Low Oil Pressure switch - what seal washer to use with it?

[sweetp01569]

I bought a new low oil preessure switch (the one that controls the dash light). The old one seems to be leaking through the threaded post where the wire attaches. The post spins no matter how much I tighten the nuts, and suspect I broke a seal there, causing my new leak. A week or two before, I replaced the large copper washer for the sensor, which fixed a leak there.

With the new sensor, I bought a separate copper seal washer. However, it looks like a steel washer comes with the sensor. It has a smaller diameter than the copper washer and seems to fit better. The copper washer, is more sloppy on the sensor due to the larger size. Which washer should I use that will seal better, the steel washer that came with the sensor or the copper crush type I bought separately?

Thanks,

Paul

[Delorean Industries]

I bought a new low oil preessure switch (the one that controls the dash light). The old one seems to be leaking through the threaded post where the wire attaches. The post spins no matter how much I tighten the nuts, and suspect I broke a seal there, causing my new leak. A week or two before, I replaced the large copper washer for the sensor, which fixed a leak there.

With the new sensor, I bought a separate copper seal washer. However, it looks like a steel washer comes with the sensor. It has a smaller diameter than the copper washer and seems to fit better. The copper washer, is more sloppy on the sensor due to the larger size. Which washer should I use that will seal better, the steel washer that came with the sensor or the copper crush type I bought separately?

Thanks,

Paul

You should use the washer that was supplied with the warning light depending on where the light was purchased from.

[sweetp01569]

I bought it from DMC Humble TX.


You should use the washer that was supplied with the warning light depending on where the light was purchased from.

[Delorean Industries]

I bought it from DMC Humble TX.

Use the washer provided.

[David T]

Use the washer provided.

That switch is under full pump oil pressure so if it can leak it will. You could also smear some silicone on the washer and make sure the block and the switch is clean. Whichever seal you use you must be sure you get it tight or it will leak no matter what seal you use.
David Teitelbaum

[Delorean Industries]

Silicone is a bad idea on that. Just the washer....

[sweetp01569]

I replaced the old switch with the new on from DMC, and now seals fine with the steel washer it came with. However, the oil light is now on continuously! I rewired with high temp wire, so it's not burning through and shorting with the engine. The new switch came with a male spade type connector, so I installed a female connector on my wire, which works nicely - no wrenches needed to remove the wire. Could a short be present on the switch? The switch came with the spade connector installed tightly between the two terminal nuts with star lock washers. I think there was a lock washer between the inner nut and switch body. Can that possibly cause a short and light to stay on? Does that threaded terminal need to be isolated from the switch body to work properly?

Thanks,

Paul



Silicone is a bad idea on that. Just the washer....

[DMCMW Dave]

Does that threaded terminal need to be isolated from the switch body to work properly?

Thanks,

Paul

Yes.

If you take the wire off the switch and the light goes out, something is wrong with the switch. The center post of the switch is grounded at zero oil pressure, but if it is grounded all the time the light will stay on. If you don't see a plastic insulator between the inner nut and the body of the sender, you need another sender.

[sweetp01569]

It turned out to be the wire burnt again, and shorting on the engine block. I thought I had bought some high temp wire from Home Depot that said 95 deg C on it, but I guess not designed for this use. I put some heat shrink tubing over the wire for now (not sure the heat shrink tubing is high temp rated either). Where can I buy some high temp wire that will withstand the engine temps?

Thanks,

Paul


Yes.

If you take the wire off the switch and the light goes out, something is wrong with the switch. The center post of the switch is grounded at zero oil pressure, but if it is grounded all the time the light will stay on. If you don't see a plastic insulator between the inner nut and the body of the sender, you need another sender.

[Bitsyncmaster]

It turned out to be the wire burnt again, and shorting on the engine block. I thought I had bought some high temp wire from Home Depot that said 95 deg C on it, but I guess not designed for this use. I put some heat shrink tubing over the wire for now (not sure the heat shrink tubing is high temp rated either). Where can I buy some high temp wire that will withstand the engine temps?

Thanks,

Paul

You would need to find a sleeve rated for use near exhaust parts. Don't think any wire insulation will stand up to exhaust parts. Maybe teflon coated wire but that is not very abrasion resistant.

[David T]

You would need to find a sleeve rated for use near exhaust parts. Don't think any wire insulation will stand up to exhaust parts. Maybe teflon coated wire but that is not very abrasion resistant.


Go to a performance shop and buy some fire sleeve. It is pricey though.