LT1Noob

I had my engine seafoamed by a mechanic, and ever since then, the oil pressure has been lower than normal. Before the seafoam, I was at about 18 psi (hot idle) and about 43 psi WOT.

Now, I am around 15 psi (hot idle), 12 psi (hot idle), sitting for a while)...but I am still at 45 psi at WOT.

I am running 10W-30 Mobile 1, and the AC Delco filter. Should I be concerned?

LT1Noob

do you think that changing the oil would be a good idea?

wile2k

I can see Seafoam lowering oil pressure by a bit. It is supposed to clean out the gunk and if some of that gunk was hindering oil flow then cleaning it out will lower the pressure.

I can't really comment on what is too low. Fully warm my psi doesn't drop below 20 (on an aftermarket oil pressure guage). How are you measuring the pressure? Stock guage or aftermarket?

mr_camaro96z28

Change the oil when the time comes there should be no reson to change early. The 15psi shouldn't hurt anything but I'm a little skeptical about the 12.

WS Sick

10 and below is when you need to worry, assuming you idle at 7-800 rpm or lower.

LT1Noob

The car idles at about 500 RPM-600 when it is hot, and there are no other signs of trouble. From what I've heard, oil pressure should be around 6psi for every 1000 RPM. Is this a gerneral statement? Does it apply to all engines?

Oh, and OP is 'normal' at anything more than idle. At 1/8 throttle, at 1200 rpm, my pressure is a little over 20 psi. Would switching to 5w-30 increase pressure? Could my oil pickup tube be clogged? Do you think that the seafoam is what is affecting the pressure?

WS Sick

youre fine then if its idling that low with that pressure. Yeah the rule of thumb is 10 psi per thousand rom, but at 5800 45 PSI will be fine.

GreenDemon

No, that's what most of the manuals say should be the minimum oil pressure for an LT1.

Keep in mind that the thicker the oil you use, the higher the pressure will be. People that use racing oils see a significant drop in pressure, so pressure that is lower than you think it should be is not always a bad sign, could just mean that things are flowing smoother now.

Unless it bottoms out or reads really low, you should be fine. Not to mention if your lifters stop getting oil, they'll let you know quickly by clattering like a sob. The timing chain in my Caddy had plastic on it to silence it, the plastic started coming off and clogged up the oil pump. Eventually the pressure went to zero and the lifters sounded like they were going crazy. Other than the cleanup of the bottom of the engine and a new chain, there was no engine damage. It's not just about the pressure, it's making sure the oil is getting where it needs to go.

WS Sick

My 93 Pontiac shop manual says 10 psi minimum at idle.

LT1Noob

This is a stupid question...but isn't it paradoxal that THICKER oil flows better? Wouldn't pressure go up if thinner oil is used?

WS Sick

I do believe that the thicker oil does not truly flow "better" but is harder to push therefore its pressure is higher.

justens95z

I asked a question on this not too long ago and nobody answered. My car is fine at idle, but at WOT it will never get above 40 psi. Someone said there was a relief valve to relieve pressure at 40 psi. Is this true? My car sees 6800 about once or twice a week, and doesn't seem like enough pressure.

WS Sick

The older pumps would stop at 40, but the LT1s pumps gain pressure with RPM. I even put the LT1s oilpump spring into my new Milodon and it behaved just like the LT1 pump. The same Milodon pump with the yellow spring in my 86 T/As 350 pumps a constant 50 psi under throttle, and sets on 20 at idle warm.