere?  

Next time the system is hot the level will be higher as coolant expands when it gets hot, so see how high it Is then.

Don’t fill too high when cold or it will overflow when it gets hot.

[Iain_S]

11 hours ago, Chewbacka said:

Next time the system is hot the level will be higher as coolant expands when it gets hot, so see how high it Is then.

Don’t fill too high when cold or it will overflow when it gets hot.

^^^^^^^^^^ This!

Th header tanks are often re-purposed automotive units and sometimes cannot cope with the expansion of the larger capacity systems in boats when the original max./min. marks are used. So long as the bottom of the tank is covered by an inch or so when the system is cold, the tank will do its job.

 

[Tony Brooks]

16 hours ago, BEngo said:

Possibly.  The best way to check the engine one is to mark the level when cold,  do a normal day's boating and check again the following day before starting.  If it has gone down you are losing coolant somewhere, so need to investigate. The possible causes range from simple to potentially expensive, so find out if you have a problem before worrying.  

 

The second tank I guess to be for the heating system.  Again, mark the level when cold, run the heating normally for a few days and check each time the whole system is cold.

The othr thing you should do is test the antifreeze.  Either get and use an antifreeze hydrometer or simply put samples of your coolants in the freezer overnight. If either sets hard you need more antifreeze in  the coolant soon.  Slushy is safe, but needs doing before a cold snap. Stays runny is OK, no action needed.  When adding antifreeze do not just bung it in neat.  Draw some  coolant off and replace it with a solution of 2/3 antifreeze and 1/3 water, then run the engine/heating to mix it in.  Neat antifreeze can just sink to the bottom of the pipes and sit there.  It is not very effective like that.

 

If there is a problem, there is loads of experience here and folks will help.  Expect lots of questions and requests for detail so in the meantime look carefully at the owners manual, if you have one, for details of your engine cooling and heating systems  and learn how to take and post pictures of your systems.

N

 

Are you sure that is correct. The normal ratio is about 30% antifreeze.

 

I would also say that your test says nothing about the corrosion inhibitors that are the things that get used up. Far better to flush and change as per the antifreeze makers recommendations.

[BEngo]

40 minutes ago, Tony Brooks said:

 

Are you sure that is correct. The normal ratio is about 30% antifreeze.

 

I would also say that your test says nothing about the corrosion inhibitors that are the things that get used up. Far better to flush and change as per the antifreeze makers recommendations.

The  advice was for topping up a sysyem where the antifreeze level is low.  Addinv very strong but part diluted  antifreeze encourages it to disperse moe more readily than neaters.

 

If renewing the coolant completely you would want somewhere between 33 and 50 % antifreeze mixed before filling.

 

I agree about corrosion inhibitors and a full drain and refill, but their lack is not what will damage the engine quickly in a cold snap.  Over dilute antifreeze certainly can, and is easily checked and cured wheras a full drain and refill can be an awkward  job to do properly, particularly since the OP does not seem to have your high levels of experience with boat systems.

 

N