Help! At sea with overheating engine

[Donheist]

Hi - I have a hot engine within 30 mins of leaving anchorage today. Battery charging and temp lights on. The coolant water is a good level but is warm. Strainer is clear. Impeller is good. Belt tension good. But the freshwater coolant reservoir is hot so there is clearly an overheating issue. Alternator is very hot. Water pump wheel hot. Heat exchanger and exhaust don’t feel over hot. I have had problems with the alternator it - needed to jump start the other day because (I later discovered) I had a loose earth on alternator (now repaired and 3 trouble free engine hours since) so it was not charging and not grounding the ignition circuit. Related or red herring?

Any advice on a) cause and b) get me home solution - about 30 miles from a port. There is of course no wind worth having but could probably get to an anchorage - just rather get to a harbour with mechanics and parts.

 

[Robih]

Plentiful raw water being expelled?

 

[AntarcticPilot]

You say the alternator is getting hot. Could it have seized? In that case, can you take the belt off?? How is your freshwater pump driven? Is it from the same belt? If that is so, you need to improvise a belt to run just the water pump (the traditional way is to use nylon stockings, but some rope would probably do as a "get you jome" measure"

 

[Neeves]

Might help if you define the engine.

Jonathan

 

[Donheist]

Plentiful raw water being expelled?

definitely some - hard to tell relative to normal

 

[Donheist]

Might help if you define the engine.

Jonathan

Sorry Volvo penta 2003

Might help if you define the engine.

Jonathan

 

[Donheist]

You say the alternator is getting hot. Could it have seized? In that case, can you take the belt off?? How is your freshwater pump driven? Is it from the same belt? If that is so, you need to improvise a belt to run just the water pump (the traditional way is to use nylon stockings, but some rope would probably do as a "get you jome" measure"

I like it but I think I’ll foul the oil filter. Any way to keep the belt but electrically bypass alternator maybe? I can go back to jump starting

 

[Donheist]

I like it but I think I’ll foul the oil filter. Any way to keep the belt but electrically bypass alternator maybe? I can go back to jump starting

I do have a spare alternator. Maybe I sail to anchorage and swap it

 

[Mistroma]

I like it but I think I’ll foul the oil filter. Any way to keep the belt but electrically bypass alternator maybe? I can go back to jump starting

The point was to check if the alternator was seized. If it is stuck then disconnecting the electrical connection won't help. I doubt a replacement alternator will be of immediate help if the alternator is turning freely.

A hot water pump would tend to indicate lack of flow. Low water flow could account for a hot alternator just because the engine is hot (or did you mean really, really hot). Excess sea water should keep the raw water pump cool, even if the engine is hot.

It's possible that something has plugged the inlet before the strainer. I had that on my previous boat as the inlet was just a normal skin-fitting without an external grill. I used my dinghy pump on the hose to blow it clear. Rodding would have been better but it wasn't a straight run.

 

[fredrussell]

I don’t know about Volvo engines, but on most old tech diesels you can run them for an hour or two without an alternator. The fact that alternator AND temperature lights on is very telling.

 

[Donheist]

The point was to check if the alternator was seized. If it is stuck then disconnecting the electrical connection won't help. I doubt a replacement alternator will be of immediate help if the alternator is turning freely.

A hot water pump would tend to indicate lack of flow. Low water flow could account for a hot alternator just because the engine is hot (or did you mean really, really hot). Excess sea water should keep the raw water pump cool, even if the engine is hot.

It's possible that something has plugged the inlet before the strainer. I had that on my previous boat as the inlet was just a normal skin-fitting without an external grill. I used my dinghy pump on the hose to blow it clear. Rodding would have been better but it wasn't a straight run.

Alternator not seized. Found some wind. Will sail on and run engine just to moor and then see from there. Might get wet and inspect the intake if the marina isn’t too filthy…

 

[Mistroma]

Alternator not seized. Found some wind. Will sail on and run engine just to moor and then see from there. Might get wet and inspect the intake if the marina isn’t too filthy…

Good news that there's some wind as that will allow the engine to cool. It might be easy to jerry rig a short connection to the intake as most boats have a valve connected directly to the skin-fitting. You could disconnect the existing hose and connect a short length of spare hose rising just above the waterline. Water should flood in when valve is opened but not come into the boat. Water level will be visible through the hose or you can lower the hose below the waterline if it's not translucent and collect water in a bucket. You can try to blow back with a pump if no water appears and this should clear a poly bag, weed or jelly fish.

You could just disconnect the hose at the sea-water pump if you don't have any spare hose. At least it will show if water is reaching the pump or not.

Do you know if your inlet has a filter on the hull or if it is just a normal skin-fitting? The latter can be blocked pretty easily.

 

[Amlov]

Assume the alternator is a red herring and work back.

Most likely is impeller, check it is ok and also not spinning on the middle. Check for inlet blockage and good water flow coming out in the exhaust.

Consider jammed thermostat and only once you have gone through the obvious think about the alternator.

If the alternator is spinning and the internal coolant pump is turning then I doubt that the alternator is your primary problem. They do run hot when putting out a big charge.

 

[scottie]

Other thread running on 2000 series overheating found to be fresh water pump impeller spinning on shaft solved temporarily by pinning?

 

[Donheist]

Alternator not seized. Found some wind. Will sail on and run engine just to moor and then see from there. Might get wet and inspect the intake if the marina isn’t too filthy…

Update: wind dropped so I thought I’d try one more thing. Flow defo not right - some but not enough. Sound not right either - as if cock is closed. Must be intake. So I gave it a ton of astern and then paused and gave it a ton of ahead. Then flow! Now been running at half revs and so far so good. That’s twice in two seasons I’ve had that. Last year a crisp packet - this year - maybe a mollusc or something. Maddening! Might need to see if I can for a grill when I haul her next

 

[Donheist]

Update: wind dropped so I thought I’d try one more thing. Flow defo not right - some but not enough. Sound not right either - as if cock is closed. Must be intake. So I gave it a ton of astern and then paused and gave it a ton of ahead. Then flow! Now been running at half revs and so far so good. That’s twice in two seasons I’ve had that. Last year a crisp packet - this year - maybe a mollusc or something. Maddening! Might need to see if I can for a grill when I haul her next

Ps - thank you all so much for help. Ruling things out helps give one the confidence to focus on what is most likely. Thank you!

 

[jlavery]

Not sure if this has been mentioned in the suggestions above, regarding blocked intake - checking and clearing.

This is what I did with my engine (D1-30, but similar applies to any engine).

If you've got easy access to the raw water pump, disconnect the intake pipe with the seacock open. You should get water gushing out (have a bucket ready to catch the water). If it's not gushing, then there's likely to be a blockage. Try blowing down the pipe to clear it. When I had a problem, I could tell there was resistance, and felt it clear. Can also try poking dinghy inflation pump into hose and pumping hard down the pipe.

 

[Buck Turgidson]

Last month in the med my sea temperature was indicating 31°C. I wasn't convinced it was accurate but for the first time when I did my Italian tune up the engine overheated after 20minutes at full power. Water flow looked normal and no problems once cooled and run at normal speed. I didn't have time to check the inlet or impeller but they are on my to-do list before the next sail.

 

[Mark-1]

Update: wind dropped so I thought I’d try one more thing. Flow defo not right - some but not enough. Sound not right either - as if cock is closed. Must be intake. So I gave it a ton of astern and then paused and gave it a ton of ahead. Then flow! Now been running at half revs and so far so good. That’s twice in two seasons I’ve had that. Last year a crisp packet - this year - maybe a mollusc or something. Maddening! Might need to see if I can for a grill when I haul her next

Out of interest, why astern and ahead?

 

[Buck Turgidson]

Out of interest, why astern and ahead?

my guess was one of these:

But still not sure why it would help as the engine is pulling water in both directions.