How many temp sensors on 5.0 mercruiser?

[saltwater_cowboy]

I have a circa 1988 5.0 mercruiser and it seems to have 3 engine temp sensors. Is this normal. There is on on the engine water pump, one on the top of the inlet manifold and one at the rear of the engine.<br /><br />The reason I'm asking is beacuse I need to remove the one on the water pump to source a hot water supply.<br /><br />There is two outlets on the water pump, one at the top and one on the side where the temp sensor is located. The top one is rusted solid and will not budge. The temp sensor one unscrewed fine.<br /><br />I'm thinking with the other two sensors it should still be ok?<br /><br />Thanks<br /><br />J

 

[Don S]

Re: How many temp sensors on 5.0 mercruiser?

How many senders depends on if there is an alarm system or not. Usually there is one sender for the gauge on the intake manifold (Starboard side next to thermostat housing). I don't ever remember seeing one installed in the engines circulation pump. Is it in the top of the pump? If so, it may be an aftermarket alarm system and is a temp switch that turns on the alarm at a certain temp.<br />Just at the back of the intake manifold (actually on the block on the port side of the distributor is an oil pressure sender, not water temp.<br />Here are the hose hookup locations.<br /><br />

 

[saltwater_cowboy]

Re: How many temp sensors on 5.0 mercruiser?

Yes there is a temp sender on the pic on the right where the plug is fitted.<br /><br />The plug at the top of the pump is too rusted to remove.<br /><br />No aftermarket warning system fitted I can see, just one temp guage.<br /><br />Will have a look where the wiring goes.