[AT] Off Topic 2001 Ford F250 6.8L engine. Oil pressure gage port size.

[Alan Nadeau]

As Dennis has already stated, any OP sending unit I have seen has been 1/8" 
National Pipe Thread (NPT).  I can be confusing as pipe threads bear 
virtually no relationship to the diameter of the actual threaded 
fitting/sender/widget.  1/8" NPT is very close to 3/8"Ø.

OP senders/switches can fail in some very imaginative ways.  We had one go 
bad on a early-70s Ford Pinto 2.0L engine.  This was a switch, only a light 
for an indicator.  Very cold conditions and it came on while driving down 
the highway.  Light would go out when the engine returned to idle.  Oil 
level was where it was supposed to be.  Installed a new switch, problem went 
away.

Had a OP sending unit, gauge in an '89 GMC, 5.0L.  Gauge in that one dropped 
to almost zero.  Installed a new sending unit along with a mechanical gauge, 
PITA to get at.  Problem went away.

Al Nadeau

----- Original Message ----- 
From: "Dennis Johnson" <moscowengnr at outlook.com>
To: "Antique tractor email discussion group" <at at lists.antique-tractor.com>
Sent: Wednesday, December 14, 2016 10:32 AM
Subject: Re: [AT] Off Topic 2001 Ford F250 6.8L engine. Oil pressure gage 
port size.


>I do not know on this engine, but generally most oil pressure ports are 
>1/8" NPT
>
> Dennis
>
> Sent from my iPad
>
>> On Dec 14, 2016, at 9:25 AM, "tmehrkam at sbcglobal.net" 
>> <tmehrkam at sbcglobal.net> wrote:
>>
>> I am having problems with the oil pressure switch on my F250.  Yesterday 
>> the gauge "Foo Gage" stayed at zero when the engine was started cold.  I 
>> shut it off, checked the oil, started the engine which sounded good and 
>> the gauge finally came up.
>> I changed the oil and Filter Sunday.  Motorcraft oil and Filter So it 
>> could be a number of issues.
>>
>> 1. Bad oil pressure switch.2. Bad check valve in the filter.3. Worn 
>> bearings or oil pump problem.
>> I am getting a new filter and would like to install a mechanical gauge. 
>> Does any one have experience with this engine or the 5.4 Liter engine of 
>> the same vintage. I am going for parts at Noon and would like to know the 
>> port size.  My best guess is 3/8 NPT.
>> PS: Drove it home and then back to work with no indications of low oil 
>> pressure and the gauge worked fine.  But others have reported oil pump 
>> problems on this engine.   I only have 240,000 miles on this thing and do 
>> not want to mess it up.
>>
>>
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