Aftermarket Oil Gauge Sender

[live4theking]

I put an electrical oil pressure gauge in my New Yorker. Last year the gauge started reading lower and lower, but the factory oil light never cam on. I installed a mechanical gauge under the hood just to make sure I still had good pressure - thankfully I do.

So, the aftermarket gauge is a Bosch. Do I have to buy a Bosch replacement sender for it? I don't have a lot of experience with aftermarket gauges.

Thanks for your thoughts.

 

[Big_John]

So, the aftermarket gauge is a Bosch. Do I have to buy a Bosch replacement sender for it? I don't have a lot of experience with aftermarket gauges.

If it's the sender, yes, the best thing to do is match the sender to the gauge.

Here's how it works. Senders measure resistance to ground as the pressure changes. So... let's say your sender and your 100 PSI gauge is setup for 20-100 ohms. At 20 ohms, the gauge will read 100PSI and at 100 ohms, it will measure zero PSI. Think of how your gas gauge works... As the float drops, the resistance increases... Same concept.

The problem is there is no standardization with aftermarket gauges. Another sender might work, but it might also be off if it uses different values. So, the best way to keep it all straight is to use the same sender as the gauge used originally.

That said.... Chances are it's the gauge and not the sender.

If you go to the 4th post in this thread, you'll see how I checked some gauges. Adding Gauges to my 300L I had the values for the Autometer gauges, so I could check them. I took a quick look at the Bosch gauge site and I couldn't find the resistance values for the sender.

 

[live4theking]

Thanks John. You're a scholar and a gentlemen and always for of knowledge.