Cor ey

I have a 1997 Civic Hx and every morning when I go out and get ready for school I start up my car and it makes this awful tapping noise (along with the fan belt making a screeching noise). I was wondering if anyone knows if this is the lifter? Or could it be the oil pressure gauge not pumping oil to the injectors right away? If anyone could help I would appreciate it. Thanks.

Bror Jace

FabolusIconz,
Lemme guess, you have between 60,000-80,000 miles on your ride?

Well, let me be the first to welcome you to the "Piston Slap" zone. The side skirts on your pistons are worn and so when it is really cold out and the aluminum piston is shrunken, it is actually rattling a bit in the cylinder. This makes a noise like a classic rod knock ... except with our cars it goes away after 4-5 minutes of running. The piston expands and the noise disappears.

I used Mobil 1 in my car and when I realized the problem I had I was MAJORLY pissed and this (along with some other evidence) made me think that Mobil 1 doesn't really offer great protection, it merely flows well in the cold. I wouldn't bother with this stuff anymore.

To minimize this horrible knocking sound, you'll want to use a motor oil that has moly (molybdenum disulfide - MoS2) in it. The cheapest way to get this into your motor is to find a Schaeffer dealer (www.schaefferoil.com) and get some of their oil that has moly. They make a good dino, a synthetic blend and a full synthetic oil in 5W30. The problem is that they sell almost exclusively to shops and industry and getting them to sell directly to one person is tough.

I use Red Line Oil and that has moly in it as well but is VERY expensive. I get it for $8 per quart delivered. Some speed shops as well as a number of on-line parts places sell this stuff: auto-oil.com, myoilshop.com, manhonda.com, etc ...

Best of luck ...

--- Bror Jace

pLaYbOi

good info there bror

Rocket

Try adjusting your valve lash.

Bror Jace

Guys, valve ticking (because the lash is out of adjustment) is a totally different problem than what I had in my '95 Coupe. The noise occured when all those valves were in perfect spec.

Valve ticking usually doesn't go away when it is warm. Often, it can start out silent then get worse as the engine heats up (the opposite of the "piston slap" symptoms).

Also, a lifter or valvetrain component can stick in an engine and make an awful ticking sound and I've seen this be cured by the addition of a detergent like CD-2 or (sometimes) just a fresh oil change.

--- Bror Jace

SoloSol

I have this problem too. My car actually quits making the sound within a second after start up. I have 100k+mi. My girlfriends 92 cx makes it for about 5-10 min. but that car has 200k miles. (Its not as loud when we have fresh oil in her car)?. Is there any long term effects from this and is it going to get worse. Finally, is there any cure.

Bror Jace

SoloSol, I'm surprised you hear this sound that far south. I used to hear it only when the temp got down to 40F. And the colder it got, the louder it got. Days when it was around 0F or below zero, the car sounded like it was ready to throw a rod.

As far as I know, the Civic's engine will last a long, long time even after exhibiting this annoying symptom. It just gets louder and louder and makes your car sounder like a bigger and bigger piece of junk.

As for a real cure, you are looking at replacing all four pistons ... in other words, it's not worth it.

However, you can drastically reduce it by using a molybdenum disulfide (MoS2 - moly) based product in your crankcase. Above, I mentioned some oils that have this stuff in them but there are other products I've heard of that use MoS2 as well. Schaeffer makes a moly oil additive and someone told me that one of the STP formulas has moly in it as well. I think it's their "Oil Extender" product ... but call their 800 line to be sure. Regular STP (a polymer thickener with extra ZDDP) won't do the trick. There are others, I'm sure, but I can't think of the names off the top of my head.

I'm not sure why the moly works so well in this role other than it might form a better barrier/cushion between metal parts. It is rated for ridiculously high pressures.

If you hear a noise when you first start up and it goes away after a few SECONDS (not minutes) it might be oil starvation and NOT piston slap. What type/brand of oil filter do you use? This can cause oil starvation at start-up and will accelerate wear over the life of the vehicle.

--- Bror Jace

Rocket

Honda piston clearances are 0.0004 to 0.0016 inches new with a wear limit of 0.002. Other manufacturers are 0.002-0.003 new. Piston slap usually does not occur with these clearances.

What's happening is that when it is cold the oil takes longer to get the valve train.

I used to think my GSR had piston slap until I adjusted my valve clearances. Also try using a Honda Oil Filter.

Bror Jace

Rocket, you don't believe in Honda "piston slap"? It's well documented. Go to a number of car boards and search for the words "piston slap" and see all the cases. Honda is not the only car maker to have this problem ... which is really only an annoyance, really.

I did not believe it at first but I have seen too many cases and too many knowledeable people confirm it for it not to be true. I initially thought it was a manifold leak that disappeared as the engine warmed up and the exhaust manifold expanded to fill the gap. I have seen this sort of thing happen to 2-stroke dirtbikes where the leak is not only audible, but visible (smoke). But, I know this is no longer the case.

As for molybdenum all but eliminating the problem, I stumbled across this by accident when I switched to Red Line Synthetic oil. I have since discussed this with other guys on line and one confirmed that he had seen a study that showed molybdenum greatly reduced the piston slap symptoms in numerous engines. I never saw the study myself, only heard about it from another poster.

I can't dispute your piston clearance numbers nor how they might figure into all this. I only know that the problem is more pronounced in Hondas because they moved to a short piston skirt design and these show wear sooner than others. They did this to reduce the weight of the piston and reciprocating mass of the entire engine. A teeny bit more power, economy, blah, blah, blah ...

When my car made a racket for the first 3-5 minutes of operation, it was NOT because the oil was unable to pump through the engine. This simply can't be. Such an engine would not survive long but would seize up after only a few such starts and my car has had an additional 20,000-30,000 miles on the odometer since the symptom first appeared. Besides, my oil light doesn't stay on for more than a second no matter how cold it gets because I always used a synthetic 5W30 during the cold months. Even if I were to use a 20W50 or straight 30, the oil starvation would only last a few extra seconds, not minutes.

--- Bror Jace

Rocket

Bor Jace Cool. I live in LA and don't see low temps like you guys.

Don't rely on the oil light though. Pressure on the oil sender switch doesn't imply oil pressure elsewhere due to air pockets etc.

pornstarSR

one quick point....your fan does not have a belt....so dont let a shop try and sell you that.....its most likely your powersteering or alternator belt thats squealing

Mista Bone

Perfect! Hit that nail on the head!
Bror Jace explained it perfectly.

Bror Jace

Yes, Mista Bone might remember when I pooh-poohed the piston slap explanation on use.net ... but I eventually saw the light.

--- Bror Jace

Bror Jace

For those of you who want to eliminate (as much as possible without rebuilding) the piston slap noise that's in your engine, I found the following product for sale on the Schaeffer oil site:
http://www.schaefferoil.com/sellsheets/epoil.htm

This is their EP (Extreme Pressure) additive which uses MoS2 (moly) as its active ingredient. It's $5.50 per pint (+UPS charge) with a 4-pint minimum. If you have a buddy or two to split an order, you might want to try one of these at your next oil change. It's not inexpensive but it is cheaper than buying Red Line oil like me ... or rebuilding your motor.

It's also a cheap way to pump-up the protection afforded by these newer, emissions-friendly oils with the weak anti-wear additives.

--- Bror Jace

SoloSol

I have these symptoms when its cold(last longer and is louder) and when its warm. I run Mobil 1 5w30 synthetic and with a honda oil filter. Ill just deal with it in my car, and start looking for a D16z6 for the g/f's ride. Anyone got one for sale?