How to Install oil pressure and temp gauge on 165 merc

Bullhauler

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1978 mercruiser 165 v6, want to put in a temp gauge and oil pressure gauge, can anyone tell me where and if there are locations on motor to plug into? Its in a glastron ssv 177, thanks
 

mboudre1

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Re: How to Install oil pressure and temp gauge on 165 merc

Usually there should be a spot on the thermostat housing for the temp gauge...and a plug you can remove on you engine block for the oil pressure gauge.
 

achris

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Re: How to Install oil pressure and temp gauge on 165 merc

1978 mercruiser 165 v6, want to put in a temp gauge and oil pressure gauge, can anyone tell me where and if there are locations on motor to plug into? Its in a glastron ssv 177, thanks

That does not compute. Merc didn't start using V6s until 1983, and then they were (3.8 litre) 185, not 165. Are you sure it's not an in-line 6, 165?

Please include the serial number of the engine in your post.

ALL Mercruiser engines, starting way back in the 60s have oil pressure and water temperature gauges as standard issue, complete with senders already in the engine..
 

04fxdwgi

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Re: How to Install oil pressure and temp gauge on 165 merc

That does not compute. Merc didn't start using V6s until 1983, and then they were (3.8 litre) 185, not 165. Are you sure it's not an in-line 6, 165?

Please include the serial number of the engine in your post.

ALL Mercruiser engines, starting way back in the 60s have oil pressure and water temperature gauges as standard issue, complete with senders already in the engine..

Somehow sounds like Frankenstein'd setup. Don't recall ever seeing a Mercruiser w/o gauges. Even an old '73 Bayliner I had (and it was a barebones junker), had the gauges. Maybe an automotive engine McGuiver conversion by some prior owner.
 

Bullhauler

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Re: How to Install oil pressure and temp gauge on 165 merc

its not v6 but an inline 6 165hp, my bad on the info, has all the gauges but the oil pressure and temp....but does have a temp light in dash that comes on if it reaches too high temp just wanted to have a gauge to monitor.

and no its not a frankestein mcquiver engine conversion setup
 

04fxdwgi

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Re: How to Install oil pressure and temp gauge on 165 merc

its not v6 but an inline 6 165hp, my bad on the info, has all the gauges but the oil pressure and temp....but does have a temp light in dash that comes on if it reaches too high temp just wanted to have a gauge to monitor.

and no its not a frankestein mcquiver engine conversion setup


Didn't mean to diss. The V-6 thing thru me off. Find your oil pressure sender for your light (Should at least have a low pressure light) , remove it and put a "t" in there and reinstall into one of the "t" openings. Install the oil pressure sender (Electronic gauge) or plastic line (mechanical gauge) in the other opening and you are good to go. On the temp, there should be a plug in the water jacket or most likely, thermostat housing somewhere that you could remove and install a tem gauge sender.
 

Bullhauler

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Re: How to Install oil pressure and temp gauge on 165 merc

Didn't mean to diss. The V-6 thing thru me off. Find your oil pressure sender for your light (Should at least have a low pressure light) , remove it and put a "t" in there and reinstall into one of the "t" openings. Install the oil pressure sender (Electronic gauge) or plastic line (mechanical gauge) in the other opening and you are good to go. On the temp, there should be a plug in the water jacket or most likely, thermostat housing somewhere that you could remove and install a tem gauge sender.

no offense taken...thanks for the info that'll help me out
 

Will Fish

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Re: How to Install oil pressure and temp gauge on 165 merc

The oil pressure sender should be right near the oil dipstick above the starter. As for the water/temp, there should be a port if not 2 on the thermostat housing on the very front of the motor.
 

Bullhauler

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Re: How to Install oil pressure and temp gauge on 165 merc

The oil pressure sender should be right near the oil dipstick above the starter. As for the water/temp, there should be a port if not 2 on the thermostat housing on the very front of the motor.

Thanks for locations
 

Bullhauler

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Re: How to Install oil pressure and temp gauge on 165 merc

op.jpgwater temp.jpg

snapped two pics, looks like i have a oil pressure sender already in, their is a green wire coming out of the sender but i have no gauge in dash, so not sure where the green wire is going to but could i hook up a gauge to this sender?

2nd pic is of the thermostat housing, looks like this is the sender that is wired to the high temp light in dash, can i just disconnect this wire and hook it up to a gauge instead or could i wire up both a gauge and leave the warning light hooked up as is so just y off one wire?
 

achris

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Re: How to Install oil pressure and temp gauge on 165 merc

Warning lights and gauges use different senders. Warning lights use switches, on or off. Gauges use senders that vary the resistance (usually) between 33Ω and 240Ω... So no, you can't use a warning light switch for a gauge....

You can put a gauge sender in the engine and have both the gauge and the warning light, but they need to run on separate wires. You could even hook the warning light switches up to a warning buzzer as well (as the warning light).... That way if you miss seeing the light, you might hear the buzzer...

Chris......
 

Bullhauler

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Re: How to Install oil pressure and temp gauge on 165 merc

from the pic of the oil pressure sender above dipstick, least i think its an oil pressure sender, any idea what one green wire would be going to? was their any kind of of low oil pressure shut down features on these 78 mercruisers? suppose i could just get a gauge and wire it uip to see if it would work.

think I just get a 2nd sender for thermostat for 2nd plug in and leave the warning light hooked up as is
 

Bullhauler

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Re: How to Install oil pressure and temp gauge on 165 merc

anyone know what size thread is on the thermostat housing for the 2nd sender?
 

achris

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Re: How to Install oil pressure and temp gauge on 165 merc

To check that device in the oil passage, unhook the wire and put a multimeter on it. If it shows around 240Ω, then it's a sender and will run a gauge. If it shows a dead short, it's a switch and will not run a gauge....

As for the run of the wire, no idea, my crystal ball's off for a 10,000 guess service... try disconnecting the engine harness plug and metering point to point until you find it... If the wiring is still standard as from the factory, then the oil pressure sender wire should be light blue and go to pin 8 on the engine harness plug.... But you're saying it's green, so all bets are off....

Chris.........
 

achris

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Re: How to Install oil pressure and temp gauge on 165 merc

anyone know what size thread is on the thermostat housing for the 2nd sender?

Take the plug out and measure it yourself... or take it with you to the shop and ask the kid behind the counter to supply a gauge sender for that thread.... And a gauge to match.... (I would recommend you use a 33Ω to 240Ω gauge and sender)...

Chris........
 

Bullhauler

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Re: How to Install oil pressure and temp gauge on 165 merc

k thanks, was really hoping your crystal was operational today! i'll get er figured out
 

Bondo

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Re: How to Install oil pressure and temp gauge on 165 merc

2nd pic is of the thermostat housing, looks like this is the sender that is wired to the high temp light in dash, can i just disconnect this wire and hook it up to a gauge instead or could i wire up both a gauge and leave the warning light hooked up as is so just y off one wire?

anyone know what size thread is on the thermostat housing for the 2nd sender?

Ayuh,.... Take pictures of the t-stat housin' from another side,...

That plug appears to be 1/4" pipe, or possibly 1/8" pipe,...

I'd think there oughta be a 1/2" pipe port,...away from the pulley...
 
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