Hi

In the last several months I've noticed a 'rattle' on start up.

I blew it off as possible water pump bearings, fan clutch, etc.

But, today I removed the belt and the start up noise is still there.

I've also been watching the oil pressure on start up and the gauge kicks up as normal- no drain back on filter.

Symptoms: The rattle last several seconds then phases out; and only on a cold start up, such as 8 hours or longer. If it sits, say 3-4 hours; no rattle for this shorter time period.

Thoughts?

It's an '02 4.6 with 155k miles.

Thanks

 

You wouldn't happen to be using Fram oil filters would you? If so start using the Motorcraft instead.

 

Amsoil filter.

But I'll change it out to eliminate this -- I thought about a possible defect in the check valve -- as I guess it's a good starting place.

 

Amsoil is a good filter over priced maybe but very good. How long is your oil change?

 

11k and with an Amsoil bypass.

 

Might try changing it. In the future if the noise goes away or diminishes change the filter at 5,000. also might want an oil analysis..

 

With a bypass, the oil should be good indefinitely with periodic analysis, when I was an Amsoil dealer I used to get about 60k on my oil before analysis said to change it. However, it is possible the spinon filter is faulty and draining back.

 

That's interesting. I changed the filter and sent in an UOA to Blackstone Labs.
There's Mobil One EP in there so I dumped it too. The Mobil One jug is pretty cheap at Walmart - a bit less than 6/quart. I'll use this a benchmark to find it's sweet spot. Who knows, the TBN is likely high with this setup- but not knowing I felt comfortable with the dump.

Noise is still present. I'm certain it's a timing chain type rattle. I'm guessing that the plastic guides are in tact because the noise dissipates over a 5 second span - i.e. nothing broken.

Probably more chain slack to take up or they're "lazy" from mileage wear.

Just a guess.

 

Currently, I use Mobil 1 EP and Mobil 1 filters - no bypass - and I change at 10k.

 

Just a WAG, but costs nothing to look.. Check to see if you have any busted exhaust manifold studs out of the head. Most likely the back ones on either or both sides..

Mitch