What’s making this noise?

[94CSC]

3.4L CSC. Oil pressure is great. 42,500 on the clock. Runs great but this noise is concerning. Hoping it could be an accessory. 

 

 

[55trucker]

Hmmmm......allow the engine to cool down to ambient temp, remove the serpentine belt, this will *disable* the driven accessories, fire the engine again, listen for any change, one can safely let the engine run a few minutes while the stat is still closed.

No change, then the issue is *in* the engine. What I'm hearing sounds much like clattering lifers.

What grade of engine oil are you making use of?

[94CSC]

3 hours ago, 55trucker said:

Hmmmm......allow the engine to cool down to ambient temp, remove the serpentine belt, this will *disable* the driven accessories, fire the engine again, listen for any change, one can safely let the engine run a few minutes while the stat is still closed.

No change, then the issue is *in* the engine. What I'm hearing sounds much like clattering lifers.

What grade of engine oil are you making use of?

Using 5w30. Never taken the belt off, relatively easy to do? If it is the lifters, anything to be concerned about? 

[55trucker]

Getting the belt off?...relatively easy, the easiest tool is a *serpentine belt tool kit, that will supply one with a long flat bar(lever) with the proper socket that fits over the tensioner pulley bolt head.

Even with the coolant recovery tank removed there's not a lot of space down there, using a regular 3/8 ratchet may cause scraped knuckles.

As for why the lifters are *talking to you* .....most common reason is poor oil pressure, too thin a multigrade oil etc.

When you state the pressure is good what are you basing that on?

When the engine is running at temp & idle the pressure gauge should not be lower than 25 lbs., at speed ( 2,000 rpm +) the gauge should near pegged at no lower than 60 lbs.  

 

I don't personally use oil as light as 5w30, but seeing as my car never sees cold weather it has always been run on 10w40, just offers better viscosity protection at hot temps.

 

 

 

[94CSC]

2 hours ago, 55trucker said:

Getting the belt off?...relatively easy, the easiest tool is a *serpentine belt tool kit, that will supply one with a long flat bar(lever) with the proper socket that fits over the tensioner pulley bolt head.

Even with the coolant recovery tank removed there's not a lot of space down there, using a regular 3/8 ratchet may cause scraped knuckles.

As for why the lifters are *talking to you* .....most common reason is poor oil pressure, too thin a multigrade oil etc.

When you state the pressure is good what are you basing that on?

When the engine is running at temp & idle the pressure gauge should not be lower than 25 lbs., at speed ( 2,000 rpm +) the gauge should near pegged at no lower than 60 lbs.  

 

I don't personally use oil as light as 5w30, but seeing as my car never sees cold weather it has always been run on 10w40, just offers better viscosity protection at hot temps.

 

 

 

 

Car is so hard to start and I don’t know why. Has a new starter…

 

you can see oil pressure here. Never below or above. 

[55trucker]

If one takes the *assume* approach & looks at the Cutlass pressure gauge as having the same range of motion as the GP gauge then the peak would be 80lbs. I guess that GM didn't feel it was necessary to add numerals to the gauge such as the GP pressure gauge does.

In your short video I see that the engine is cold, when starting the engine the pressure rises to a little more than 40? lbs. I don't consider that to be acceptable. The pressure relief valve would engage at somewhere over 60lbs. & your not even close to that with a cold engine.  The engine oil pressure at idle will be higher when cold than it is when hot. If the engine were developing proper pressure that gauge should be reflecting the pressure relief valve opening & closing after you start the engine & one can see the gauge constantly moving slightly back & forth as the relief valve opens & closes.

As the engine heats up one will see the pressure drop off due to internal clearances *opening up* but the pressure at idle should remain above 25lbs.

 

 

[94CSC]

Ok interesting. Can anyone with a CS with the 3.4 chime in here on where their oil pressure gauge sits and fluctuates? 

Will a heavier weight oil help with this? Any idea on why the car is so hard to start? Does the same thing hot. 

Edited October 10, 2023 by 94CSC

[94CSC]

Also reading that the oil pressure gauge on the 94's are basically dummy's and do just sit in the same spot so maybe that isn't as much of a concern? 

[55trucker]

That thought came to mind as well........the *gauge* is nothing more than a glorified *on-off* needle, remaining in the same position continually when the engine is running.

If so then one doesn't really know what sort of pressure the engine really is developing, the usual *rule -of-thumb* for a idiot light sender is 7lbs. minimum oil pressure to make the lamp go out.

A heavier weight oil would make a small difference, how much?....you would have to let us know here...but an independent stand alone pressure gauge plumbed into the gallery next to the filter would be useful to tell you just what the actual pressure really is.

As for the *hard-to-start situation*........from what I could hear I got the impression the the engine isn't firing on all cylinders. Another audio recording at the tailpipe tips would be beneficial.

If indeed the engine is firing on less than all.....you need to find out which cylinders are to blame.

[94CSC]

Sounds like I’ll need to get it into a shop to verify oil pressure. I’ll also get a recording of the tail pipes while I’m starting the car. If it’s not firing on all cylinders, could it be running on all cylinders? Asking because the car idles is perfectly and runs very strong

[94CSC]

wondering if I have a bad ignition coil and that is causing the hard start. It's also guzzling gas...maybe 150 miles on a tank, 11mpg on last fill up. 

[55trucker]

11mpg in town or on the highway?

at that rate of consumption you should see the soot in the tailpipe tips,

running rich will foul the plugs, make the engine hard to start, eventually destroy the cat.......a scanner would be very useful to you, in realtime that would display the fuel trims, the map reading, maf reading, the coolant temp reading the PCM is seeing & I would suspect that the upstream o2 would be washed with fuel & not allowing the fuel system to go *closed loop*.

 

[94CSC]

 

 

City driving. Here’s a cold start. Second start it wouldn’t fire-had to stop and start over. Maybe ignition coil?

[rich_e777]

I see a familiar puff of smoke on start up. Could have some valve stem seal issues or even a sticky lifter. With such low mileage that car must sit for long periods of time, so you might get lucky and only have some bad gas or old fuel filter. A compression test on all 6 cylinders couldnt hurt either to rule out some things.

[94CSC]

4 minutes ago, rich_e777 said:

I see a familiar puff of smoke on start up. Could have some valve stem seal issues or even a sticky lifter. With such low mileage that car must sit for long periods of time, so you might get lucky and only have some bad gas or old fuel filter. A compression test on all 6 cylinders couldnt hurt either to rule out some things.

Fresh tank of 89 in it. I’ve had car for two years, it certainly sits but not for more than a couple weeks. What do you think on the hard start?

[rich_e777]

I think its not normal but without further testing you`re asking the internet for their best guess. It could be a large number of things and testing will help narrow those things down. First thing I`d do is acquire a factory service manual that looks JUST like this.  https://www.ebay.com/itm/374819040686?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20200818143230%26meid%3D85331ef6d8ca406daf5eb047c50525f5%26pid%3D101224%26rk%3D3%26rkt%3D5%26sd%3D143356032691%26itm%3D374819040686%26pmt%3D1%26noa%3D1%26pg%3D4429486%26algv%3DDefaultOrganicWebV9BertRefreshRanker&_trksid=p4429486.c101224.m-1

Theres a flow chart in there for hard starts that takes you step by step in the process. I`ll dig mine out and get a few pics in just a bit.

[94CSC]

Thanks for this! Sounds like it could be a multitude of things that are causing the noise and the hard start issues. Might be time to get it into the shop…

[55trucker]

Just had a look  at your video, 1st thing I see when the engine does fire is the amount of black & blue smoke out the tailpipe. Black for rich, blue more than likely the oil that's being washed off the cyl's & out the exhaust as burnt oil.

You've got an over rich situation, it's not ignition, pull the plugs (the rear bank will be somewhat difficult), note which cyl each plug is pulled from, & have a good look at them, note if some are soaked & not firing, if they all are sooty then they all are firing but the fuel mixture is off.

If so  now you have to find out what has thrown the fuel mixture off normal. My last post suggests possible sensors that will do this at start up if they are out of bounds.

A failed fuel pressure regulator will cause a rich condition, raw fuel can be sucked directly into the intake manifold, you can't see the regulator as it is under the manifold plenum.

Don't throw money at the problem, get it diagnosed, then spend the money on needed parts.

Edited October 11, 2023 by 55trucker

[94CSC]

Extremely helpful, both of you! I’ll come back around and let you know what the solution is. This forum is extremely helpful.

[Schurkey]

I did not listen to the video.

GM has a bulletin on "noisy lifters".  Some '94 and '95 engines were included in that repair.  I detailed the "fix" in another long-ago post, that involves drilling, tapping, pounding-in new cup plugs, and having a machine shop rework the camshaft thrust plate since the "new, updated" thrust plate was discontinued years if not decades ago. 

http://www.60degreev6.com/vb5/articles/-1991-1997-dohc-aa/424720-lq1-service-bulletin-57-61-09-lifter-tick-cold

I performed this work on two sets of cylinder heads (actually, the camshaft carriers) and will need to do a third set next summer.

On the engine that actually runs, this "bulletin fix" made absolutely zero difference.  The real problem is piston slap.  My expectation is that the next "fix" for the lifters will also result in zero difference, the problem with that engine will also prove to be piston slap.

GM "claims" that piston slap is "harmless"; and sure enough the engine will run practically forever with the pistons clattering away.  Problem is, the pistons may knock in the bores so loudly that the knock sensor is triggered, reducing timing advance, reducing power and fuel economy in the process, and probably increasing tailpipe emissions as well.  A proper scan tool would tell that tale, by displaying knock counts as received by the computer, and the resulting timing retard.

 

Edited October 12, 2023 by Schurkey

[94CSC]

7 hours ago, Schurkey said:

I did not listen to the video.

GM has a bulletin on "noisy lifters".  Some '94 and '95 engines were included in that repair.  I detailed the "fix" in another long-ago post, that involves drilling, tapping, pounding-in new cup plugs, and having a machine shop rework the camshaft thrust plate since the "new, updated" thrust plate was discontinued years if not decades ago. 

http://www.60degreev6.com/vb5/articles/-1991-1997-dohc-aa/424720-lq1-service-bulletin-57-61-09-lifter-tick-cold

I performed this work on two sets of cylinder heads (actually, the camshaft carriers) and will need to do a third set next summer.

On the engine that actually runs, this "bulletin fix" made absolutely zero difference.  The real problem is piston slap.  My expectation is that the next "fix" for the lifters will also result in zero difference, the problem with that engine will also prove to be piston slap.

GM "claims" that piston slap is "harmless"; and sure enough the engine will run practically forever with the pistons clattering away.  Problem is, the pistons may knock in the bores so loudly that the knock sensor is triggered, reducing timing advance, reducing power and fuel economy in the process, and probably increasing tailpipe emissions as well.  A proper scan tool would tell that tale, by displaying knock counts as received by the computer, and the resulting timing retard.

 

Ah, did not know about this, thanks for sharing. Sounds like the piston slap is something that I just live with and should not impact the life of the engine. For now I will work on getting the hard start issue resolved based on feedback above. That link isn't working for me for some reason. 

Edited October 12, 2023 by 94CSC

[55trucker]

There is another outside possibility..

this engine makes use of an oil anti-drainback device to keep the oil in the cyl heads after the engine has been shut down. Because of the size of the heads & # of oil passages in them GM built in this anti drain back function.

It's called the *oil distribution cover* & it's bolted to the block in the valley area under the intake manifold.

Not knowing what that engines history is it's possible that the passages in the distribution cover are clogged and there is not enough volume/pressure delivered to the cams.

 

 

 

 

[94CSC]

Good to know. I will be taking it in to the shop soon and will let them know about this. 

[94CSC]

Took the car to the shop and just heard back. They found metal shavings in the oil filter. They removed the accessory belt, and the loud noise was still there. The engine was very difficult to turn over by hand, which could have led to the hard start issues. They have priced out a rebuilt engine, for $8500. Does that seem reasonable? 
 

Note from shop-Loud Noise Coming From Timing Belt Area, Removed Serpentine Belt To Eliminate Accessories, Noise Remained. Removed Timing Belt Cover For Further Inspection, Started To Check Camshaft Timing And Noticed Engine Was Very Hard To Spin By Hand, Loud Noise Coming From Deeper In Engine Than Timing Belt. Found Metal Shavings In Oil Internal Engine Damage. This Is Related To His Starting Issue.. Recommendation: R&R Engine Assembly

[Schurkey]

WHO is supplying this "rebuilt" engine?

I get extremely suspicious of production-line "rebuilds", too many cut corners.