engine tapping
engine tapping
anyone else have this issue? every time i start my xf after sitting for at least 2 hours the lifters tap for a few seconds at start up. i've checked the oil repeatedly and its ok. is this normal? will this cause engine damage? should i get it checked out? any info would be helpful... thanks.
Re: engine tapping
Noisy valves in this engine is common especially at start-up. The oil pools in the sump and takes a few seconds to start flowing thru the system when the oil pump kicks in. It'll be fine providing you don't make it a habit of revving the engine alot right after start-up. Give it a good minute warm-up before heading off down the highway.
Re: engine tapping
Originally Posted by benjiboy64
anyone else have this issue? every time i start my xf after sitting for at least 2 hours the lifters tap for a few seconds at start up. i've checked the oil repeatedly and its ok. is this normal? will this cause engine damage? should i get it checked out? any info would be helpful... thanks.
In the past I've always changed my oil around 3k, and it never made a sound before.
I changed my oil & filter, and I'm going back to the 3k oil change interval.
So I guess I'll see if this makes a difference.
Re: engine tapping
i bought this xf at 16,000, it has always done this, even after a fresh oil change...every 7,000 miles here. i know how the oil sits in the oil pan and the lifters dry out from sitting. just wondering if this will eventually damage the lifters. when i start it i don't go anywhere til the engine revs down on its own, about 30 to 60 seconds. anyways, just curious...BTW love this board!! you all are great!!...benji
Re: engine tapping
Originally Posted by lochmoy
I could be mistaken, but I thought our engine had overhead cams and therefore has no hydraulic valve lifters...only rocker arms/lash adjusters???
"Lightweight hydraulic adjusters in the rocker arms at the valves take up valve clearance for quiet operation. For minimum weight and maximum rigidity the compact rocker arms are pressure-cast aluminum. They pivot through roller bearings on rocker shafts bolted to the heads. Using computer-aided measurement and calculation techniques, valve dynamics are equivalent to that achieved by direct valve actuation through in-line tappets, but with far less friction."
Re: engine tapping
Originally Posted by lochmoy
Ingenious...I was envisioning the type of lifters in the old V-8’s that lost oil pressure and clattered away until they pumped up. Thanks for the info.
Re: engine tapping
I've noticed my XF making this tapping sound since I bought it (40k+ miles ago). I check my oil every time I fill up with gas and it's never been low on oil but I'm wondering if the tapping has something to do with the very low visc oil that is recommended? I haven't tried anything other than Mobil 1 0W40 but several people have mentioned to me that switching to a slightly heavier oil might help reduce the noise?
Anyone else have any thoughts on this or tried anything that worked to reduce the tapping sound? It doesn't bother me, I'm just curious.
Anyone else have any thoughts on this or tried anything that worked to reduce the tapping sound? It doesn't bother me, I'm just curious.
Re: engine tapping
Originally Posted by benjiboy64
anyone else have this issue? every time i start my xf after sitting for at least 2 hours the lifters tap for a few seconds at start up. i've checked the oil repeatedly and its ok. is this normal? will this cause engine damage? should i get it checked out? any info would be helpful... thanks.
Re: engine tapping
Hydraulic Valve Lifters
A device that eliminates the need for mechanical clearance in the valve train of internal combustion engines. Clearance is normally required to prevent the valve's being held open and destroyed as the valve train undergoes thermal expansion. However, clearance requires frequent adjustment and is responsible for much operating noise. The hydraulic lifter is a telescoping compression strut in the linkage between cam and valve, consisting of a piston and cylinder (see illustration). When no opening load exists, a weak spring moves the piston, extending the strut and eliminating any clearance. This action sucks oil into the cylinder past a check valve. The trapped oil transmits the valve-opening forces with little deflection. A slight leakage of oil during lift shortens the strut, assuring valve closure. The leakage oil is replaced as the spring again extends the strut at no load. See also Valve train.
Positions of the hydraulic valve lifter, with engine valve (a) open and (b) closed. (After W. H. Crouse, Automotive Mechanics, 5th ed., McGraw-Hill, 1965)
Read more: http://www.answers.com/topic/hydraulic-valve-lifter#ixzz1cYOOD6zF
Re: engine tapping
Don't know if this applies, but I had same issue on my '89 Probe, it too is 3 valves per cyl with SOHC :
Problem there was the tiny little holes in the rocker arms that supply oil to the hydraulic lifters can easily get clogged up, resulting in valve clatter, however this clatter does not go away.
Solution : remove the lifter train and rod out each lifter passage with a thin wire ( I used piano wire of the correct size ).
Worked fine on the Probe, no more lifter clatter .........
BTW, it had 106,000 miles on it .
Problem there was the tiny little holes in the rocker arms that supply oil to the hydraulic lifters can easily get clogged up, resulting in valve clatter, however this clatter does not go away.
Solution : remove the lifter train and rod out each lifter passage with a thin wire ( I used piano wire of the correct size ).
Worked fine on the Probe, no more lifter clatter .........
BTW, it had 106,000 miles on it .
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Re: engine tapping
Hey Benj,
If your lifters have gotten a little gunky, try adding some Seafoam to your crankcase. May do the trick and can't hurt the motor.
Info: Sea Foam | Tech Info - Gas Engines
If your lifters have gotten a little gunky, try adding some Seafoam to your crankcase. May do the trick and can't hurt the motor.
Info: Sea Foam | Tech Info - Gas Engines
Re: engine tapping
There have been many, many threads about this noise and this engine (and its larger cousins) in the past.
The general conclusion on this forum and on mb-world has been that the noise is normal for this engine family - there's a good bit of valve noise when the car first starts, and then a little injector + valvetrain noise when the car is running hard - it's always "clicking" a little in some way or another.
For what it's worth my '04 Coupe with just over 60k has made a little valvetrain noise at startup since I bought it at 50k, through 2 oil changes worth of the recommended 0W40 now - one when I bought it and one at 56k - so changing the oil almost certainly won't get rid of the noise. It's probably harmless, though. Again, most people with this car and its Mercedes friends hear ticking noise to some degree.
The general conclusion on this forum and on mb-world has been that the noise is normal for this engine family - there's a good bit of valve noise when the car first starts, and then a little injector + valvetrain noise when the car is running hard - it's always "clicking" a little in some way or another.
For what it's worth my '04 Coupe with just over 60k has made a little valvetrain noise at startup since I bought it at 50k, through 2 oil changes worth of the recommended 0W40 now - one when I bought it and one at 56k - so changing the oil almost certainly won't get rid of the noise. It's probably harmless, though. Again, most people with this car and its Mercedes friends hear ticking noise to some degree.
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