synthetic = lower oil pressure

[stonny9]

i just switched to synthetic in my 93 3.4 w/139000 miles and the oil pressure dropped 10-20psi. now it idles at about 30psi used to be 40psi and cruise at about 45psi used to be 60-70psi. would this be an indication of a problem or something i should worry about and if so what should i do?

[Ian]

um, definately not supposed to go with synthetic after like 75,000 miles.

i dunno what happened, but you may want to check www.bobistheoilguy.com

[FunkZ]

Did you run 10w30 in conventional oil and switch to 5w30 in synthetic?

Some people have a problem with high-mileage motors after switching to synthetic oil and developing leaks. I've run synthetic blend in mine for 110k miles (bought the car with 40k) and no problems yet.

[Ian]

oops, yea, what i meant was, you shouldnt START using synthetic if your car has over 75,000. you can use it if you started before that, but like FunkZ said, if you start after that, some people have problems with leaks.

[stonny9]

no i didnt switch from 10w30 to 5w30 i was using regulat 10w30 or valvoline high mileage 10w30 then went to swnthetic. i had a leak in the oil pan gasket and the mechanic(family friend) said to switch to syntethic when he replaced to gasket. i put in valvoline high mileage syntethic 10w30 and that was 2 weeks ago and no leaks yet. yes i did read a lot of post about syntethic use and knew about the possibility of an oil leak after switching

[bu-bye]

switching from regular to syn will give you leaks. Your gaskets are used reg oil. When you start using syn after a couple years you are looking at leaks not only on the oil pan but also in the engine. I would switch back if it were my car.

To answer your question, yes I have seen syn oil have a lower PSI over reg oil. Not sure if its a bad thing. I see loss of oil PSI as a bad thing but thats just me.

[Die Ford V8]

did you have regular oil and regular pressure after your friend fixed the oil pan, or did you start with si\ynthetic right after.

maybe the friend messed it up. just a thought. good luck

[FunkZ]

Another thing to consider is if the pickup tube is too close to the bottom of the pan, oil pressure will drop. 10psi might be explained by simply going from dino juice to synthetic, however a 20psi drop is pretty alarming. Is it possible the pickup tube got bumped/bent/moved down when the pan was removed to change the gasket?

[nikon]

hmm, I look at it tottaly different...I find lower oil pressure...as long as you have no leaks...its a good sign, this means the oil is flowing very freely through your motor, and there is no blockage in any of the oil passages, my tahoe runs with very high oil pressure, BUT they all do, design flaw?...I dunno as long as your motors not leakin I wouldnt worry about it too much, just look for white smoke....if not your good... ;)

[stonny9]

syntethic oil was put in when the oil pan gasket was put in. when i started my car this morning the press was at 60psi but dropped a minute later to 40psi. isnt syntethic oil thinner than regular oil. if it is i think that is why the pressure is lower.

at the next oil change should i switch to regular oil to see what happens with the psi. if the psi stays the same and it is determined that the oil system is fine should i go back to syntethic

[nikon]

Originally posted by stonny9:
syntethic oil was put in when the oil pan gasket was put in. when i started my car this morning the press was at 60psi but dropped a minute later to 40psi. isnt syntethic oil thinner than regular oil. if it is i think that is why the pressure is lower.

the oil thickness is determined by the weight of the oil 5w-30 10w-40, and so on....I think your just fine, no worries unless it leaks

[GhostRunner]

*Sighs and facepalms*

There's no reason that a synthetic motor oil is gonna change how your engine runs in any way/shape/form no matter how many miles its got. If it's leaking oil before you switch, it's gonna keep leaking oil, if it wasn't leaking oil before, it's not just gonna suddenly spring a leak.

More than likely, something was messed up when you got the pan gasket switched like others are saying, or your oil pressure regulator is on the outs.

[MDfirebirdb]

Hey I have used synthetic after buying the car with over 90,000 miles and have no problem. While I have heard that synthetic finds leaks I have rarely seen it. I highly recommend it (Mobil one)

[stonny9]

i have noticed that while cruising it is about 50psi not as high as the 60psi i had before but still ok for me. thanks for all or your replies