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Discussion Starter · #1 ·
I have an '02 Taurus, and recently I've started hearing this low rattle type sound at low rpm - throttle tip in. To be honest, it sounds like what I remember my old F150 sounding like when I had it in fifth and wasn't going fast enough. Rattling lifters.

Do these cars have adjustable tappets? My car has 256,000 km on it, so it's no baby. I can produce this sound at any time when I hit the throttle quick and the engine is at a low rpm.

Does anyone have a picture of a 'tec with the valvecover removed?

The other thought that had crossed my mind was that maybe the timing chain is making the noise?
 

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Are you sure it's not pinging? If you let off the gas then get back on it lightly you might hear it. I get that in my 05 Freestar, and had it in my 96 Tbird. Dirty MAF was the problem. Got the appropriate cleaner, cleaned it and it went away........

If it's not that, I would suggest tapping on the cats with a rubber mallet to make sure the honeycomb isnt loose...........

MINE



This caused a ratteling noise and a tremendous amount of power loss in my sable
 

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check the heat shields, the welds rust away and cause terrible rattles.
 

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Discussion Starter · #6 ·
This is definitely a sound coming from within the engine itself... come to think of it, it could be pinging. I'll have to give my MAF a good clean!
 

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This is definitely a sound coming from within the engine itself... come to think of it, it could be pinging. I'll have to give my MAF a good clean!
Long shot but the DOHC has a knock sensor. Possible that it is not working.

Of course that is, IF the noise is pinging.

High mileage engines can have idle speed noises that are not associated with oil pressure. (That is, unlike bearings that knock until the pressure comes up). I have had that on more than on a old high miler and it was valve lifter wear. But, they just kept on and on and on, mile after mile. I put new lifters in a '87 and it quietened it down.

And I do recognize the Vulcan and DOHC are quite different, but still have lifters and cams.

-chart-
 

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Low oil pressure. Especially if it does it only with the engine warm (thinner oil).
You can test it with a real (mechanical) pressure gauge connected into the oil sender port.
In that case it might be the oil pump, it might be worn bearings inside engine... Try 5W40 oil (Roltella Shell for example) for start. Or adding Lucas (just a band-aid).

With the gauge below, if the pressure drops below first line (some 5 psi), you start to hear noises like that.
 

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Low oil pressure. Especially if it does it only with the engine warm (thinner oil).
You can test it with a real (mechanical) pressure gauge connected into the oil sender port.
In that case it might be the oil pump, it might be worn bearings inside engine... Try 5W40 oil (Roltella Shell for example) for start. Or adding Lucas (just a band-aid).

With the gauge below, if the pressure drops below first line (some 5 psi), you start to hear noises like that.
Agree.
Low pressure may not cause knock in mains or rods, not even valve lifters. But: the timing chain has a hydraulic tensioner. If you do not have sufficient pressure to keep the chain tight it will be noisy. It does not take much pressure to keep the bearings lubed at idle. Back in the day, I have seen cars, and tractors with near zero at idle still run quiet. Just so there is enough to keep it moving. Of course when you bring it up under load, there better be pressure.

The timing chain tensioner is another case. It is a pressure device, not just flow.

-chart-
 

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Discussion Starter · #11 ·
The thing is, my car drives awesome. I can only make it produce this sound with a quick stab of the throttle when it's at... say... 30 mph and an rpm well below the power band (1,000-1,500 or so). It isn't all that worrying, since it's rarely heard unless I produce it, I'm just curious as to what it could be.
 

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Well, if you don't want to hear it more often in the future you should change to a higher grade oil. If by chance you are using 5W20 now, STOP.
And switch to synthetic - it stays longer at the listed vascosity, the mineral ones degrade faster in engine.
 
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