Piston Slap? - Civic D15B7

[JZiggy]

Hey folks, I have a 1995 Civic with the D15B7 (16-valve 4cylinder, non-VTEC) engine. I bought it with 197,000 this Spring and now it has 204,000. So far I have done a timing belt, valve stem seals, tune-up, etc., oil changes obviously. The car runs great, has plenty of power (respectively), burns little oil and gets ~40mpg. Currently running Mobil Super 5W-30 HM w/ P1. As the weather has turned colder I have noticed a knocking noise on start-up. It is worse the colder it is outside, and gradually goes away as it warms up. This morning was the coldest it's been yet (maybe 50F) and it knocked very badly until warm-up, which took maybe 3 minutes, and then was quiet as a sowing machine. The noise is somewhat dependent upon throttle position, but it's difficult to tell exactly how. I will experiment some more with it and see if it is worse under load, deceleration, or neutral. I'm going to re-check the valve adjustment, but I have a feeling that this is not the problem as I'm pretty confidence in my valve adjusting abilities. Does this sound like piston-slap? If so, is there anything that can be done to correct it, short of a rebuild? Do you think it's best to just drive easily on it when cold and forget about the noise?

 

[A_Harman]

From the way you describe the symptoms, it sounds like piston slap. My Camaro sounds horrible on a cold start in the winter, but the noise goes away when the engine warms up. It normally takes about 5 minutes to quiet down. I have found that if the engine is revved above 2000rpm, the noise goes away, but returns when the engine goes back to idle. I don't think there is anything you can do to correct it without a rebuild. Even then, you have to be very careful about setting the piston to bore clearance. Just drive it easy until the engine reaches operating temperature.

 

[Boomer]

Try a different oil filter as well, looking for one that might give more cold flow. Try just a simple Purolator and see if that helps.

 

[Vikas]

"sowing machine"? anything to do with wild oats?? :-)

 

[Hokiefyd]

Originally Posted By: A_Harman

From the way you describe the symptoms, it sounds like piston slap...I have found that if the engine is revved above 2000rpm, the noise goes away, but returns when the engine goes back to idle.

This is the way my Honda CR-V sounds as well. I've been thinking it was a valvetrain noise (maybe a lash adjustment required), but the more I look into it, the more I think it's a cold piston slap. Seems that if I idle it around the neighborhood until I get to the main road, it'll sound rather clackity for a few minutes. But if I give it some gas, it quiets down above around 2,000 rpm. When warm, most of the noise is gone. This is the first vehicle I've ever owned that had "piston slap", so this is new to me.

 

[TomYoung]

Originally Posted By: Hokiefyd

Originally Posted By: A_Harman

From the way you describe the symptoms, it sounds like piston slap...I have found that if the engine is revved above 2000rpm, the noise goes away, but returns when the engine goes back to idle.

This is the way my Honda CR-V sounds as well. I've been thinking it was a valvetrain noise (maybe a lash adjustment required), but the more I look into it, the more I think it's a cold piston slap. Seems that if I idle it around the neighborhood until I get to the main road, it'll sound rather clackity for a few minutes. But if I give it some gas, it quiets down above around 2,000 rpm. When warm, most of the noise is gone. This is the first vehicle I've ever owned that had "piston slap", so this is new to me.

The original poster's note talks about a 200k+ car. I very much doubt that your 50K, 2008 CRV is exhibiting piston slap. If anything, it's more likely to be a noisy lifter or valve that needs a quick adjustment.

 

[OVERKILL]

Originally Posted By: TomYoung

Originally Posted By: Hokiefyd

Originally Posted By: A_Harman

From the way you describe the symptoms, it sounds like piston slap...I have found that if the engine is revved above 2000rpm, the noise goes away, but returns when the engine goes back to idle.

This is the way my Honda CR-V sounds as well. I've been thinking it was a valvetrain noise (maybe a lash adjustment required), but the more I look into it, the more I think it's a cold piston slap. Seems that if I idle it around the neighborhood until I get to the main road, it'll sound rather clackity for a few minutes. But if I give it some gas, it quiets down above around 2,000 rpm. When warm, most of the noise is gone. This is the first vehicle I've ever owned that had "piston slap", so this is new to me.

The original poster's note talks about a 200k+ car. I very much doubt that your 50K, 2008 CRV is exhibiting piston slap. If anything, it's more likely to be a noisy lifter or valve that needs a quick adjustment.

Piston slap happens on brand new vehicles. It is simply excessive piston-to-wall clearance. Has nothing to do with age or mileage.

 

[A_Harman]

Agreed. My Camaro had piston slap when it was new.

 

[Hokiefyd]

Yeah the OP's engine (as well as mine) doesn't use "lifters". They're direct cam followers. Mine has rollers, not sure about the D15 engine. Either way, in the OP's case, valve lash has already been checked. Some engines are just noted to have piston slap noises. The ones that are most notorious for it, that I'm aware of, are some GM V-8 engines and some Toyota GR-series V-6 engines. Many V-6 Camry owners complain of piston slap noises. If this is the first winter the OP has had with the Civic, and the first time he or she is using it in cold weather, it's likely piston slap (and it's likely the car's been doing it since new, or at least since very young in its age).

 

[garlicbreadman]

check teh distributor shaft for play...it will make a tapping noise which may make you think its a knock.