cold start engine knock 01 cobra

[kobra01]

I've read in the forums about cold start engine knock coming from passenger side of engine. Goes away after warmed up. My car has done this since day one. Finally took car to dealer with 3,000 miles on it to document the knock and fix some other stuff. Problem was diagnosed as no o-ring gasket found between header and exhaust pipe flange. Installed gasket and to my relief no more knock. I wonder if any other 01's left the factory without this gasket??? My build # is 3597.

 

[01ROCKET]

So they said it was the header gasket causing the noise.

 

[kobra01]

01rocket, not gasket between exhaust manifold and engine block, but exhaust manifold (collector end) and exhaust pipe flange. The knock sounded like metal hitting against the valve cover or something. I just assumed it was the same knock everybody else was talking about. Now no knock at all when i start it.

 

[01ROCKET]

The noise I get is a clack clack noise when the engine is rolling.

 

[MineralGSVT]

Originally posted by kobra01
01rocket, not gasket between exhaust manifold and engine block, but exhaust manifold (collector end) and exhaust pipe flange. The knock sounded like metal hitting against the valve cover or something. I just assumed it was the same knock everybody else was talking about. Now no knock at all when i start it.

I wasn't aware that there was a gasket there? What kind of gasket did they put in there?

My has rattled on startup since day 1 and I would love to stop it. It's kind of embarrasing starting the thing up!

Thanks..

 

[TIAMAT]

It's piston slap. A problem at startup with many cars. Maybe.

 

[kobra01]

MineralGsvt, i found my service invoice and cause was "right exhaust flange gasket leaking(never put in at factory) part# 9450 AA." Don't know if this helps you or not.

 

[pichon244]

Engine should not be knocking . . .

There's no way your engine should be knocking-----not even at the start! Let me tell you------about 5 months----my engine was knocking bad-----real badmaybe about 2 weeks after i had it serviced at the dealership. I looked at the dipstick----and it was no more than half full. The bottom line is that ford delaerships are pretty lame at caring for the vehicles. They probably had no more than 5 quarts of oil---and probably didn't run the oil through the engine when they filled it back up-----thus---the dipstick to them-----had a higher reading---when in reality the engine was 'under oiled'. Bottom line----a cobra is safe with 7 quarts. I'd never put anything less----and if you're using synthetic stuff like amsoil----u don't have to worry about it burning. I bet that engine is underoiled-----and i bet that if you been racing the car in the high rpms around town per say----then you just may have inadvertanely caused your own engine to knock. Its very likely----because those grease monkeys at the ford dealerships and plants----are pretty friction cheap when it comes to oiling the cobras!!!!

 

[brad65ford]

Well

I know of a 2001 Bullit (4,000 miles) and a 96 mistic cobra 120,00 miles that both have that knock on start up. They state thats its worse when its colder. :shrug: piston slap?

 

[pichon244]

PISTON SLAP-----DEFINETELY POSSIBLE

BUT I WOULDN'T BET ON IT------BECAUSE ALL YOU HAVE TO DO IS RACE ON THE HIGHWAY AT HIGH RPMS FOR ABOUT 5 MINUTES OR SO------WITH LETS SAY---LESS THAN 5 QUARTS OF OIL-----AND I BET YOU'LL BE ON YOUR WAY TO ENGINE KNOCK PROBLEMS--------REMEMBER------THE COBRA ENGINES ARE VERY POWERFUL-----AND IF THEY DON'T GET THE LUBRICATION WHEN THAT HEAT BUILDS UP--------THOSE 300 SECONDS-------OF UNDER LUBRICATION------REALLY CAN COME BACK TO HAUNT-------MOST PEOPLE THINK ITS NOT POSSIBLE-------BUT YOU HAVE TO REMEMBER----YOU HAVE TO KEEP THE ENGINE LUBRICATED EVERY SECOND-----AND I JUST DON'T THINK EVERY OIL CHANGE PLACE PUTS 7QUARTS OF OIL----AS THEY SHOULD BE DOING!!!!!!!!!!!! THE COBRA IS DEFINETELY A 7QT ENGINE------I'LL TAKE THAT TO MY GRAVE!!!

 

[svtduck]

Please don't shout, take your caps lock off. Thank you.

 

[brad65ford]

I'm with the duck svt guy!!!!!!!! CAPS, COME ON NOW!

 

[Vinnie T]

The cold start knock has also been traced to faulty valving in some brands of oil filters, since the system has to fill the filter to rebuild pressure. Frams are probably the worst as far as leakage past the valves. If you have even a brief knock on cold startsup, try a Motorcraft or other quality filter (AC, Mobil 1, Purolator) on your next oil change and see if it makes a difference.

 

[brad65ford]

wow!

Holy S... I would never ever guess a fliter or believed that.

 

[MineralGSVT]

Originally posted by Vinnie T
The cold start knock has also been traced to faulty valving in some brands of oil filters, since the system has to fill the filter to rebuild pressure. Frams are probably the worst as far as leakage past the valves. If you have even a brief knock on cold startsup, try a Motorcraft or other quality filter (AC, Mobil 1, Purolator) on your next oil change and see if it makes a difference.

I've used Motorcraft filters since day one and that hasn't made a bit of difference...

I even tried Mobil 1 0W-30 synthetic.. some people on corral.net had good luck with that... no help for me...

I just changed the oil tonight .. back to Motorcraft 5W-20 semi-synthetic.. and we'll see what happens..

Update: No startup rattle last night or this morning... I'm not real sure what to think.. because it always rattles in the morning..

 

[Vinnie T]

The 0W-30 will pump and build pressure faster, so I could see where that could help. As far as filters with the best anti-drainback qualities, go with the filters that have silicone valves. You can tell if they are silicone by looking at the color of the valve through the inlet holes in the filter. The silicone ones are orange in color, and don't harden and degrade over the life of the filter. You'll notice that type of valve in the Motorcraft filter.
Hope you stay rattle free from now on.