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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 »

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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Post by oragex »

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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Post by kcodyjr »

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.
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Post by MadeInJapan »

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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Post by abscate »

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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Post by MadeInJapan »

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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Post by beigg »

ugh smh 850 Turbo fridge

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Post by MadeInJapan »

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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