start up noise?

[Thumper_sr5]

My 2001 DOHC 4.6Liter Mustang cobra has a valve rattle noise for less then a second at every start up but worse when cold. I tried another
motorcraft FL 820 filter and 6 more qts. of M1
0w20 (last fill was motorcraft 5w20). The noise is still there but only for a spit second. After reading the BITOG filter study I'm wondering if the motorcraft filter is to restrictive on a DOHC? Anyone have any ideas? I might try a Super Tech filter next time

 

[vettenuts]

Sometimes I have some noise from my Vette on cold start, usually in the fall. I recently removed my Delco UPF44 filter in favor of the Baldwin B31 based on the study. I do notice slightly higher oil pressure and am awaiting the fall to see if the noise abates.

 

[elwaylite]

MY saturn has always done it off and on no matter what filter is in there(purolator pure one, delco, amsoil, bosch, mobil)

 

[dickwells]

You are doing everything possible to mitigate this noise. Even with the best oil/filter combination (which you appear to be using) the oil will take a small amount of time to get to the timing chain tensioners and you may hear a rattle or two until the chain tensions up. My guess is that if you do not rev it up on start you will be ok.

 

[Thumper_sr5]

I dont touch the gas on start up. I usually let the car idle 15-20 seconds before moving. I sent an e-mail to Pat goss, a local auto expert who

runs a shop that mostly sees fords. Maybe he'll know of a TSB on the car or maybe he'll say its normal.

 

[JohnnyO]

My wife's previous car (a GM) would rattle a little bit with an AC or SuperTech filter but not with K&N or Mobil 1 filters. Maybe apples and oranges but try one or both of those and see what happens. My .02.

 

[edwardh1]

my max did it with a OE filter in cold -but not with a pure one (silicone valve in pure one)

 

[Whimsey]

quote:

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Originally posted by Thumper_sr5:
My 2001 DOHC 4.6Liter Mustang cobra has a valve rattle noise for less then a second at every start up but worse when cold. I tried another
motorcraft FL 820 filter and 6 more qts. of M1
0w20 (last fill was motorcraft 5w20). The noise is still there but only for a spit second. After reading the BITOG filter study I'm wondering if the motorcraft filter is to restrictive on a DOHC? Anyone have any ideas? I might try a Super Tech filter next time

---

The time length of your noise seems normal. In fact it's quite good. At start ups it's not the flow restriction of the filter that counts but the ADBV. And the Motorcraft FL820S has an excellent silicone ADBV. As stated above being a DOHC engine with timing chains it's more likely to me slightly more noisy at start up. Just curious, what does the noise sound like where is it coming from.

Whimsey

 

[seldont]

My son and I have both owned Mark VIII s. Of course they had the DOHC 4.6. They both made the knock knock knock on start up. It was a little worse in cold weather but not much. By asking some Ford techs and visiting the Mark VIII message boards we found that it was indeed the timing chain tensioners. They are hydraulic and takes a second to build up pressure in them. Mine started at about 60,000 miles and got worse little by little until 100,000 miles or so. After that there was no change until I sold it with about 150,000 miles.

 

[Thumper_sr5]

Whimsey, Its kind of a slapping sound like piston
slap but much lighter and like I said it's gone as soon as it starts. I think Seldont has the right idea of what I'm hearing.

 

[Alex D]

It's not a valve Rattle .... the modular DOHC is known for this as stated above. It is in particluar the secondary chain tensioners being lose until oil pressure tightens them against the short secondary chains. I had good success getting this noise completely eliminated by using Amsoil S2K 0w30 with the proper Motorcraft filter