A new noise coming from engine compartment

[serge_saati]

Ok, it's why in your videos I noticed 2 different noises.
But even in this Windstar video 2, it's still the same as the Silverado.

Check the Silverado video at 1:44

Then check your video at 0:31

It's the same noise.

[olopezm]

I'm still hesitant to think that it sounds the same or that the problems is piston slap, man. In the GM video, there seems to be a rattling along with the tapping noise...

I've been googling it and:

1) It is a general consensus that piston slap will be louder when cold and might diminish when hot as metal expands. In my case it is the total opposite.
2) It is said that it will cause the engine to burn oil; mine does not burns a noticeable amount of oil, just the regular being pulled through the PCV valve into the upper intake (maybe a quart AT MUCH between oil changes).
3) Piston slap noise is constant and does not seems masked with higher RPM's; mine is, Sometimes I can raise the RPM's a little and the noise will return until about a second after it's back to idle speed.
4) It would also cause higher emissions because of the burning oil and lower compression. After I changed the oil and had an emissions test, all levels were lower than 6 months earlier and the guy was amazed with the results; he said to have seen newer cars with way higher values.

I'm sorry if I'm being stubborn but in this case I really don't think it is a possibility.

As always, I appreciate the help!

Oscar.

[olopezm]

I just found this video; if I had to choose, I would say that this one sounds identical to my engine (when hot) except that this one is constant and makes it even when cold. It turned out to be a lifter.

http://www.youtube.com/watch?v=yteakUCdk5I

[tempfixit]

Oscar have you by chance tested your tappet clearences while engine is running with the feeler gauge to see if that changes sounds any? I would rule out the lifters and tappets while you have the valve covers off.

[olopezm]

I haven't Larry, but I intend to as 12Ounce said in one of his recent posts. I just need some time to do it.

I'm feeling more convinced that the problem could be the lifters but I still haven't ruled out a bad timing chain tensioner as the culprit; I just don't think that piston slap could be a possibility as Serge mentioned earlier today.

Do you have any idea if oil will start spilling off from the heads while engine is running without the valve cover?

[tempfixit]

Originally Posted by olopezm

I haven't Larry, but I intend to as 12Ounce said in one of his recent posts. I just need some time to do it.

I'm feeling more convinced that the problem could be the lifters but I still haven't ruled out a bad timing chain tensioner as the culprit; I just don't think that piston slap could be a possibility as Serge mentioned earlier today.

Do you have any idea if oil will start spilling off from the heads while engine is running without the valve cover?

Yes I would plan on putting something at the lower end of the heads as oil will run off. If you have some old valve covers around cut them in half and use them or maybe makes covers out of some thin tin plating that you can bend easily. Oil should be running out of the tappets also so you could get a spray of oil there also.

[serge_saati]

Originally Posted by olopezm

I just found this video; if I had to choose, I would say that this one sounds identical to my engine (when hot) except that this one is constant and makes it even when cold. It turned out to be a lifter.

http://www.youtube.com/watch?v=yteakUCdk5I

Ok, so it's the valves lifters. And it's exactly the same noise as the Corvette engine.

[serge_saati]

Try to put a high viscosity oil treatment with cleaning additive chemical like MMO in oil to cure the sticky or blocked lifter.

Drive for few hours, then flush the oil to remove the carbon deposit.

Then use higher viscosity semi-synthetic high mileage oil with MMO additive again. Also adding a 1/2 quart -1 quart more of engine oil may help to reduce the noise.

If it doesn't work, replace the lifters, or the cam if the cam is damaged.

BTW, I found another lifter noise audio that confirm that it's the same as yours:
http://liquidintelligence115.com.au/...fter-sound.mp3

[12Ounce]

I would "prove" its the lifters before I started changing any out. Yes, using the feeler gauge while the engine is idling is a messy proposition. Plan to clean the engine box later. The noise could be something rattling about in the intake manifold.

Before going too far, I would also do compression test with all plugs removed and throttle plate held open. This is always my baseline measurement before doing anything to an engine.

I'm currently overhauling the top-end of an Escort engine that was running poorly and had metallic noises. A compression test showed I might as well remove the head, readings were all over the place. Loose valve seat was making the noise.

The problem I have with listening to these various sound files that are identified as "lifters", "chains", "piston slap" ...or whatever ... is the recorder just guessing? Or did he actually later open up the engine can correct the noise? Do they ever offer a second recording after the condition is corrected? .... I just tend to be skeptical, sorry.

[serge_saati]

The mp3 I posted come from Liquid Intelligence 115. It doesn't come from a person who has an unknow issue. Liquid Intelligence 115 sells engine oil additives that cure lifter noise. So they recorded an audio of an engine that had been diagnosed as having lifters problem. But you're right about some Youtube videos, it depends of which one.

[olopezm]

Thank you guys,

I plan on doing the feeler gauge check you mentioned 12Ounce. I found the Corvette video while googling for piston slap (thanks to Serge) and he said he had a bad lifter.

Here's the entire thread (has pictures of the bad lifter):
http://forums.corvetteforum.com/c5-t...ds-inside.html

And here's a video after installing new cam and lifters:
http://www.youtube.com/watch?v=DY8XxKU2_W8

I wonder if you know of any other product that might help, MMO is not available in Mexico and I even read that replacing 1qt of engine oil with transmission fluid would help with sticky lifters.

I can surely do a compression test, I have a tester but I must say that the engine runs great and has plenty of power; maybe an occasional misfire which I'm sure it will go away after I clean the TB.

Ig going that way, which oil weight do you think I should go with? 5w40,15w40 (the one I used before switching to 5w30).

Oscar.

[serge_saati]

10w40

[12Ounce]

An engine can run pretty well ... and still not pass a compression test.

If there is no compression variation, and the feeler gauge test reveals nothing .... its time to look elsewhere.

[olopezm]

Ok guys,

I found two things, one is the collapsed valve lifter clearance values which, I think, should give some idea (apart form inserting feeler gauges at idle) and I'm attaching the image with the procedure:



The second is quite an interesting thing; I've found that I actually have two similar noises a few milliseconds apart from each other. I was running the audio through an audio editor and realized that after listening to it at half the speed. I was trying to find a relationship between the frequency of each "tap" and the RPM's but after several simple operations I can't manage to find any, I must be doing something wrong (yeah, lazy people tend to do crazy things lol).

This is the link to my dropbox folder with the MP3 file
https://www.dropbox.com/s/v1n637rrq0...dstarNOISE.mp3

Now, I don't know what the hell would that mean but just wanted to point it out. Maybe the push rod tapping on the rocker arm and the valve stem pushing back on the rocker arm?

Oscar.

[serge_saati]

It's the half of the speed? It's very slow! I calculate only 171 beats per minutes, it's very slow. Your idle should be very slow I guess.

About the 2 noises, I think it's normal. It should be when the lifter opens and when it closes. It doesn't stay open for a long time.