Switched to synthetic...disappointed

[ramair8]

A couple weeks ago I switched from castrol gtx to amsoil, both 10w-30. I had very little if any piston slap or any other noise from my ls1. After switching to amsoil there is a very noticeable noise coming from the engine. The only reason I switched was because of everyone saying gtx creates a lot of varnish in the engine, which I did not since I plan on keeping the car for a very long time. Should I go back or give the amsoil some more time?

 

[buster]

Amsoil is a much better oil IMO and the problem with the piston slap isn't an oil issue, it's an engine problem. I'd stick with Amsoil. [ August 13, 2003, 09:24 PM: Message edited by: buster ]

 

[Al]

Are you sure it's piston slap? The GTX has moly and Amsoil doesn'but I'm doubtful that the Amsoil would cause the engine to be noisier. I'd continue with the Amsoil.

 

[wulimaster]

Did you flush before switching over or were the miles on dino really low so that a flush wouldn't be necessary?

 

[jsharp]

quote:

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Originally posted by buster: Amsoil is a much better oil IMO and the problem with the piston slap isn't an oil issue, it's an engine problem. I'd stick with Amsoil.

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Exactly. Oil isn't supposed to make up for poor assembly techniques and improper clearances. While it may "sound" worse with the Amsoil I'd bet it will do a better job...

 

[ramair8]

quote:

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Originally posted by wulimaster: Did you flush before switching over or were the miles on dino really low so that a flush wouldn't be necessary?

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No need. Car is about 2.5 years old and only has 5100 miles. [ August 13, 2003, 10:01 PM: Message edited by: ramair8 ]

 

[pscholte]

ramair8, Anything is possible with any engine, oil, and engine/oil combination, but I will tell you I have used synthetics in a Toyota, Buick, Plymouth, Mercury, Nissan, and Ford. All, for one reason or another made the switch from dino to synthetic and I have never had a complication as a result of doing that (and this was LONG before I had ever heard of or used AutoRx). I have used European and American formulations with weights ranging from 0W30 to 5W50 and in some incredibly severe operating conditions. Like I said, nary a problem. I do not believe it is the oil, but as I said at the beginning, anything is possible. [ August 13, 2003, 10:02 PM: Message edited by: pscholte ]

 

[metroplex]

Just drive it like you stole it - turn up the stereo to mask out noises. You shouldn't run into any problems this way. If you do, then it was bound to break at some point. As they say, "if it breaks, don't just fix it - upgrade it." [ August 13, 2003, 10:03 PM: Message edited by: metroplex ]

 

[ramair8]

What disappointed me was that at initial start up the noise is louder. After driving the car they sound virtually the same and it basically goes away. IF it is piston slap, I was if anything hoping it would be quieter on initial startup since the amsoil should be flowing better at initial startup. I was not saying the oil caused the noise, I think some misunderstood what I meant. What I was trying to say was that the amsoil made the noise more noticeable than with the gtx.

 

[Amkeer]

Synthetics will make the engine noise more noticeable. There is no harm in it. Drive it! Daily Drives -2003 Toyota Tacoma PreRunner XtraCab, Impulse Red, Peppy 2.7 Liter 4 Banger, Running Mobil1 Synthetics SS 5W-30. ODO 4300 Miles. -1995 Toyota 4-Runner, Evergreen, 3.0 V6, Running Mobil1 Synthetic SS 10W-30. ODO 80500 Miles.

 

[pscholte]

I guess I have been fortunate...I have NEVER had any negative changes after making the switch or even in switching weights and brands. [ August 13, 2003, 10:59 PM: Message edited by: pscholte ]

 

[JohnBrowning]

Piston Slap is a mechanical problem. No oil is going to fix a mechanical problem. SOme do a better job of masking the problem but known will fix it.

 

[Propflux01]

My question is how can an oil 'mask' a noise? slap is caused when piston hits cyl wall. if oil gets between cyl and piston, and noise goes down, that means piston is not hitting cyl quite as hard due to the cushion of oil in between, right? To me it works the exact same as a Rod bearing. No oil, and it will rattle like crazy, but with a film of oil in between rod and crank, no noise caused by metal to metal contact. What am I missing here????

 

[Mike_dup1]

LS1 engines are noisy engines! I have one, a 2002 Trans Am WS6. It made noise with the Mobil 1 factory fill in there, it makes noise with the Amsoil 10W-30 in there. Every last one I have had the occasion to observe fire up made the same noise. Piston slap, I don't know if it that or just a normal engine noise. I seem to recall back in the 60's engines were noisy due the the mechanical lifters in some hi-performance engines. No one complained it was the oil, they were proud of the noise. Today everyone expects the engine to run like a sewing machine yet run 12 sec in the quarter mile. I know many are po'd about it, but they all do it from my observation. I hear of those that claim the noise went away with that oil and this filter but I would not be surprised if it is not all wishful thinking. I say drive the car, never mind worrying about every noise you here or you are going to be doomed to a life of worrying about cars all the time. Its is not a Cadillac! Mine has 12-13,000 miles, I heard of the engine noise before I bought the car and decided I would not get po'd over it. My observation (this is what its seems to me) Some persons let things like this consume all their time. They build web pages to complain to everyone about their cars/trucks making noise, they write nasty letters to GM, and anyone else they thing will listen. The slam this product and that product. They must have nothing better to do then trying to get even over a petty issue at a vehicle, its just plastic and steel, its not a human being. Drive it and enjoy or sell it and buy a minivan. [ August 14, 2003, 08:14 AM: Message edited by: Mike ]

 

[harper]

quote:

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Originally posted by ramair8:

quote:

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Originally posted by wulimaster: Did you flush before switching over or were the miles on dino really low so that a flush wouldn't be necessary?

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No need. Car is about 2.5 years old and only has 5100 miles.

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Warranty? Take the car to a dealer and ask why the noise is there?

 

[FowVay]

Just out of curiosity, did you use the exact same type/brand of oil filter with your most recent oil change? I believe that many times the filter is the cause of varying start-up noises. As for flow differences between the Amsoil and the Castrol GTX, I don't believe there would be very much difference when measured at room temperature. The synthetic will really shine when the temperatures begin to fall but during the month of August I don't believe you'd see huge differences between synthetic and mineral flow rates. Edit: I did a quick reference glance at the specifications of the two oils and it appears that the Castrol GTX has a higher kinematic viscosity at 40 ºC; 72Cst's for the Castrol compared to 69.8Cst's for the Amsoil. This may very well have some relationship to the start-up noises that are now noticed. Of course, as the oils get hot the Amsoil carries a higher viscosity by a very large margin. I would do some curiousity testing just to see at what viscosity the start-up knock becomes inaudible. [ August 14, 2003, 08:24 AM: Message edited by: FowVay ]

 

[Mike_dup1]

quote:

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Engine Knock on Cold Start 1999-2002 Chevrolet and GMC C/K Pickup and Utility Models 2002 Cadillac Escalade (2WD) with 4.8L, 5.3L or 6.0L Engine (VINs V, T, Z, U -- RPOs LR4, LM7, L59, LQ4) This bulletin is being revised to add an additional engine to the models section. Some of the above vehicles may exhibit an engine knock noise that begins in the first 19,000-24,000 km (12,000-15,000 mi) of use. The knock noise is most often noticed during initial start-up and typically disappears within the first 5-30 seconds (may last longer in extreme cold temperatures). The noise is usually more noticeable on the initial start-up when the temperature is below 10°C (50°F) and may be more pronounced on the first cold start following a long trip. This noise may be caused by an interaction between carbon that has formed on the piston, the piston motion and the cylinder wall. GM Powertrain Engineering, and an analysis of engines with this condition, has confirmed that the noise is not detrimental to the performance, reliability or durability of the engine. THIS NOISE DOES NOT HAVE ANY EFFECT ON THE LONGEVITY OF ANY OF THE ENGINE COMPONENTS. Important At this time, attempts to repair this condition by replacing the engine assembly or pistons are not recommended. Please share the information found in this bulletin with customers who inquire about this condition. In the event they have additional questions or concerns, please advise your Area Service Manager.

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This is common in all GM engines

 

[Bror Jace]

ramair8, sounds like classic "piston slap." So a search on that term on this site and you'll see a handful of threads discussing it. Maybe try searching for the same term on Google? The general consensus is that it is from a worn, deformed or loose piston in the cylinder bore. When cold, this noise is most noticeable. As the engine warms up and the metal parts expand to fill up the space, the noise gradually disappears. Usually takes 3-5 minutes, depending on the start temperature ... the colder, the louder it is. "Ticking" noises which go away suddenly are usually caused by a sticking component in the valvetrain, often a lifter. I don't know if anyone has a conclusive answer as to "why," but oils with molybdenum seem to dampen or quiet it this down. UOAs/VOAs of Castrol GTX have shown moly but no Amsoil formulation has it. synthetic-shmenthatic. It may have nothing to do with the nature of the base oil and all about one particular additive. Anyway, I have yet to hear from an engine "slapping" itself to death. It's merely a minor annoyance. --- Bror Jace

 

[Schmoe]

Not trying to start anything here, but over on the oil filter section, Airborn Ranger just switched to Amsoil and is complaining about the exact same situation that is being described here, and he has a Ford. Hopefully it's just a coincidence.

 

[JWRENCH]

I have an '02 GMC with the same style of engine. I used 10w30 GTX for the first 6k miles then tried Mobil 1 10w30 for the next 5k and am now trying Amsoil 10w30. The GTX was noticably quieter than either of the two synthetics and the Mobil 1 was the loudest of the three. But on the other hand Mobil 1 gave me the best gas mileage so after I compare the analysis I just might settle on it to use from now on.