Engine loosing coolant

[Stu Jackson]

Do you think it makes sense to change the hoses...?

My 2cents...Yes and No.  If it were me I'd find the leak/leaks first.  Then decide on hose replacement, if original they are 20 years old.  ..............
.............................................................................

When my boat reached your boat's age, I simply changed all the hoses and clamps.

I only did a few at a time, following Ron Hill's advice that if you fix too many things at once, you'll never find out just where the problem was to begin with.

It's a wise investment to change them all.   When you see the condition of the hose from the engine to the water heater, you'll know why.  (Photos linked in the Critical Upgrades topic.)

Those Critical Upgrades were originally conceived, (as so noted in the introduction in the first post) to capture recurring issues.  Many of them were "corrected" in later models of the boats, but not all of them.  One recurring one was to check your engine while running, which almost always led to "hose replacement" or new raw water pump seals.

I had a tiny coolant leak at the fresh water coolant pump.  I feared the worst.  Turned out to be a loose hose clamp.

Your boat, your choice.   

But why would you not want to?

[waughoo]

Currently going through a full hose replacement on my new to me 91.  The idea is that i like to know the replacement date.  This gives me at least a known quantity even if some of the hoses have a service life left in them.

[sailaway]

Had 1986 M25 in Lake Erie lost engine coolant every winter. Filled it up and ran all summer without topping it off. Never really figured it out, I did suspect the engine to coolant pump gasket.

[Robert Mann]

PB, If the coolant is in the lazerette it really only come from the top of the expansion tank, from the hose connection to the expansion tank, a crack in the expansion tank or the hose is cracked and leaking.  Could be it's finding it's way from the lazerette to  the bilge.

More concerning to me would be why is it low on coolant in the pressurized engine tank.  Is it leaking from a hose, a fitting, a head gasket or where.  It would be worth topping up and then manually pressurizing the system (Auto Zone for a tool loan) and seeing if you can spot a leak while the engine is cold and you don't get singed reaching around the engine. 

If you aren't finding the oil level increasing then the coolant most likely isn't finding it's way to the oil pan, and/or if you aren't seeing steam and smelling glycol when the engine runs the head gasket is good.   

It might be you have 2 issues going on here.  Lazerette leak is a PITA, the other more tricky and needs fixing.

[pbyrne]

I'll have to review the critical upgrade photos.

I stuck my head and hands into every area I could today and noticed that, possibly, the hose on the left side of the engine that is connected to the heat exchanger was ever so slightly damp.  I've refilled the engine coolant to full and put shop towels under the engine in various locations and everywhere I think there is a coolant connection.  I'll check back on it in a couple of days.

Do you think it makes sense to change the hoses...?

My 2cents...Yes and No.  If it were me I'd find the leak/leaks first.  Then decide on hose replacement, if original they are 20 years old.  ..............
.............................................................................

When my boat reached your boat's age, I simply changed all the hoses and clamps.

I only did a few at a time, following Ron Hill's advice that if you fix too many things at once, you'll never find out just where the problem was to begin with.

It's a wise investment to change them all.   When you see the condition of the hose from the engine to the water heater, you'll know why.  (Photos linked in the Critical Upgrades topic.)

Those Critical Upgrades were originally conceived, (as so noted in the introduction in the first post) to capture recurring issues.  Many of them were "corrected" in later models of the boats, but not all of them.  One recurring one was to check your engine while running, which almost always led to "hose replacement" or new raw water pump seals.

I had a tiny coolant leak at the fresh water coolant pump.  I feared the worst.  Turned out to be a loose hose clamp.

Your boat, your choice.   

But why would you not want to?

[pbyrne]

Took a photo of the port lazarette hoses.  It doesn't look like anything is coming from the recovery tank into the bilge.  Hoses show no signs of being wetted and are dusty.  Nothing I could see along hull either.

That may point to a cracked tank or hose clamp.  It's completely empty so the crack my be on the bottom out of sight.

PB, If the coolant is in the lazerette it really only come from the top of the expansion tank, from the hose connection to the expansion tank, a crack in the expansion tank or the hose is cracked and leaking.  Could be it's finding it's way from the lazerette to  the bilge.

More concerning to me would be why is it low on coolant in the pressurized engine tank.  Is it leaking from a hose, a fitting, a head gasket or where.  It would be worth topping up and then manually pressurizing the system (Auto Zone for a tool loan) and seeing if you can spot a leak while the engine is cold and you don't get singed reaching around the engine. 

If you aren't finding the oil level increasing then the coolant most likely isn't finding it's way to the oil pan, and/or if you aren't seeing steam and smelling glycol when the engine runs the head gasket is good.   

It might be you have 2 issues going on here.  Lazerette leak is a PITA, the other more tricky and needs fixing.

[KWKloeber]

Did you check tightness of and/or bulged/leaky gaskets under Hx end caps, and/or leaky around the anode thread?

[pbyrne]

Not yet but I will now!  This is all new to me so it's safe to assume that I haven't checked anything like that unless it is mentioned.

Are you talking about the anode that is on starboard side, bottom of the heat exchanger?

Also, what does a bulged gasket look like?  I've attached a photo of the gasket I think you're referring to.

Did you check tightness of and/or bulged/leaky gaskets under Hx end caps, and/or leaky around the anode thread?

[KWKloeber]

Well actually removing/checking under the caps should be annual maintenance to assure there's nothing blocking the small diameter tubes in the Hx.  When you remove the cap sometimes you see the gasket had swollen or bulged and maybe not making complete contact (replace them) since there's only the center bolt (unlike a pump that has multiple pressure point bolts) sometimes the covers gets bent as well.

BUT if you're POSITIVE it's engine coolant it wouldn't be caps or the anode (they're on the seawater side of the Hx, the coolant side is closed so to speak.  A VERY long shot, there's ONE time you could get mixed coolant and seawater out the caps or anode.  If a pinhole develops in the Hx in one of the small tubes that carry the seawater (happened to mine) the "radiator cap" pressure pushes coolant thru the pinhole into the seawater side (typically gets carried out the exhaust but (unlikely) a trace of coolant could leak from any hose carrying the mixture.)  The coolant level keeps disappearing and the engine overheats with no obvious cause (you don't realize the dropping coolant level is disappearing out behind the boat.)

PS - if that happens to limp back loosen the pressure cap so the coolant isn't forced out thru the pinhole (and slow down!) You may boil off coolant and need to keep a sharp eye, but won't lose as much coolant as it being forced out the exhaust under pressure.

[Ron Hill]

pby : To check if it is coolant, just take a drop and taste it. If it's sweet it coolant!!

A thought

[pbyrne]

What if it's not coolant!?? I have years ahead of me!

pby : To check if it is coolant, just take a drop and taste it. If it's sweet it coolant!!

A thought

[pbyrne]

Fortunately she's never seen seawater.  Not that you can't have problems, but corrosion issues are likely to be less of an issue.

That is a very good tip for a coolant leak, and something to keep in mind!  God forbid I need that knowledge but I won't forget it! Thanks!

Well actually removing/checking under the caps should be annual maintenance to assure there's nothing blocking the small diameter tubes in the Hx.  When you remove the cap sometimes you see the gasket had swollen or bulged and maybe not making complete contact (replace them) since there's only the center bolt (unlike a pump that has multiple pressure point bolts) sometimes the covers gets bent as well.

BUT if you're POSITIVE it's engine coolant it wouldn't be caps or the anode (they're on the seawater side of the Hx, the coolant side is closed so to speak.  A VERY long shot, there's ONE time you could get mixed coolant and seawater out the caps or anode.  If a pinhole develops in the Hx in one of the small tubes that carry the seawater (happened to mine) the "radiator cap" pressure pushes coolant thru the pinhole into the seawater side (typically gets carried out the exhaust but (unlikely) a trace of coolant could leak from any hose carrying the mixture.)  The coolant level keeps disappearing and the engine overheats with no obvious cause (you don't realize the dropping coolant level is disappearing out behind the boat.)

PS - if that happens to limp back loosen the pressure cap so the coolant isn't forced out thru the pinhole (and slow down!) You may boil off coolant and need to keep a sharp eye, but won't lose as much coolant as it being forced out the exhaust under pressure.

[KWKloeber]

>>> Fortunately she's never seen seawater.  Not that you can't have problems, but corrosion issues are likely to be less of an issue.<<>

My M-25 was always freshwater (Ontario/Erie) and developed the pinhole Hx leak (2" Hx) about 11-12 years young, maybe 3-4 years after I got her.

[pbyrne]

I will keep it in mind.  At the moment the amount in the bilge points to something else, but you never know!

>>> Fortunately she's never seen seawater.  Not that you can't have problems, but corrosion issues are likely to be less of an issue.<<>

My M-25 was always freshwater (Ontario/Erie) and developed the pinhole Hx leak (2" Hx) about 11-12 years young, maybe 3-4 years after I got her.

[Stu Jackson]

Fortunately she's never seen seawater.  Not that you can't have problems, but corrosion issues are likely to be less of an issue.

Less of an issue???...hardly.

Water corrodes, all water corrodes, saltwater corrodes absolutely.  Not much difference if what's in saltwater is rinsed liberally.

That's why we keep suggesting to check your engine when it's running.  A saltwater leak from your raw water pump can ruin a lot of metal parts below it.