Low or no oil pressure showing on gauge

I think I have found the problem with the oil senders and the reason why they fail, need to just check out it once refitted to the car today and lets hope its what I think because if I am right it will cost about less than 10 pence to put em right!!

 

 

 

Enlightenment please!

Looks like you broke the bugger open - Can you get to back together and be oil tight at 80psi on a cold morning? Or let me guess oil doesnt get in that side, it is some sort of button / lever that bends a strain sensor to give the pressure reference. So come on then what is the design flaw and how dya fix it????

Willie

Right update on the oil sender,

Firstly the oil does not get to the parts exposed in the somewhat out of focus pic above.There is a sealed lever point which acts on a spring loaded arm which in turn moves two rubbing strips up and down a variable resister coil.As the movement takes place the resistance of the circuit changes and hence the gauge position.

 

Firstly the earth point is riveted to the base and is not exactly a tight fit, the rubbing strips are also very worn on this particular unit but the most important is a the load resister which is fitted to short out the variable resister slightly ,this is used as a calibration method and this is the main suspect part. Any variance in this resistance would effect the calibration of the unit, the resister fitted is a low wattage / tolerance type and I am speculating heat soak may be causing the resister to change value, this would account for the gauge showning good pressure when a cold engine but a quickly falling gauge as the engine warms up.Combine this with the afformentioned poor earth and worn rubbing strips its a sure thing the unit will fail.

After re-adjusting the strips and securing a better earth point it only leaves the resister to be unsoldered and changed for one of similar value but higher wattage, to hopefully reduce the effect of heat soak.

Time got the better of me today so a refit of the unit was not poss but as soon as it is done will let you all know..here`s hoping.

 

Jeff TT