GC and piston slap

Messages
917
Location
Singapore
I get a very minor cold start piston slap (1sec) with GC on my 2000 Suzuki Grand Vitara V6. Is that something to worry about? Should I move up to a 40wt? Other than that, the engine is smooth as silk.
 
Messages
5,358
Location
Gone
Ken4, Are you saying no other oil you have used has behaved similarly? Yours is not the first post that assigns a certain anomaly to SLX (and there are probably other brand examples). I will tell you that I do not understand how an oil with flow and viscosity characteristics shared by other oils and that performs so well in so many vehicles can all of a sudden cause noises or roughness or what have you in a specific application...unless there is something else going on. Are you sure it is piston slap? Are you sure you never heard it before? While I don't think your engine is in immediate peril, I would have a mechanic check it out, if the noise really concerns you, because what you are hearing might just be a precursor to a real problem. I think sometimes when we try a new oil, especially one with great notoriety like SLX, we listen more closely than usual and maybe hear things that have been going on for awhile but they were not noticeable enough to get our attention and then soon we became "used" to the sound...UNTIL...we try the new oil or whatever. Then we listen closely and we hear IT. I am, in no way intending to be condescending, but I can't accept that a change in brands alone can cause this, but I am open to "wisdom." I truly hope that there is indeed no significant problem with your car. [Cheers!]
 
Messages
1,565
Location
palm beach
if it only lasts for 1 second, it is not piston slap. piston slap is caused by pistons which are way undersize for the cylinder, and they basically rock in the cylinder. the only cure is heat. (well besides rebuilding the engine ) heat expends the aluminum at a quicker rate than the cylinder expands. this tightens the gap and stops the slapping. it takes alot more than 1 second for a piston to heat up enough to stop slapping, even if it is a minor problem.
 

Ken4

Thread starter
Messages
917
Location
Singapore
That's why I said it's very 'minor'. It's only on cold starts, a 1sec [Eek!] metallic clash: Ak - Ak - Ak - Ak - 'clang' - VROOMM... Hot starts, it's perfect!
 

Patman

Staff member
Messages
22,003
Location
Guelph, Ontario
That sounds like it could be a bad ADBV on your oil filter though, try switching filters to see if the sound goes away.
 
Messages
488
Location
Theodore Al
My saturn does it off and on, mainly when the temp is warm, but the engine is cold. Amsoil and GC do it less frequently than mobil, but from what i was told that 1 second sound on my car was the timing chain ratcheting up hydraulicly. I always wondered if since it only does it when its warm out, is it the fact that the oil is warmed up a bit by the heat and actually at a viscosity that is a little thick for start. For example when i crank cold at 5:30 in the morning after its been sitting there all night, no noise. When i crank it to go home at 6pm after its been sitting all day in the 100 degree heat, noise.
 
Messages
2,361
Location
Texas
quote:
Originally posted by dropitby: I thought all Forged pistons slap. [Confused]
Some do, some dont...hot rod type in an rebuild usually do, my 340 rattles and bangs pretty bad when cold till the pistons warm and it was blueprinted and honed to fit the pistons to the cylinder right in the middle of the tolerance recommended by trw. I have heard forged pistons slap so bad you could hear them over open headers on some engines. Dan
 
Messages
5,358
Location
Gone
[Off Topic!] There was a guy at the strip whose car had piston slap so bad his car sounded like a diesel and he couldn't shift to save his life. People who were there said it was the worst slapstick they had ever seen!
 
Messages
932
Location
Monroe,CT
Update.....After being shut down for 3 hours I fired her up again no noise..Go figure???Let it run a couple minutes and shut it down,45 minutes later restart,noise is back...I searched for the source,not the engine,fuel pump hums pretty good but no,it's right under drivers door in the middle somewhere...I dunno??? Gonna crawl under on sunday...Probably always there cause I have never started my truck without the radio on....I think it's just being paranoid... [Duh!] [LOL!] [LOL!] [LOL!] Good one ...
 
Messages
9,448
Location
USA
You can tell the difference between oil brands and viscositys by sound. Some oil are much better are cushioning parts then other oils. Redline oil is a good example. Redline will cut the noise of any engine you put in by 30% on average. I do not know ifit is the additives or the fact that Redline is normaly on the thick side? When I say 30% I mean as observed not measured in the inside of the car with engine running and windows up. M1 tends to be noisey.
 
Messages
932
Location
Monroe,CT
Well I just put the elixer of life,love,lubricity and truth in this morning.Upon start up there was some noise nothing alarming,then took the truck out for some errands and after the first stop and sitting for 30 minutes there was noise again..Second stop the truck was off more like an hour,noise...Last stop 5 minutes off no noise on start up...All start ups were with the window down and radio off,something I normally don't do so maybe it was there all along,but I am way way to anal about my truck not to notice such a noise..It doesn't sound mechanical like piston slap but more like mixing a 5 gallon bucket of jello with a putty knife,slurping type sound or say pouring molasses over a serpentine belt while running and the sound of a real viscous liquid squeezing through a tight spot...I can't believe using a different oil causing any noise to suddenly pop up...I'm a bit nervous but am gonna get some mileage on the oil and see what happens...Any kind words to ease my mind ???? [Frown]
 
Messages
34,215
Location
NJ
This isn't an oil problem. It's an engine problem. I wouldn't worry about it. Some oils, for reasons uknown, just have more of a tendency to muffle the noise better.
 
Messages
706
Location
Boynton Beach FL.
The use of an oil with a viscosity that is too light may result in high oil consumption. Refer to the vehicle owner’s manual for the proper oil viscosity to be used under specific driving conditions or ambient temperatures. 32 Piston Slap Some late model engines meeting the latest emission requirements have changed their piston design. This can sometimes lead to a light knock” at startup. In some cases this can increase oil consumption levels. I found this on another post and wondered what auto or truck builder changed the pistons because of emissions and now have PS. [Confused]
 
Messages
805
Location
Earth
Ken4, I have the same problem with GC in my VR6--cold starts are very metallic sounding (clack-clack-clack). I found that adding a 1/4 quart of M1 15-50 gets rid of most of the clacking (a 1/2 quart might be even better). You might as an alternative try to add a 5-7 ounces of Valvoline Synpower Oil Treatment which has a nice load of moly and boron. I just added some yesterday and will report how that goes.
 
Messages
651
Location
Punxsutawney, PA.
A one second rattle sounds like an anti-drainback valve issue in the oil filter as mentioned previously. I had cold engine noise using the GC so I switched to Chevron Supreme and it seems to be gone.
 
Messages
187
Location
Dearborn , Michigan
I agree that a 1 or 2 sec "rattle" is usually caused by a failing ADBV. In this senario the offending filter can produce noisy starts intermittently, or consecutively, and can vary throughout the life of the filter(starting off quiet then turning noisy as miles accumulate). One of my engines is particularly sensitive to filter selection, so far I have good luck with Napa Gold(Wix), maybe the silicone ADBV helps.
 
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