Engine Rattles on Start Up

No, that's certainly not normal.

If it were the middle of winter in sub-zero temps and you were running a very heavy weight motor oil, it would be more plausible...

Is it low on oil?

ronbarb said:

I have 2001 cobra SVT with a 32 valve engine
I have always used MC5W20 blend or Mobil 1 5W20.
The engine has 50,000 gentle miles
Whenenver I start up after the engine has been sitting overnight it rattles for a 1 or 2 seconds.
No other noises once engine is warmed up.
Dealer says nothing wrong-but I have no faith in the dealer.

Is this normal for this engine?

Thanks

Click to expand...

When I first saw your post, I thought possible motor mount about to go. Now that I see what you've said I'm not sure without being there to here it. Just out of curiosity, did they check the motor mounts ? At 50k they should be okay though to be honest. Does it knock at all while your driving it under load going up a hill in say 5th gear ? I've heard that sound before when I was working for my Dad at his shop, but for the life of me, I can't recall what it was. I got rear ended on my Bike by a drunk driver and flew two lanes over into a junk yard parking lot and eight surgeries later I've got this morphine pain pump inside me that is messing with my memory. Good thing I had my helmet on that was cracked into two pieces and leathers torn to bits, yikes.
Why did I just go through all that
Sometimes engines will do that if they're out of tune as well now that I think about it. Maybe if you let the Dealer keep it over night so they can hear it / see it the first thing in the next morning, that may help them as well.

I believe what you are hearing is bearing rattle caused by loose (worn) bearings , or an oil filter that has no anti-drain back valve.
I have an 01 Cobra donor , that had been sitting for about a year that was making the noise you have described.
I looked at the filter, and it is a brand I know nothing about.

While I have the engine out of the car, I am going to pull the pan and check the bearings .
I did notice the engine had good oil pressure when running and made no noises other than the initial start up rattle after sitting.
This car also had 145.000 miles .

Are we sure this isn't the timing chains rattling? It takes a few seconds for the adjusters to pump up because they are controlled by oil pressure. If so, this is a normal engine noise.

^
That happens on my 96 as well. A second or two and they're as quiet as church mice.