Oil pressure suddenly dropping

[Fox2506]

Aside from my starting issue, I have this:

When I put in the Stage II engine, I went synthetic. I know the oil pressure gauge is wonky but it always read really low at idle, and really high when driving.

Now after a recent oil change, the pressure drops off at idle and the engine heats up fast. Oil light comes on flickering too. Months ago it seldom did this but never heated up.

Could it be a bad/clogged oil filter or something? Or maybe I somehow after 50 oil changes I forgot to put enough oil in this time. I think it currently has 7Qt Castrol Syntec 10w/40 (maybe 30) and a bosch filter from DMCH. No drips or smells.

Like I said, I'm miles away right now and have a short window coming up to jump on this. I really hope this 2 year (+30 year) old engine doesn't have a more serious problem.

Thanks for any input

[Bitsyncmaster]

Sounds like you had poor oil pressure with heavy oil and now with the thin oil it's worse. Go back to 50 weight oil until you can get it fixed. My guess would be your oil pump needs replacement.

[DMCMW Dave]

The gauges are notoriously inaccurate but the light coming on is a very bad sign as the light will come on at something like 5 PSI. The light coming on is a genuine problem. A plugged oil filter will not cause low pressure, the filter is AFTER the pump. The only things that can cause low pressure are:
--bad pump
--plugged suction intake
--broken/collapsed/missing o-rings in the pickup line - there are three - one between the lower engine girdle and two on the pickup tube itself.

IMO (not to start a religious war) 10W-anything is too light for this engine unless it's the middle of winter. Certainly too light in North Carolina as you never have real winter. Was it a new crate engine or an upgraded stage 2?

I'd suggest that you put a mechanical gauge on it, but I do suspect you have a genuine problem with the pump. Which would be very unusual on a low mile well-maintained engine.

[deloumis]

Check your oil, make sure you don't have fuel mixed in. Gas in your oil will thin it out causing low pressure and also cause your engine to heat up rather quickly.

[DMCMW Dave]

Check your oil, make sure you don't have fuel mixed in. Gas in your oil will thin it out causing low pressure and also cause your engine to heat up rather quickly.

Good catch - I missed his "starting problem" comment, which can easily lead to flooding/gasoline in the oil. Gas in the oil can cause astounding levels of damage very quickly.

[Fox2506]

Yeah this makes sense.

It is a Stage II crate engine from 2010, put in to replace a worn out junkyard 3.0 liter Volvo block (put in by a PO).

I already have a VOD leak, but I never imagined the oil pump could be next... My books are at home, can I just drop the oil pan and swap it out? If there's no gas in the oil.

Plus I may be wrong, it could be 5 weight--this is all off the top of my head.

[Fox2506]

Ok, you were right. I'm back with the car and working on it. The oil smells like gas.

Plus I now understand that synthetic is not recommended for these engines.

I left my drain plug tool. Anyone know how to get the plug out without it?

[DMCMW Dave]

I left my drain plug tool. Anyone know how to get the plug out without it?

Make one. Either bend some 5/16 bar stock or ground down an allen wrench. Avoid the temptation to us a chisel. We see that ALL the time and the plug won't seal after that treatment. The hole is really 8 mm square.

[Fox2506]

FIXED

changed oil to Castrol 20w50 (as I should have before).

Oil pressure is way up at idle, no light. whew

[deloumis]

FIXED

changed oil to Castrol 20w50 (as I should have before).

Oil pressure is way up at idle, no light. whew

What's the reason you had fuel in your oil? Keep an eye on your oil pressure gauge, and make sure it doesn't happen again. You wouldn't want to make a small problem into a costly one.

[Iznodmad]

I was able to swing by Walters house with the snap-on brand part so he didn't have to mar his drain plug up. It was a beautiful afternoon for working on DeLoreans.

[DMCMW Dave]

What's the reason you had fuel in your oil? Keep an eye on your oil pressure gauge, and make sure it doesn't happen again. You wouldn't want to make a small problem into a costly one.

The "starting problem" he alluded to at the beginning. Often a starting problem will keep firing the cold start valve and flood the engine and dilute the oil.