Rattling sound at start up.

[89Tona]

When ever I start my car from a cold start my engine makes a god awful rattling sound. It sounds like rocks in a tumbler. It only lasts for a few seconds and stops. The engine after that is quiet.
When driving it seems to make the same sound but not sure if I'm confusing that with the exhaust tone. Can detonation occur at start up? Anyone ever had this happen? Please, I need your help.

Kevin B

[contraption22]

What oil are you using? Does your oil filter have an anti-drainback valve? Mine used to do that in cold weather when i had 20w50 and an oversized oil filter.

[89Tona]

I'm using 20w50 now but it has done it before with different oils as well(10w40,15w30Mobile1) I have a Mobile 1 filter on there now. I'm not sure about a anti-drain back valve.
I just remembered one thing. I did here a little valve tick at S/U.

[turbovanman]

Sounds like piston or wrist pin slap. As they warm up, the clearances shrink and the noise goes away. I wouldn't worry about it, it won't damage anything.

[89Tona]

Hey, thanks guys for the replies. OK, so its nothing to worry about then. It just sounds kinda bad at Start up and wasn't sure if I needed to be concerned about it.

Kevin

[turbovanman]

Quote:

Originally Posted by 89Tona Hey, thanks guys for the replies. OK, so its nothing to worry about then. It just sounds kinda bad at Start up and wasn't sure if I needed to be concerned about it. Kevin

If you've tried different oil viscosities and oil filters and its still there then yeah, its probably what I said and its all good.

[contraption22]

If it just does it for a second or two when it's first started after sitting a while, i would say you are starving the engine for oil for the 1st few seconds. If it does it continuously until the engine warms up, then i would say it is piston slap.


Is there any particular reason you are running oil that thick?

[89Tona]

Quote:

Originally Posted by contraption22 If it just does it for a second or two when it's first started after sitting a while, i would say you are starving the engine for oil for the 1st few seconds. If it does it continuously until the engine warms up, then i would say it is piston slap. Is there any particular reason you are running oil that thick?

Yes, its just as you said. It only does it for a about two seconds. I had thought about adding a quart of slick 50 or some crap like that and see if that would stop it.

It gets hot here in Georgia during the summer and I tried 20w50 just to see if it would coat the engine better.

[turbovanman]

Quote:

Originally Posted by 89Tona Yes, its just as you said. It only does it for a about two seconds. I had thought about adding a quart of slick 50 or some crap like that and see if that would stop it. It gets hot here in Georgia during the summer and I tried 20w50 just to if it would coat the engine better.

Have you tried different oils, IE viscotiies. If its only for a few seconds, Contraption is right, its lack of oil pressure.
Slick 50 or other crap won't make any difference.

[89Tona]

Hmmm, so could this mean that my oil pump is going? I have a digital dash that I installed and the oil pressure gauge does not work so I have no way of knowing if I'm getting good oil pressure.

[turbovanman]

Quote:

Originally Posted by 89Tona Hmmm, so could this mean that my oil pump is going? I have a digital dash that I installed and the oil pressure gauge does not work so I have no way of knowing if I'm getting good oil pressure.

You keep dodging my questions, have you tried different oils, the thicker the oil, the longer it takes to circulate????????????? Try 10W30 and see what happens? Contraption also asked why you use 20W50? way to thick, your waisting HP!

Get a aftermarket oil pressure guage, the stockers are junk!

[89Tona]

Sorry, I've used Mobile 1 15w30 and Castrol 10w40, thats the only other ones I've used. I stated this in one of my posts.
I tried 20w50 just to see if it would get rid of the noise.
Yes, I plan on installing a Autometer oil pressure gauge during the holidays while I'm off from work.
10w30, I'll give it a try and see. Thanks

[Craig]

Another angle to the startup rattle.

Take a rubber mallet and while the car isn't running give the catalytic convertor (if still present) a couple of whacks. See if the monolithic block inside is broken or "rattling" around in there at all.

Later,
Craig

[89Tona]

Quote:

Originally Posted by c8r6b Another angle to the startup rattle. Take a rubber mallet and while the car isn't running give the catalytic convertor (if still present) a couple of whacks. See if the monolithic block inside is broken or "rattling" around in there at all. Later, Craig

I removed the CAT a long time ago for that reason. The blocks were broken and rattling. This noise is from the engine.

[89Tona]

This is an update on my noise problem. The knocking sound I'm getting is from the head. I removed the valve cover and started the car after it sat overnight. The noise is coming from it seems the camshaft, over the # four piston. First thing that comes to mind is the cam journals are wore out.

It takes about 30sec. for the oil to flow through the cam journals and the noise will go away. But, when I'm driving I can hear it once again.

This is a new cam that was put in this head maybe 12k ago.

Any thoughts or ideas about this? Thanks for your help.