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Adding a Coolant Level Sensor!!

Help, Advice, Owners' Discussion and DIY Tutorials devoted to the second generation C70, S40 and V50 Volvos -- awkwardly model year 2004 ½ onwards -- plus where to go for advice and discussion on Volvo's sporty C30 Coupe powered by Volvo's ubiquitous inline 5-cylinder power plant.
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kcodyjr
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Re: Adding a Coolant Level Sensor!!

Post by kcodyjr » Wed Sep 21, 2016 11:16 am

Depends on how the temperature sensor acts normally. Is overtemp represented by a high resistance or a low resistance?

If overtemp is a high resistance (trending toward an open circuit) then I'd wire the coolant level sensor with it in series, and use a coolant sensor that opens the circuit when the level drops too low.

If overtemp is a low resistance (trending toward a short circuit) then I'd wire the coolant level sensor with it in parallel, and use a coolant sensor that closes the circuit when the level drops too low.

That way, the computer will read a loss-of-coolant event as an immediate overheat.
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Re: Adding a Coolant Level Sensor!!

Post by oragex » Wed Sep 21, 2016 3:35 pm

I'd google see if reservoirs with sensor from other vehicles are small enough to fit the S40, even from other brands, Mazda, Toyota, might be lucky

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Re: Adding a Coolant Level Sensor!!

Post by kcodyjr » Wed Sep 21, 2016 5:47 pm

You know, another option is to wire an open-on-low-coolant sensor in series with the fuel pump relay (control side).

Immobilizing the vehicle if it loses coolant isn't an entirely insane thing to do.
1997 850 GLT sedan, 152K and WHOOHOO!
RIP 1996 850 wagon, 201K, hit by a runaway 4-wheeler
RIP 1996 850 GLT sedan 5spd, 260K, rearended someone
RIP 1986 245 boring, 200K, rusted beyond inspectability
RIP 1981 242 turbo 5spd, 300K, serious teenage crash

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Re: Adding a Coolant Level Sensor!!

Post by MadeInJapan » Thu Sep 22, 2016 9:11 pm

Great ideas!! The sensor I got can either be set to open or close depending on if I turn the float around or not. I looked but there is not much room in our reservoir tanks for much in regards to third party (other maker's float sensors)...the small tank is separated into 6 chambers with walls in the sides. Straight up and down near the filler cap seems the only logical placement. Keep posting everyone!!
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Re: Adding a Coolant Level Sensor!!

Post by abscate » Thu Sep 29, 2016 12:24 am

Well..if you want us to follow at least show pictures of the boat...

How about tying it into a bulb or interior light to give a visual cue?

It is amazing this series uses overheat as the low coolant warning...ouch!

Radio Shavk would have a buzzer that would work here
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Re: Adding a Coolant Level Sensor!!

Post by MadeInJapan » Thu Sep 29, 2016 8:51 pm

Yes, I have considered a buzzer...I'm leaning towards that.
I'd use a light except it was a real bitch to get a thin, smooth boost lines into the cabin for my boost gauge...I can't imagine fishing wires through the thick rubber piece that I had to poke through- it seals up like the rubber port of a medicine bottle as soon as you pull out whatever it is you poke into it.

Boat pictures? Hmmm- let me get the boat in the water (hopefully this weekend) and I'll snap a shot!
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Re: Adding a Coolant Level Sensor!!

Post by beigg » Mon Jan 16, 2017 2:55 pm

ugh smh 850 Turbo fridge

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Re: Adding a Coolant Level Sensor!!

Post by MadeInJapan » Sat Jan 21, 2017 1:01 am

beigg, thanks for your posted links. I really cannot use a different tank as there is no room for much of a tank to begin with. I think I've figured things out but I've gotten lazy and so have not worked on this since last year. When it warms up, I'll cut the actual hole in the bottom of the tank already in the care and give it a go. I just don't want any leaks or else this will be self-defeating!!! But...it looks like the only place I can get a float sensor to sit is from an opening in the bottom of the tank (like my pictures show from page 1 of this thread).
'98 S70 T5 Emrld Grn Met/Beige Tons of Upgrades Mobil-1
'04 V70 2.5T Red/Taupe Some Upgrades Mobil-1
'07 S40 T5 AWD 6 speed manual! Silver/Black Stage1 Heico & Elevate
'07 S60 2.5T Blue/Taupe- my kid's Volvo

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