2.8 Temp gauge always reads low

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Capri gold
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Car(s): 1987 2.8 Special (weekend driver)
1971 1600 GT (restoration project)

2.8 Temp gauge always reads low

Post by Capri gold »

My temp gauge has only ever reached just above the bottom of the scale at normal running temperature. I've seen this issue mention here before so I've tried to find out what the correct resistance parameters are for the sender but couldn't find any resistance specs for it.

Using a multimeter I tested the one in the car in a cup of near boiling water. With the multi meter set on 20K ohms while the sender was at room temperature the resistance read 1.4 When in the hot water it dropped to 0.35 When I tested an old sender from a mk2 Escort with a white collar I found the room temperature reading was 0.42 and in the hot water went down to 0.08. I tried this one in the car and the gauge now works perfectly, at a little under half way up the scale at normal operating temperature. I've seen it said that the black collar is the correct one. I had a black one in there but it obviously wasn't right as it had a spade terminal on it instead of a pin.

I guess it goes to show not any brand of black collar sender is going to be right. By testing the resistance readings it's easy enough to find out whether the sender is operating in the correct range.
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Andrew 2.8i
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Re: 2.8 Temp gauge always reads low

Post by Andrew 2.8i »

Hi,
The correct sender for the Capri has a white collar.
I'm sure Martin or Tickover can supply a replacement, I found one for sale on Ebay to show you the correct one.
https://www.ebay.co.uk/itm/FORD-CAPRI-M ... ender.TRS0

Andrew.
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steviebabe0
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Car(s): capri 2.8i special

Re: 2.8 Temp gauge always reads low

Post by steviebabe0 »

Hi, just replaced my sender yesterday due to erratic readings. The one I replaced it with was a white one and read 170 ohms at ambient temp unfitted. When held against the radiator when hot it dropped to about 130 ohms. Looks like the what I suspect was the original one was too long and had bottomed out resulting in it being distorted and difficult to remove, and probably why it failed. The replacement one is about 4mm shorter and needle reads half way with engine warm which I think is correct. From memory with old sensor I don't think it ever got off second white line so may have been duff a while.
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