Lately I've noticed my oil pressure light coming on too much. It'll stay on for about 3 seconds once I crank the car, which it didn't used to to and when I hit the brakes even halfway hard it'll come on and stay on for a few seconds after i let off. What is my latest issue in my line of issues here? Anyone?

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Red 1986 SC, 2.8L, rebuilt 700R4, 3.42, t-tops, 169K miles and counting, K&N air filters w/ removed air baffles, hopefully more to come!
RIP #3

 

Did you do the obvious, check the oil. Low oil will cause low oil presure. If the oil is fine I would swap the oil sensor. They are pretty cheap. I paid $7.00 for mine.

 

Well the K.I.S.S meathod requires this one, Are you full of oil? After that is your sending unit leaking?(like they all don't) Is the oil passage TO the sending unit have crusty buildup preventing accuate readings? How many miles? and are you hearing lifter knock? If you hear lifter knock it's the mighty death noise. Oil pump. Otherwise it will be something pretty simple. Whens the last time you ran a good oil flush through your system before the oil change? I tend to run it about every other oil change personally. I have 110K and runs great.

 

Lifter knock... You know, after hearing that phrase, I'm about 90% sure I have that. Is it a knocking noise with a slight slush to it? Like pistons pushing through slush or muck or something? I get that constantly during idle..makes the car sound like crap, along with the squeals from my belts...or something else.

 

PS-My oil PSI isn't dangerous, but it is very close.. It's typically around 25, but jumps EXTREMELY erratically between 20 and 40. That's on a warm idling engine that is..cold, the oil pressure is steady at like 55 psi. Once it warms up, it turns to crap. My assumption is that my low oil psi is from my leaks: valve covers, intake manifold, oil pan gasket, and rear main bearing seal.

 

lifter knock is a fast ciking noise, but it wont get faster if you hit the gas, just louder. If the sounds speeds up when you hit the gas it may be a rod.

 

Oh..well, in that case, I don't have lifter knock. Doesn't sound like a piston knock either though..it's so quiet and sloshy, not banging.. But yeah, when the engine speeds up, it speeds up to match the engine rpm's. Anything else that could be knocking besides the pistons? Because if it's the pistons, I'm gonna be REALLY pissed...

 

Probally it could be a valve,or the spring,that would be my last guess for it.

 

Hell it might even be the oil pump giving up. With the oil presure going up and down like that. I would replace the snesor first just to make sure thats not the problem and it's cheap.

 

So ya don't think all the leaks would cause psi fluctuations like that? The only time the pressure is steady is on a cold engine, mind you.

 

You would think the leaks would only cause low presure, but it's a good idea to fix the leaks. Less money wasted in the long run and if they are that bad it may cause the psi to go up and down. How much oil does it drop in a day?

 

The leaks do not cause as much pressure drop as you think unless it coming from the presurized side. Most "drip" leaks are just residual oil seeping out. as far as the "knocking" sound, can you narrow down the area its coming from? A good way is a long solid piece of metal. Put one end on the part you want to listen to the other to your ear. Just like a stethiscope. I have found bad bearings that way.

But if its a rod making the noise prepare for replacement, cause its gonna fly. bearing is the same.

 

It'll make a decent sized puddle...but it's not exactly a predictable leak. It has its good and bad leak days. Typically, it'll leak out a quart of oil every week and a half to two weeks. And I'll have to try the stethescope thing..never thought of that. All I can say right now is that it isn't a hard banging like a piston or anything..it's a soft mushing chug sound. Very quiet too.. The only way I could tell it was speeding up with the engine was by turning the radio off and slowly accelerating through a parking lot.

 

Timing chain shot.
Distributor leakage.
Leakage from the balancer.
All common ailments.
Many of these are very easy to "fix" if you do yourself.
And it's worth it, too.
These engines last quite a bit of milage.
AND any new stuff you put on can be swapped over to a rebuilt engine, too.
Use long screwdriver, drive car long time (warm up stretch the parts out), listen to noise thru screwdriver handle.
If ya farm out he work, tho, it can get expensive.

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Chat Soon,
KED85
Karl
1985 Firebird 2.8 to 3.4 swap project for Smog Happy LA, CA