WHY IN THE HELL Is our car going through OIL PRESSOR UNITS ?

doesn't sound right, how many miles on her?

what is an oil pressor unit?

 

It's well known that any oil sender must be installed with a special oil sender socket or the hex might be distorted and caused to leak at the seals inside.

 

I never knew that.

 

Lisle 13250 Oil Pressure Switch Socket

 

i thought everyone knew that

 

If I knew it I forgot it when I was stressed out messing with the Harrier Jump Jets

 

The one I installed in my Mazda with a regular deep socket never leaked in the remaining ~440k miles I had the car. Maybe I didn't overtighten it enough to distort it.

 

The Repair Manual (more info) says, when installing the engine oil pressure switch assembly, to use a “24 mm deep socket wrench,” with no mention of any special service tool. The stated torque specification (15 N·m) is much lower than for typical M16 or M18 bolts, however. The technician is also instructed to apply Three Bond 1344 adhesive (for which other Toyota publications identify LOCTITE 242 as equivalent) to two or three threads before installing the switch, and to wait at least an hour after installation before starting the engine.

 

obviously, whoever wrote the manual didn't know

 

I've only used an oil sender socket on those oddly shaped ones - though you do need to be gentle with them. Never over-torque them or they will leak, down the road. I also use teflon tape on the threads, so if it feels like it's binding - I stop there, even though I haven't reached the specified torque specs. I only had to replace one unit a second time, factory defect - kept dropping out.

 

Yeah 15 N/M's equates to 11 foot/pounds, very low. 3/8" or 1/4" drive torque wrench would be good.

 

As I recall, the industrywide standard for oil senders hearken back to the early days of automobiles. It is not metric buy 1/8x27 National pipe thread. Tapered pipe threads generally require a high torque value,

Thus, there is a need for some sort of sealant at low torque.

 

i have never heard that too much oil can do it, and we've had plenty of too much oil reports.

this is a pretty unusual problem

 

Only you can answer those. Are you torquing it to 11 foot pounds?

 

The world is weirder than that. NPT (national pipe taper) is "national" to the US. The standard Toyota is using is BSPT—a British standard, but one that more of the world uses.

It is still designated in inch fractions. But several things are different. A 1/8 BSPT has 28 threads per inch, compared to 27 for 1/8 NPT. It can be close enough to seem to be threading in ok, but not really.

Adapters from BSPT to NPT are available, and often included in oil pressure test kits.

 

So maybe a previous owner installed a NPT thread variant PCV valve?

If that’s the case, at least the PCV valve screws into a small bolt-on plate, not directly into the block.