I recently had my intake manifold gasket replaced by my mechanic because it was leaking, and just before that, the oil pressure was reading low a little lower than usual on my truck. It still does it even after the gasket has been replaced. I did have some Cd2 put into my engine because it was making noise. I don't exactly remember the reading on the gauge, but the needle goes up to the line right before 40 psi at idle, and it goes up to the line right before 60 psi when accelerating. There are times that it goes up to 40 psi at idle, and 60 at accelerating, but most of the time it is lower than that. I have heard stories about blown engines associated with intake manifold gaskets, and therefore I am concerned. What do you guys think?

 

Don't worry, Robert, those oil pressure readings are just fine. Old 'rule of thumb' is 10 psi of pressure for each 1,000 rpm.

 

I will agree, nothing to be worried about.

The reason why engines blow due to faulty intake manifold gaskets is when the gasket allows coolant into the oil.

 

Ok, then that sounds good. Although, I was talking to someone I met today, and he told me that he had a blazer and had his intake manifold gasket replaced by his mechanic. He told me that when his mechanic replaced the gasket, they used a 3M cutting disc to shave off the old gasket. He then told me that the dust from that somehow got into the engine, and damaged the bearings. He was down in Virginia and then all of a sudden his oil pressure dropped and his engine blew. It had me thinking today because I plan on making a few trips now in the summer. lol
Another thing that I noticed, is it normal for your oil pressure to be at 60 psi as soon as you start the truck, and then after it gets warm or after you run it for a while, it goes back down to about 40 psi at idle and about 60 psi at acceleration?

 

Yes, perfectly normal. When oil is cold it's going to be thicker and pumping pressure will be higher than when it has warmed up. The mechanic in question made a mistake by using a cutting wheel to remove the gasket and by not covering the engine valley while he was working.

 

Great! Thanks a lot.

 

Ok, now I have noticed something else on the oil pressure gauge. When the Oil pressure gauge goes down to about 20 or 30 psi at idle after warming up, I have noticed that the needle bounces, back and forth as if it were twitching. I have been told that this could be a bad oil pressure switch. Is this true?

 

When was your oil last changed? My dad's explorer did that when between me and my older bro, we pushed it to 12k miles without an oil change on convential oil[:-]. Gauge started ticking back and forth (chunks of oil I'm guessing)...a couple of oil changes 500 miles apart did the trick though.

I suppose it could be just a switch/sending unit though!

 

Plus the fact that since it's an electronic gauge (opposed to a manual) there might be some electrical pulses involved. If it's just a 'little twitch' and not a 'bump', I wouldn't sweat it too much.

 

Now that you mention that, for some reason, I think it also has to do something with my sound system. Cause when I crank up the sound system, it does it more, and the oil pressure goes lower.

I really don't remember when was the last oil change, but I do know that I have been getting it done every 3,000 miles, and I have been using nothing but Castrol GTX 10W-30 High Mileage. I think the last filter I put in was an AC Delco oil filter.