noise @ startup - should I be concerned?

[spunky]

Hi,

I drive a '99 Crown Vic w/130k. Since I changed the oil last, I've noticed a "rocking noise" during the first couple seconds of startup. The car usually does this after it's been sitting for a while. The car has not done this before (I've owned the car since 98k, have changed 7x's so far).

I've run various 5w20 oils (both syn and dino) and have never noticed this occuring. The car has consumed about 1qt per 5,000 miles. This time, I thought I'd thicken up the oil a tad. I put in 4.5 qts of 5w20 and 1/2 qt of 10w30 (what I had lying around: it was 4 qts GTX 5w20, 1/2 qt Syntec 5w20, 1/2 qt GTX 10w30).

I thought this oil combo may have created the noise, but somehow I don't believe so. I'm wondering if it's a defective oil filter, perhaps the anti-drainback valve or something. However, I can't imagine the oil seeping back into the engine since it sits in a downward position. I've used Motorcraft filters exclusively so far. The owners manual warns about using other brand filters, and I believe I remember it saying something about valve train noise @ startup.

If I leave it in until the next change, will I risk damaging the engine? The oil pressure is perfect, the engine runs smooth, and the gas mileage is still there. There hasn't been any issues with oil consumption either...

Thanks for reading my book

 

[FZ1]

When were the spark plugs last changed?

 

[spunky]

WoW, thanks for the quick reply!

I'm not sure, I picked up the car at 98k, and I haven't replaced the spark plugs (not sure if the previous owner did, haven't checked spark plug condition)

I do have a set sitting the garage ready to go though.

 

[FZ1]

Change 'em out. The better mpg will pay for the plugs and should reduce start up rough idle. .02. P.S. Don't forget the anti seize compound. Good luck.

 

[Merkava_4]

Originally Posted By: spunky
Since I changed the oil last, I've noticed a "rocking noise" during the first couple seconds of startup.


I'm not sure what you mean by "rocking noise;" can you explain further?

 

[ThirdeYe]

I'd be willing to bet it's the oil filter rather than the oil you chose... at least comparing the two, it could be something else all together.

 

[ZZman]

I would lean towards the filter also. The oil combo you did would not be a radical change that should cause that.

What filter is on it?

 

[Merkava_4]

Originally Posted By: spunky
I've used Motorcraft filters exclusively so far.


Does that mean you've always used Motorcraft up until now? What filter is on there now?

 

[aquariuscsm]

Is it upper valve train startup noise/lifter tick?

 

[spunky]

It's difficult for me to describe the noise. It's a more of a lower throaty rock rock, rather than a tick tick... LoL

I've heard this noise before after changing the oil, but not after every time I start the car. I used to have an old F-150 w/a 351 Windsor that did the same thing after a change, but not every time.

It's only for a second or two, and the engine seems to be perfectly fine after wards.

Yes, I'm still using a Motorcraft filter, sorry if that wasn't clear.

I'll take a look at the plugs during my next day off...

 

[OVERKILL]

It could be the timing chain tensioners on that 4.6. That would not have been the case on the old Windsor, likely could have been rod knock or lifter clatter.

 

[RF Overlord]

spunky, as the others said, it's unlikely that a ½-quart of 10w30 would be causing your start-up noise. Since you say it just started with this last oil change, I'd lean towards a defective ADBV in the filter. Even Motorcraft can have a bad one once in a while. Change the filter, top off the oil, and see what happens.

 

[andyd]

If it is a knock knock knock, it may be oil pressure building up in a worn main bearing. IRRC, the thrust bearing. Ive had that happen in a few old Jeep V8s. The 1.6 in my BIL's old 510 used to pound a bit on cold start ups. Both engines had a lot of miles and ran quite a bit longer. I would change the filter, maybe its a dud. If that does not cure it, try a thicker oil.

 

[jmsbntz]

Many a Crown Vic in our fleet has had similar symptoms and the catalytic converters have been the main culprit. We have only had one in two years that suffered a rod bearing failure.

Let the car cool overnight and then hit (not too hard) the converters with a soft mallet. They will rattle if they are shot. They may even rattle while hot if you are hearing the noise all the time now.

 

[Rabbler]

I was thinking main bearing knock too...

I had a few old 302 and 351 engine that did that.

 

[OVERKILL]

Originally Posted By: Rabbler
I was thinking main bearing knock too...

I had a few old 302 and 351 engine that did that.



More common in the old 302's with the non-HO firing order. The "old" firing order (same cylinder (not numerical) firing order as GM used up until the LSx engines, which is now the same as the Ford HO/351 firing order) pounds the front rod bearings.