Follow-up question on VP 5.0 GL-B Thermostat Alarm

Misterbulbous

Seaman Apprentice
Joined
Jul 12, 2018
Messages
47
re: 2002 VP 5.0 GL-B...

As mentioned several weeks ago, I've been having an issue with an alarm coming from my thermostat sensor. The alarm conditioned has persisted before and after changing my thermostat and is somewhat sporadic, but once it starts, it's here to stay until the next day.... I'm running a 160° thermostat and verified that it opens up ok (see below for another question...). The engine temperature runs about 165~170 at all rpms in the garage. Maybe slightly hotter out on the lake.

I can't recreate the alarm with muffs, and don't live near a lake where I can evaluate more accurately (water temperature in Tennessee/Kentucky lakes about 85° now). It's really a nuisance and can be unsettling when you are on the water.

Question 1. I'm trying to understand if my sensor is bad...Does anyone know if it's possible to swap the signals between the engine temperature sensor and the thermostat sensor? Would I be able to send the thermostat sender to my instrument panel gage and see what temperature it's reading? Any other idea or troubleshooting method? Obviously I could buy a new sensor. Just looking for thoughts here.

Question 2. My 160° thermostat actually appears to start opening around 170~172°, so I thought maybe that was a problem. Bought a brand new thermostat and it also opens up about 10~12 degrees higher than the rating. Does anyone else know if that's typical? Both definitely don't open in the 160's.

Appreciate comments...
 

Bondo

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Apr 17, 2002
Messages
71,095
Question 1. I'm trying to understand if my sensor is bad...Does anyone know if it's possible to swap the signals between the engine temperature sensor and the thermostat sensor? Would I be able to send the thermostat sender to my instrument panel gage and see what temperature it's reading? Any other idea or troubleshooting method? Obviously I could buy a new sensor. Just looking for thoughts here.

Welcome Aboard,...... Nope,.... the temp Sender measures varyin' resistance to ground to the gauge,.....

The alarm Switch, is all or nothin' to ground,.....
 

Misterbulbous

Seaman Apprentice
Joined
Jul 12, 2018
Messages
47
Welcome Aboard,...... Nope,.... the temp Sender measures varyin' resistance to ground to the gauge,.....

The alarm Switch, is all or nothin' to ground,.....

Thanks. I did not know that about the thermostat sender/"switch". Would you think it's reasonable for both to "see" the same water temperature? I suppose I could take the thermostat sender out and do a hot water check and see what temperature it opens up at.
 
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