So my more recent Fiero has a remote oil filter. I noticed recently, after changing the oil and having driven it a few thousand miles, also trying to find a leak in the set-up....that the previous owner had the hoses hooked up reversed.

So the oil was in effect coming into the "out" on the filter mount and going out the "in". So it was filtering backwards in the filter itself as well.

Though a little alarming to find this out. After correcting it, with a new filter too, all that seemed to change is the oil pressure is now 7-10 psi lower. Which is probably more accurate because it always seemed to read high, and numbers are still great.

If anyone has any thoughts or comments on this, cool.

[This message has been edited by 2.5 (edited 08-14-2017).]

I have seen fuel filters installed backwards, too. One one hand, it might be perfectly OK... On the other, who knows? Hope all is well with your engine!

OK....was the car faster in reverse...? (Sorry, just had to!)

Can't believe that someone would hook it up reversed....But then a car "Enthusiast" once asked my engine-builder friend if he needed to change his PISTONS now that his honda had 30,000 miles on it........

I suppose that the filter would (Basically) work ok in reverse....But they are supposed to have a bypass valve that would not work properly with the flow reversed....and some filters have a magnet to capture metal in the bottom...which would not work at all in reverse!

Also, if the oil filter had a anti-bleed back valve, the valve would restrict the flow of the oil

quote Originally posted by 2.5: So my more recent Fiero has a remote oil filter... that the previous owner had the hoses hooked up reversed.

OMG... some people should stick to playing video games.

All oil filters are a one way device. More so when filters have anti drain valves.
the filter media have little strength when oil flow inside to outside and can fail and block oil flow.

V6 and l4 for Fiero and others have bypass valve in the engine but many engine do not. Engine w/o bypass in them have filters w/ bypass. Bypass opens when inlet pressure is > ~4psi over outlet pressure.
Is likely the reason you had higher Oil Pressure. Bypass need pressure to open and doesn't flow as well as oil filter.

quote Originally posted by notwohorns: Also, if the oil filter had a anti-bleed back valve, the valve would restrict the flow of the oil

Many times the filter does very little to nothing and all oil will go thru bypass valve in the engine.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

The way the filter is designed, the filter should have collapsed with reverse pressure. I hope you replaced the filter when you found it was reversed, otherwise you just flushed everything back into the engine.

Video games, LOL

But....but...WAIT! Those video games are so real! I KNOW a car can flip 10 times and then land on it's wheels and continue on....withOUT dents! Yeah....that's VERY realistic.....

I'd be more worried about if there is still a filter by pass in the system, that little extra needed push to get through the filter backward might have partly or completely opened the bypass, and you had un filtered oil most of the time.
If the bypass was removed or blocked off when the remote was installed no harm, other than working the oil pump a little harder..