Oil Sending Unit Help

[John-Ryan]

See the attached pics... Noticed a small leak out of the sending unit yesterday. Swing in there parts store, grab new one rated at 60 psi. On my bench is laying the one outta the engine (Lesson learned - take the old part along) that has a much bigger thread like the LS versions. The one called out for my 350 TBI in the book is taller and a thinner shaft on the bottom. I found where I can buy an LS adapter that will work with the new but would like to have as least amount of connections as possible. The old unit came out easy and fit just fine with the existing tee. What options do I have that y'all have come up with when owning a Frankentruck lol
Thanks!

 

[Redfish]

I think you have the wrong unit. The 1/8 inch thread version is usually for a light, the 1/4 inch threads (like your old one) are for a gauge. I just replaced this unit on my 350 TBI and I had to order it through RockAuto. Sourcing one locally was nearly impossible and what I got was junk that didn't last and never read correctly.

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[John-Ryan]

I think you have the wrong unit. The 1/4 inch thread version is usually for a light, the 3/8" threads (like your old one) are for a gauge. I just replaced this unit on my 350 TBI and I had to order it through RockAuto. Sourcing one locally was nearly impossible and what I got was junk that didn't last and never read correctly.

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Roger that! I went to return the wrong one and they looked for 30 mins as I did at home on google, ebay, forums, etc.. They did find the right one and have two brands of it coming to the store tomorrow. Didn't pay yet so we will have to wait and see the qulaity. Saw your post the other day on the same thing and thought it was funny how mine just started leaking lol Thanks for the help!

 

[Redfish]

Roger that! I went to return the wrong one and they looked for 30 mins as I did at home on google, ebay, forums, etc.. They did find the right one and have two brands of it coming to the store tomorrow. Didn't pay yet so we will have to wait and see the qulaity. Saw your post the other day on the same thing and thought it was funny how mine just started leaking lol Thanks for the help!

FYI, I didn't learn about the pipe size being related to the function until I was shopping for mine on RockAuto. That is actually a pretty easy way to do it. They list a bunch of different brands and prices and I noticed that the 1/8 inch was for the Idiot Light. I had no clue up to that point.

If you saw my post, you saw the ohm readings. The pic I posted is the bad unit, the good one should be around 3 ohms I think.

 

[Turbo4whl]

I think you have the wrong unit. The 1/4 inch thread version is usually for a light, the 3/8" threads (like your old one) are for a gauge. I just replaced this unit on my 350 TBI and I had to order it through RockAuto. Sourcing one locally was nearly impossible and what I got was junk that didn't last and never read correctly.

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Pipe threads are measured by the ID of the pipe.

The small size @John-Ryan pictured (Standard PS154) is 1/8" pipe. The old one he removed is 1/4" pipe. Yes the outside is larger than the stated pipe size.

John I hope the parts house can get you the correct sender. The Standard box clearly states switch. Both pressure switches and pressure sensors (senders) can be either 1/8" or 1/4" pipe.

 

[Redfish]

Pipe threads are measured by the ID of the pipe.

The small size @John-Ryan pictured (Standard PS154) is 1/8" pipe. The old one he removed is 1/4" pipe. Yes the outside is larger than the stated pipe size.

John I hope the parts house can get you the correct sender. The Standard box clearly states switch. Both pressure switches and pressure sensors (senders) can be either 1/8" or 1/4" pipe.

You are correct, I got my pipe sizes mixed up. They are 1/4 and 1/8 inch.

On my 350 TBI there are two separate units. The 1/8 inch switch sits under the distributor and against the firewall. The 1/4 inch sender is under the truck, close to the clutch slave cylinder. But they are shaped entirely differently.

For my year (1987) the listings I found all had the smaller, 1/8 inch thread version listed as a switch with the 1/4 inch size listed as a sender. I am certain that things change and that they probably do have versions in both sizes. I am also certain that just because I read it on the internet doesn't mean it's true...

I went back and edited my earlier posts to prevent confusing anyone with my size mistakes.

 

[John-Ryan]

Good report!
They ordered the correct part and was identical to the unit I took in. They had 2 different brands available and chose the one without the Teflon tape but rather the red loctite look on the threads. It is installed and no leaks and gauge is all good.

 

[Camar068]

This is a sender and a switch all in one picture. The can is what says it's a sender (gauge). The other is a switch for idiot lights.

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[roundeyed sqbdy]

This is a sender and a switch all in one picture. The can is what says it's a sender (gauge). The other is a switch for idiot lights.

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Where are you buying the non idiot light unit? Model number? Brand?

 

[80BrownK10]

Where are you buying the non idiot light unit? Model number? Brand?

You can buy them anywhere, eBay, Amazon rock auto, O'Riley, AutoZone or advance.

 

[roundeyed sqbdy]

1/4 npt works for me.. got this one from amazon.