Impala 3.4 L Engine symptom

Background: 200,000 miles, engine runs great, oil change every 3,000 mi.
Recently the Impala was not driven for 2 weeks, soon after driving again the engine lifters started to clatter
I took it to my local shop & they ran a oil press check which indicated 30 psi vs the 60 psi spec, which indicated a press leak, possibly with the oil pump/ screen, or possibly the engine main bearings?
While at the shop we drained the oil ( which was about 1000 miles old), oil looked clean, changed the oil filter & put in new oil, plus a bottle of Mystic additive, with same results of clatter.
So as i see it i have three options:
Drop the oil pan, inspect the screen and/or replace the oil pump = $500.00
Replace the engine = $5,000.00 ($5,500.00) if in conjunction with pump not fixing the problem
Sell the car for a new vehicle

I’m between a rock & a hard place going forward?


You had 30psi at idle or at around 2000rpm?

I don’t have the specs for your engine, but 30psi at idle sounds acceptable

Perhaps the lifters themselves are the problem.

my car will have lifter noise if it seats more then a day or two with out been driven, but the noise goes away after running for a min. or two. oil pressure readings are funny things at 200k miles 30psi at idle is good and 60 going sown the road is great,as long as the engine is not tapping like a rod knock I would save my money. I thionk what happened was the lifters bled down from sitting for a long period of time. the oil pump could be tired. far as repaireing the car how is the rest of the car how good of shape is it in, does it have any other needs in the near future?

With 200,000 miles on the engine, what you might be hearing is a stretched timing chain rubbing up against the timing chain cover. Has anyone checked for that?


Thanks for the comments, the vehicle is in great condition in&out, that’s why i’m hanging in
Whatever caused this was due to the setup time, one day engine runs smooth, 15 days after setup the clatter. It’s as though 200,000 miles of possible particles settled down to the clog the pump filter (if low press is the culprit). The clatter is not noticeable inside the car windows up, it does appear to a tapping/ticking noise, otherwise the car runs great.
I would like to have the pan dropped just to inspect & look at the filter and anything else, but evidently there’s more to removing the pan than just bolts around the gasket area or why would replacing a pump cost $500.00, i can get all the parts for less then $100.00?

It could just be a failed lifter. If you take off the valve covers and press down on the rocker arm right over the pushrod with a screwdriver handle while the engine is running you can hear the noise change where there is a bad lifter or rocker arm.

I think I agree with Big Marc and Oldtimer. On my Olds that just gets started up once a month, once in a while the lifters will be very noisey at start up but goes away in a little bit. So maybe need to see if its all of them making noise or just a couple that aren’t getting pumped up.

“It could just be a failed lifter. If you take off the valve covers and press down on the rocker arm right over the pushrod with a screwdriver handle while the engine is running you can hear the noise change where there is a bad lifter or rocker arm.”

Kind of hard to run an engine with the coolant pipes disconnected, the plug wires off and the ignition coil removed. At least that’s what you’d have to do to remove the valve covers.

I’m not convinced that the trouble is related to the car sitting for 2 weeks. I would think the trouble would be noticed immediately after startup if the two were related. Could just be that 200,000 miles is the reasonable lifespan of engines these days and yours is developing issues.

As a mechanic there’s no way I would advise you to spend any money trying to get to the bottom of this. Any repair I would do would have no warranty given the age of the engine. Oil pressure that is below specification can be caused by many things, some of which are not able to be seen without engine disassembly. And as @Tester pointed out, the noise may not even be related to the oil pressure readings.

Thanks for the support guys, it’s great to see more options to consider.
So maybe my problem has moved from engine bottom to top? I know this is difficult to diagnose from a noise, but you have to start somewhere, preferably a path with least expenditure. My car experiences date back to working on my 1950 cars, so i am a relic who has to rely on a mechanic shop to determine what to do from here.

I have not seen one comment yet that suggests that the oil press may not be lubricating the lifters adequately causing the clatter, nor that the pressure reading is low, which is what i guessed and consequently the low oil pressure could be bleeding by worn bearings. This car has always been well maintained (oil change every 3000 mi) so bad pump, clogged screen, worn bearings was tough to imagine, i’m now leaning more towards lifter(s) as the culprit.
The situation with my local mech shop is they can only speculate what the problem could be, i would need to request them to concentrate on a lifter problem and not a 200,000 mi engine meltdown.

The oil pressure specs for your engine are 15 PSI @ 1,100 RPM’s and 60 PSI @ 1,850 RPM’s



At what engine speed does the engine have 30psi?

If you can confirm the noise is coming from the valve area, by using a mechanic’s stethoscope or just a length of garden hose, then could you just live w/it? Let it clatter if that’s what it wants to do, as long as it still runs ok. W/200K on the motor, sooner or later something will fail and the car won’t work, but when that happens, it might be something entirely different that fails. So if you fix the valve clatter now, it might do only temporary good, as that next problem will force a rebuild or a new engine anyway.