Q: Oil pump replacement?

[JUSTTOHAVE]

Hi. My PJ #458 is showing low oil pressure at idle once the oil comes up to temp. When started, it's around 75 then settles to 50 at 70mph/2000rpm while driving. Once the oil is around 175 degrees and I come to a stop light, the pressure drops to darn near zero. When I get back on the gas, it goes right back up to 40-50. I was thinking about changing out the oil pump but I'm not certain if it's a normal Ford unit or something more high performance? Any help would be appreciated.

[Aussie-Parnelli]

I believe the oil pump is the original ford unit, is it reading low on both gauges.
I would be checking the oil pressure switch first or putting a mechanical gauge on it to check exact pressure.

Tony

[jcar302]

Put a mechanical gauge on it.
Let the car warm up and see what hot idle is.

Oil pumps usually work or don't. So even if you changed it, I don't think the results will be any different.

[JUSTTOHAVE]

Thanks to both of you who replied. I will try the mechanical gauge first and go from there. Much appreciated.

[Jason @ 281m]

What oil thickness are you running and what brand? I dont think this is your only problem but its worth knowing.

[JUSTTOHAVE]

Hello and thank you for asking- 6 quarts of Mobil 1 5w/30

[Aussie-Parnelli]

Mobil 1 is the only oil I have used in the Parnellis and Extreme
I use Penrite ten tenths 5W 30 racing oil in 2006

Tony

[Jason @ 281m]

Originally Posted by JUSTTOHAVE

Hello and thank you for asking- 6 quarts of Mobil 1 5w/30

Have you done a compression test? BTW, I would run 10w30.

[JUSTTOHAVE]

Ok, first I will check the oil pressure with a mechanical gauge then follow up with a compression test. Why 10w30 instead of 5w30?

[JUSTTOHAVE]

Actually, the car has 5w/20 in it right now. Would you recommend and oil change to 10w/30?

[Jason @ 281m]

5w20 is a bad idea even for a naturally aspirated / stock compression Mustang, but its recommended by Ford for gas mileage. It does not give the best longevity to engines. We have found over the years, along with other engine experts on the 3v engines have all attested to 10w30 having the best wear characteristics. Like many PJ's, rings have a tendency to be an issue along with factory oil pumps.

[JUSTTOHAVE]

I understand, thank you for your help.

[Jason @ 281m]

Originally Posted by JUSTTOHAVE

I understand, thank you for your help.

No problem at all. If you need any work down we are just located in SOCAL and getting the car down here is about $250, its pretty cheap.

[Aussie-Parnelli]

Hi Jason

You know in the 12 years of owning the 3 valve engines this is the first time I have heard about the 5W 30 even looking on the internet there is no mention of this.
When did you realise this was a problem

Tony

[Jason @ 281m]

Originally Posted by Aussie-Parnelli

Hi Jason

You know in the 12 years of owning the 3 valve engines this is the first time I have heard about the 5W 30 even looking on the internet there is no mention of this.
When did you realise this was a problem

Tony

Hey Tony,

I never mentioned anything about 5w30. What my recommendation was is to use 10w30 on a Superchargered or high compression engine. I would even say that if you drive hard, 10w30 is the way to go.

[2007-52]

I run 10w40 in mine. I have a stroked (302) s/c 3v. I believe that was the recommended weight oil from Saleen in the owners manual supplement for the 302 "Extreme" cars.

OP... How many miles are on your engine?

Sent from my SM-G965U using Tapatalk

[JUSTTOHAVE]

88k on the odometer.