Sorry folks if I am bringing up an old topic, but I think I may have an issue with piston slap when my engines cold and I want to get some opinions on it and its possible consequences.

I noticed I was getting a tapping/rattling noise when the engine was cold after a recent old change. Once warm the noise gradually disappears until at 3 bars the engine runs quietly.

At cold start 2000 rpm the rattle is not really audible until the tickover drops to 1000-1500 rpm when its is obvious and is heard loudest directly over the top of valve cover on every cylinder.
The valve clearances were adjusted last year so they should be ok.
I used a long screwdriver on the TCT and this was quiet so I don't think this is an issue.

An orginal USA PCX 004 filter was used at the oil change and I used 5w40 synthetic (10w30 is not easy to get here).

I have owned the car for a couple of years now and have not noticed the sound unless it was really cold (it reminds me of the rattle you get on a jap bike before its warm). The car is a 1999 but has a 2003 replacement engine, which at least in my care has never been overrevved, oil starved and has had regular servicing, so I am not sure why it has decided to become noisy.

Any ideas, suggestions would be useful. Am I being paranoid, or is it worth paying the £90 diagnosis fee (I checked) to get the dealer to see it over?

Thanks.

 

I have the same 'issue' that I've associated to piston slap. Just as you described, during cold starts it rattles around a bit. It sounds a bit like really loud injector pulsing. I think piston slap nails it as the issue dissapears quickly and doesn't return until the next cold start. I'm not concerned and I don't think you should be either.

 

Yeah, I have heard it seems normal. It just that it seems to have got considerably louder, to the point when you can hear it when you pull away in the morning for the first mile or so. And why would an oil change affect it?

 

I have the EXACT same issue with my 04 2.2L. You hear it when its cold and it disappears after it warms up.

I do only drive the car once or twice a week so the hot/cold cycles are farther apart making the noise that much more noticeable. I am always worried that the noise might not go away one of these times.....

My 04 S has 34K miles and I use Mobile 1 EP.

 

Are you sure its not the TCT?

 

TCT was changed and it didn't make a difference. It almost has the opposite symptoms of a bad TCT since the rattle is most audible when the car is cold.

 

if it is truly piston slap there isn't much you can do to solve the issue, the pistons just need to warm up and expand to fill the cylinder space.

What kind of exterior temps are you hearing this at, as most areas would be quite warm right now and this type of complaint is usually worse in cold winter conditions.

There are many engines that have this issue. I have heard of some engines having different results experimenting with different oils, but it's hit or miss until you find something that works better. If you have a chance to sign up at bobistheoilguy.com oil forums I am sure someone there will be helpful enough to provide some great advice.

 

Im in Arizona so my garage is in the triple digits all day long but the car is not driven everyday.

Im just going to put my faith in Honda and hope everything will be ok.

 

Slap can go on forever. Save your money and drive it.

 

I had a 1995 Civic DX with the B series 1.5L 4-cyl engine. Somewhere in its maintenance intensive life, it began to exhibit piston slap.

This occurs when the piston skirt wears down and when cold (and the aluminum piston is shrunken) the piston 'slaps' back and forth as it goes up and down. The noise varies with the size/type of the engine and the amount of sound deadening material under the hood, but it often sounds like a rod knock ... a fairly deep, hollow sound that varies with engine speed.

It is not a light, ticking sound at the top of the motor. That's valves (especially when maladjusted), injectors doing their thing or something else.

While a rod knock usually gets louder with engine heat (as the oil thins out), piston slap goes away after 3-5 minutes of warm-up and the aluminum piston expands and that lateral 'play' disappears.

My '95 Civic got an almost constant diet of Mobil 1. While the formulation varies almost yearly, Mobil generally believes in low levels of metallic additives in their oils (ZDDP, boron, moly, etc ...) and protection against metal-on-metal contact isn't as strong as it could be.

Also, Mobil 1 tends to be formulated on the thin side of each grade. This maximizes power and economy ... but seems to make piston slap even louder.

As noted above, piston slap is annoying. Your motor sounds like it's not going to see the end of next week ... but it's generally harmless. My Civic went 100,000+ miles after the piston slap became evident.

To minimize piston slap, you can move up in viscosity (not generally recommended) or you can use an oil high in molybdenum. In North America, the Valvoline High-Mileage oil came out about a decade ago and was VERY high in moly ... and use in winter caused piston slap to all but disappear. Same with Red Line Oil and, more recently, Honda branded oil.