Temp guage

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sdelasal
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Post by sdelasal »

ok - because mine does have the oil level gauge/sender & I was hoping the temperature sensor was in there too. I can imagine as temperature ranges are similar for oil & water - so the sender might be. The oil one would see a lot higher pressure though too.

BX596
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Post by BX596 »

Ey up Mathew.Has Santa come early? Have you got fixed up yet? I've got a set of 4x4 clocks upstairs 8)

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mat_fenwick
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Post by mat_fenwick »

sdelasal wrote:The oil one would see a lot higher pressure though too.
With it being in the sump, the oil temperature sender wouldn't see any real pressure. The oil on mine tends to run about 20°C higher than the water, but lower than this if I drive around without waking the turbo up.
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1993 1.9 TZD Turbo Estate
1996 3.9 V8 Discovery
1993 VW LT35 campervan
1985 Hyundai Stellar V8
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electrokid
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Post by electrokid »

I'm puzzled by the statement that the oil and water temperature senders are the same, as the ones I've seen aren't - the oil temperature sender has a larger thread although the thermistor inside may well be identical...
Ah - I may well have to step up to the plate - admit ignorance - and buy the next round etc :-)

I hadn't got as far as checking threads - only the thermistor resistance required at 100°C which IIRC is 130Ω but I'd have to find my notes to be sure.

So yes - the same electrically - and I did find a couple of manufacturers part numbers so the correct threads for each application may be represented there but again I'd have to dig out the box of bits and measure the thread sizes.

I had 3 instances though where I simply purchased a sender from autofactors and a Citroen dealer - and they were all the wrong resistance - would have shown around 100°C when the real temp was 110°C. Maybe the manufacturers expect the 'dumb' public to think it's going to boil at 100°C rather than 110 !
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mat_fenwick
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Post by mat_fenwick »

Out of interest (as you do!) I checked my oil temperature with a calibrated probe from work in place of the dipstick. When the gauge was as close to 100°C as possible, it was a reading a true 99.6°C, which quite surprised me! Mind you, I would expect the temperature gradients across the oil volume to be at least 5°C...
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1993 1.9 TZD Turbo Estate
1996 3.9 V8 Discovery
1993 VW LT35 campervan
1985 Hyundai Stellar V8
2016 Hyundai iLoad

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electrokid
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Post by electrokid »

That's pretty damn close - impressive !

What I did was to run the instrument pod on the test bench and using 13.8v as a ball-park 'battery being charged' input. I put a potentiometer between the meters and ground which is where the sender / sensor is connected on the car and set the pot so that each gauge in turn read 100° C as near as judgement would allow - then removing the pot and measuring its resistance. In each case it was (from memory :shock: ) 130Ω. This measurement was confirmed by putting a 130Ω resistor in place of the pot and in each case the meter read 100° C.

When buying sensors I tested them by dangling them in boiling water while connected to an ohmeter - those that 'failed' tended to be around the 140Ω - those that 'passed' were within an ohm or 2 of 130Ω.

The sensor supplied by the local Citroen dealer (Bollingmores) failed and they refused to accept its return on the grounds that it's electrical equipment and it's their company policy - so nil points for Bollingmores (and no more business in their direction from me).

Probably a legal point here - distance selling regulations mean that it's probably safer to buy from a dealer on eBay - I had no problems returning a couple of sensors which weren't up to the mark - IIRC one even returned my postage (which theoretically they are supposed to do anyway - but if you're whingeing about something unusual then it's uncertain).
1992 BX19 TGD estate 228K Rusty - SORNed
2002 C5 HDi SX estate