04 Pacifica 3.5 engine knock

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SamIam - 25 Sep 2007 20:00 GMT

I have a Pacifica with a 3.5 with 48K that has a severe engine knock when
started. The only time it does this is when it has sat for more than 3 days.

Does anyone know if this engine has a oil check valve anywhere in the
engine, or maybe in the oil filter?

Thanks is advance-

Sam

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Steve - 25 Sep 2007 21:01 GMT

> I have a Pacifica with a 3.5 with 48K that has a severe engine knock when
> started. The only time it does this is when it has sat for more than 3 days.
[quoted text clipped - 3 lines]
>
> Thanks is advance-

The 3.5 seems to do this. It also seems to not hurt it a bit. There is
a check valve in the oil filter, and on many engines using a
high-quality oil filter (Wix, Purolator, basically anything but Fram)
with a good check valve design will make a big difference in start-up
noises. It doesn't make any difference on our 3.5, so I think its
actually the hydraulic lash adjusters that bleed down and not a bearing
knock. Ours has been doing it for 246,000 miles, so it can't be terribly
harmful.

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maxpower - 25 Sep 2007 22:59 GMT

> > I have a Pacifica with a 3.5 with 48K that has a severe engine knock when
> > started. The only time it does this is when it has sat for more than 3 days.
[quoted text clipped - 12 lines]
> knock. Ours has been doing it for 246,000 miles, so it can't be terribly
> harmful.

If the noise only last for a few seconds (cold) and the vehicle was built
prior to March 31 2003 it may be due to faulty rocker arm swivels. Your
dealer would be able to verify this. But like the other reply states, if you
have an aftermarket filter with a bad check valve in it, it may be causing
the engine oil to drain back into the pan causing a lack of oil within the
engine

Glenn Beasley
Chrysler Tech

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