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Volvo Penta 5.7L alarm not working

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paulikus

New member
all of a sudden, the alarm in my Glastron GX205 Volvo Penta 5.7Lite V8 isn't working. It worked during spring ready but stopped working sometime in the early summer. any ideas what might be the cause? turn the key to accessory and no beep-beep-beep.... thoughts on this?

It also seems that my exhaust manifold and risers are overheating. was pulling a tuber in July and the boat overheated. temp gauge hit 200F or so.
replaced the thermostat but that didn't fix the issue.

thanks!
- paulikus
 
Find the beeper which is usually behind the helm. One side will have 12V when key is turned ON, the other side goes to ECM which applies a ground. Disconnect the ECM wire, turn key ON and ground it to see if it went bad or there is another issue. Can also use scanner to see if ther is an issue

As for your overheating, when was the last time you checked/replaced the impeller?
 
that's a good suggestion on the alarm! I will check that with a meter.

re; overheating, the impeller was replaced last year - summer 2024. with an infrared heat sensor, I recorded the right side exhaust manifold+riser at 114F and the left side exhaust manifold + riser at 124F degrees with the engine idling for 30 minutes. I'm wondering if the waterways/pathways in these components are clogged and not allowing enough cooling to these components? the boat is 23 years old and has only been in fresh water.
 
Temps on mans/risers are fine at those temps. Water flows the path of least resistance and at idle the mans are not full of water

Use a IR temp gun and measure temp at thermostat housing to see if IR reads close to boat temp gauge

Impeller may still be an issue but to test. Get a short piece of clear hose, double barbed fitting and extra hose clamp at local hardware store. Remove the hose coming from the raw water pump at the thermostat housing and install clear hose. Boat needs to be in the water and not on a hose. Run motor and look for bubbles
 
AllDodge said:
Temps on mans/risers are fine at those temps. Water flows the path of least resistance and at idle the mans are not full of water

Use a IR temp gun and measure temp at thermostat housing to see if IR reads close to boat temp gauge

Impeller may still be an issue but to test. Get a short piece of clear hose, double barbed fitting and extra hose clamp at local hardware store. Remove the hose coming from the raw water pump at the thermostat housing and install clear hose. Boat needs to be in the water and not on a hose. Run motor and look for bubbles
Click to expand...
risers and exhaust manifolds were definitely warm/almost hot to the touch during this time. good idea on using the IR temp gun on the thermostat! I'll test that next time I'm near the boat! it's a 140F thermostat - which is what's documented for this engine,
 
If this ia a carburated engine (2002 vintage) then I wiuld guess the overtemp alarm comes directly off the temp switch on t-stat housing or manifold very near by.

I would expect under normal conditions you can always place your hand on the manifold without pain or burns. Any hotter & you would have a fire danger too.
 
Droid said:
If this ia a carburated engine (2002 vintage) then I wiuld guess the overtemp alarm comes directly off the temp switch on t-stat housing or manifold very near by.

I would expect under normal conditions you can always place your hand on the manifold without pain or burns. Any hotter & you would have a fire danger too.
Click to expand...
yes - it has a four barrel Holly carburetor! do you mean the switch that plugs into the thermostat housing?
 
I'm not a Volvo guy but typically there will be 2 switches if an alarm is installed. One sends a signal to the gauge the other to the alarm circuit.
So yes, sort of. Maybe also into t-stat housing or into the manifold very near by.
 
Droid said:
I'm not a Volvo guy but typically there will be 2 switches if an alarm is installed. One sends a signal to the gauge the other to the alarm circuit.
So yes, sort of. Maybe also into t-stat housing or into the manifold very near by.
Click to expand...
I believe the part that screws into the exhaust manifold is a temp or alarm sensor. I've unplugged and re plugged it in a couple times, so I don't think it would be a seating issue.
 
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