Oil pump noise?

[GrndNatnl]

Is it possible in any way for the oil pump gears to develop any play, in any direction, or make noise?

I've always had the unknown knocking noise that the car has had and been thrashed a little here and there with for almost 3 years now. It was very faint when I first got it, so I blamed the cam sensor. The noise got a little louder, so I finally replaced the cam sensor (whole assembly) with a brand new GM unit. This made a whole new different noise of its own, which quiets up after the engine warms up. But now I'm starting to wonder why.

The knocking noise is getting a little louder here recently, and I've been having some new issues with false knock / timing retard in copious amounts on certain conditions, and wondering if its related to this noise.

Under engine acceleration, it does not make a sound. Once I let go of the throttle and let it decellerate, as it passes back through the lower RPM's. If I bring the RPMs up a little and hold the throttle at a certain point, it will make this sound and remain consistant until I let it go again. I just changed the oil and started running 20w-50 for the warmer weather, and it seems a little louder, and it even does it a little while just idling.

Upon listening and poking all over the place with a stethoscope, I get a little of it from the top of the cam sensor still. But when I touched the stethoscope to something I never checked before, it was pronounced a bit more... the oil filter.

Then touching it to the oil pump housing area, I seem to hear it the most there. It's not quite as loud through the stethoscope as I would think it would be though, being that the noise is pretty damn loud just standing there listening with the hood up.

The cam sensor is still the new replaced one, and I almost switched the old one back in at one time to see if it was quieter then the new one, but I didnt.

Anyone think the oil pump might be a possibility?

 

[scottyb]

Have you replaced the timing chain and gears? I had an annoying noise that went away when I replaced the set, and I assume it was just excessive play allowing the cam sensor/oil pump to stop/start motion.

 

[GrndNatnl]

There's only ~ 40k miles on the motor. Only ~ 20k when I got ahold of it, and it was pretty faint then. Would even a crappy timing set wear out that fast?

 

[scottyb]

In that case I wouldn't suspect it, but anythings possible.

 

[GrndNatnl]

Is it worth a shot, replacing oil pump gears? I see kits that come with springs. What are the springs for?

 

[scottyb]

The spring in the pump is for max pressure relief. Don't be fooled, they don't change the oil pressure, they just set the upper threshold for instance if you rev a cold engine and the oil is cold. I think there is only one spring???? just an option on which spring to use on install??

As for replacing the gears, etc, I don't know. They don't cost much so you don't have much to lose. You should be able to inspect them upon removal and see signs of excess wear.

 

[Nick Micale]

First thing I would do is check the lower pully and "balancer". See if it loose or wobbling like the bore is worn out.

If no problem there, check crank play fore and aft to see if a thrust bearing is bad.

Next guess would be a main or rod bearing.

 

[GrndNatnl]

Nick: It's been doing it for years now. And through a good amount of racing, and even a long road trip last month, and if it were too serious, it would have fallein apart a long time ago. Thats what baffles me. I've since went by the "drive it until it breaks" philosaphy, but it's just becoming a concern again, since it seems to be a little louder, and extremely annoying. As well as the fact that its starting to do it at idle now.

I was wondering before if it could be cam walk, or somehow in relation to the cam button & spring. I have no idea anymore.

 

[texasturbo]

what about the Acc. bracket or intercooler bracket bolts??? Harmonic balancer bolt?????

 

[BoostKillsStres]

Matt, if you can get it to make the noise while your under the hood and blipping the throttle, try and push against the IC so all the brackets are loaded w/ tension and see if the noise is still there. At one time I had the lower PS IC bracket nut come loose a bit and the IC would slightly shake and rattle as you say when passing back down thru the lower RPM's from a little throttle. I thought something in the lower front of the engine was on its way out. Found and tightened the nut and no more noise, hope thats it for you too.

 

[GrndNatnl]

This noise is actually internal somewhere.

 

[65malibuss]

I have similar noise

I have a noise that's coming from my cam sensor or oil pump also.
I hear it most at idle when the engine is cold.
I used a stethoscope also and it's loudest on the cam sensor and oil filter.
I'm wondering if it's from the way the cam sensor is driven off the oil pump shaft.
I like this stethoscope, especially when I put in on an oil or trans fluid cooler line, I can hear the fluid moving.
I'm going to be listening for the same noise on other cars when I go to bowling green in 2 weeks.

 

[Red Regal T]

If you've become concerned about it, why don't you go in there and replace the timing chain set, water pump, and oil pump gears? Check for play in the oil pump gear shaft in the housing. If you replace all these parts, you'd have to stretch to spend $100. A breakdown, or serious damage to the engine, caused at the track, will be averted.