intermittent knocking sound at idle

[GenevaDirt]

knocking noise down low in the engine is not lifter noise. I have the same issue and they are two totally different sounds. One is a ticking and one is more knocking like you said when you first described the problem. Mine is there at idle and goes away when under load. Ticking is always there, at idle or under load.

[rmoltis]

Yes but what is this knocking sound?
I need to pinpoint its origin so I can get to fixin it.
I feel like its been getting louder/more frequent over the past 2 years.
It's really starting to bug me.
And I don't have the garage or place for a complete tear down.

[zoom zoom]

I don't think aspires have the rubber grommets for the valve cover bolts like festivas and b6's. Also wouldn't worry about a new valve cover gasket either. Some engines use a paper gasket, those need replaced, these are just a piece of rubber and as long as it doesn't dryrot I wouldn't worry too much about it. I think the issue is a lifter, but who knows. At $6 a piece and you need 8 it's a $50 gamble vs a tear down and rebuild.... At which point I wouldn't waste money rebuilding a b3 just buy a new low mileage engine.

[rmoltis]

I don't think aspires have the rubber grommets for the valve cover bolts like festivas and b6's. Also wouldn't worry about a new valve cover gasket either. Some engines use a paper gasket, those need replaced, these are just a piece of rubber and as long as it doesn't dryrot I wouldn't worry too much about it. I think the issue is a lifter, but who knows. At $6 a piece and you need 8 it's a $50 gamble vs a tear down and rebuild.... At which point I wouldn't waste money rebuilding a b3 just buy a new low mileage engine.

This will be the first place I start^
I have a full set of lifters I just ordered along with a new felpro valve cover gasket
Total was $52 for all.

For the price it seems like the best place to start.
I'll just cross my fingers and hope its not anything more major like crankshaft bearings or rod bearings.

[rmoltis]

Lifters have been installed and new gasket etc.
Drove the car a few times in the past week.
The sound is still there under the same circumstances creating the same sounds.

Now that I've narrowed down the fact that its not bad lifters.
Where is the next place I should begin???

I feel like the sound may be related to connecting rod bearings.

How simple would this process actually be.
And would just replacing them fix the problem.
Or would other work be involved say for example maybe smoothing the crank where it rubbed agInst the bearing or something???

Basically what's my next step to track down the cause of this sound?

[Bagetz]

sticky valve(s)???

[rmoltis]

I don't feel that's it.
When I have a vacuum gauge connected.
The needle stays pretty steady.

And with sticking valves it should fluctuate right?

[Team Lightning]

Are you running regular oil or synthetic? And what weight oil?

[rmoltis]

Always Mobil 1 synthetic oil.
And I run 5w30 in the winter because it gets below 0 here.
And 10w-30 in the summer cause it gets up to 100*.
But the sound is not less prevalent with either oil weight.
It still remains the same

Currently the oil weight in it is still 10w-30 because it was changed right on the cusp of the end of summer.
And still has a couple thousand left on it.
But I also have just been letting the car sit because I don't wanna drive it too often until I can at least diagnose the problem.

To be honest the 10w30 seems to work great even in 0* weather.
Within the first 5 second I can hear the oil lubricate the dry engine.
And it usually doesn't start the knocking noise until warmed up.
Although on some occasion it starts right away.

I change my oil every 3000 on the dot with a purolator filter.
Oil doesn't have any water/coolant/sludge.
Had a fine layer of micro metal particles on the drain plug magnet.
But by fine layer of micro metal. It just looked like a tiny layer of dust. No big chunks or shavings or anything weird.

And since its been the first oil change after the drain plug installation.
I have no baseline of what is normal wear every oil change yet.

[nitrofarm]

I would have bet on lifters,they are so tiny on these engines. And they clog/tick so easy in the winter.I changed out both Spire's this winter with Rock Auto cheapo's. Running 0W20 with great results,noticed a MPG improvement on the first tank. Sounds like Matt might be right? Did you ask him if it could be a wrist pin?

[rmoltis]

Yeah I thought there was a possibility it could be lifters as well.
But they make more of a high pitch ticking sound.
This sound is a lower deeper knocking type tone.

He said the wrist pin being oil squirted being clogged could be the problem and he suggested at the end of an oil change replacing 1 quart of the used oil with atf and running it for 100 miles and I went ahead and tried that before replacing my lifters to no avail.
And as much as I value Matt's opinion. And agree it could be a possible source of the problem.
A diagnosis over the phone without being able to experience the symptoms first hand.
Might lead to a different conclusion.

I'm assuming my engine is pretty clean inside with consistant oil change intervals.
As well as with the valve cover off it had a nice light golden brown color to it. With no sludge buildup.

I'm kinda hoping I won't have to completely take my engine apart out on the street lol.
Cause there are just certain things I probably can't do without a garage.

[sketchman]

Doing internal engine work with no cover sucks. Really sucks. Avoid it at all cost unless you can do it in one day and have perfect weather and good prep for everything that you might need.

I have some experience with this if you can't tell. Oh and did I mention it sucks? I had to pull and replace a head in a parking lot one cold weekend. It sucked.

[rmoltis]

^lol. Agreed.

I like to aim for the one day open/closed thing
Cause once its open.
If anything goes wrong.
Chances are its staying open for a long time.

There always seems to be unforseen variables once you get into things.

[nitrofarm]

Well the good news is these engine's are a dime a dozen.And you can swap one out in short order.

[rmoltis]

So I'd rather not replace the engine.
It is in great shape and a strong runner.
And every time I replace parts, they are in great shape.
Or the parts around are in great shape.
Mostly I just do it for preventative maintenance.

But since I don't have many other ideas to go by.
I'm gonna start with at least checking the connecting rod bearings.
Maybe the mains too.

So to check the connecting rod bearings I just.

1.) Remove oil pan and check for play in all four connecting rods.
2.) Check to see that all connecting rod bolts are not loose.
3.) If all bolts are tight and there is still play the bearings need to be replaced.

Now replacing them.
1.) Can I just replace them with stock replacements?
Or
2.) Do I have to remove the crank and have it machined and matched to a new set of spec'd bearings?

While I'm at it I would get new oil pan gasket.
And check to make sure the oil pickup screen was cleen.

And if by chance I have to machine the crank I should replace the mains as well just because.

And granted this won't happen maybe till summer.
I'd like to be prepared for my options.