Should I stay with 10W-30 or go back to 5W-30?

wtd

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2,584
Location
southwest Mo.
My 98 chevy truck with the 5.7L has quite a bit of startup knock with the Mobil 1 10W-30. I don't remember it being this bad when I ran the 5W-30. Do you think this startup knock is causing damage and should I switch back to 5W-30? Is there another brand of oil that would work better? Wayne
 
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8,711
Location
Nothern USA
I would definitely go back to the 5W-30. I have never used the Mobil 1, but many here like it. It should do a good job of protecting the engine, both hot and cold. If you feel you must use the 10W-30, I would look for a less restrictive filter. I know the AC's for my truck have more filter area than other brands. You may also look for oversizes, a PF 52?
 
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5,358
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Gone
wtd, I think I would try the 5W30 (you could even go 0W30 in your area) and a K&N filter for even better flow...you'll just be paying a good deal more than you normally do for a filter...but if it tones down the knock.... [Smile]
 
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2,556
Location
Columbus Ohio
I have a 98 GMC with a 350. I got worse tick with mobil 1 5w30, than with any other oil I have tried. I have always run a 5w30 though. I am going to assume that it is because of the lighter viscosity of mobil 1. With the RP I am running now, I get no lifter tick initially, then after a couple thousand miles, The tick returns. I am assuming that the RP is thinning out, due to the reduction in oil pressure........HOT IDLE 32 to 24.
 
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612
Location
Joplin
quote:
Originally posted by wtd: My 98 chevy truck with the 5.7L has quite a bit of startup knock with the Mobil 1 10W-30. I don't remember it being this bad when I ran the 5W-30. Do you think this startup knock is causing damage and should I switch back to 5W-30? Is there another brand of oil that would work better? Wayne
I don't think the startup knock will be any better changing to the 5w-30. The 10w-30 should flow in SWMO without any problems. I'd stay with it.
 
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82
Location
Wimberley, Texas
I am definitely with gearhead on this one.The 4.6 engine in my Town Car was at its loudest with 5w30 Mobil 1 .Terrible knocking/ticking at warm idle like at stop lights and of course on cold start up.IMHO Mobil 1 in 5/10w30 is just too light weight for most cars(and yet Ford recommends 5w20 for all these 4.6 engines young and old [Mad] )So I would change brands all together to something thicker with better additives(mobil 1 relies too much on its base stock in my opinion)
 
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5,358
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Gone
Please note, everyone, that wtd has attested to the fact that he remembers his engine being quieter with the 5W30. Maybe, for some reason, his engine just likes 5W30 better even though some of yours do not. Why would he want to stick with something that in his assessment doesn't work as well? [ October 13, 2003, 06:25 PM: Message edited by: pscholte ]
 
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9,448
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USA
Knock is a mechanical problem! Oil can not solve a mechanical issue! Even if 5W30 mask's it better the problem is still their. The difference between M1 5W30 and 10W30 are so small that they are almost insignificant in terms of the big picture. It will not hurt anything but it can not help either. The only way a thiner oil would help is if the knock was due to oil starvation. Again the only way any part could be starvin for oil with M1 10W30 in the engine is if a mechanical problem is present!
 

wtd

Thread starter
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2,584
Location
southwest Mo.
Thanks for all of the replies. I forgot to mention that the recommended viscosity for this engine is 5W-30, though you can use 10W-30 if the temperature is above 0 degrees. I use an AC-Delco UPF52 gold series oil filter. I changed to 10W-30 because I read on this site that it was better than the 5W-30. Is there really that much difference between the two? Wayne
 
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15
Location
Illinois
quote:
Originally posted by wtd: My 98 chevy truck with the 5.7L has quite a bit of startup knock with the Mobil 1 10W-30. I don't remember it being this bad when I ran the 5W-30. Do you think this startup knock is causing damage and should I switch back to 5W-30? Is there another brand of oil that would work better? Wayne
Try a different brand of filter -- one that holds its oil better after shutdown -- so that the oil pumps stays primed until the next startup.
 

wtd

Thread starter
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2,584
Location
southwest Mo.
What brand of filter would be better than what I'm already using? I've used the filter that I mentioned above since about 14,000 miles and now the truck currently has 56,700 miles on it now. The startup tapping started at about 34,000 miles. I want to clarify something about the startup noise. Its more of a "tapping" sound than a "knock". I don't know if its the lifters or not or if I have a mechanical problem. The dealer says that most 5.7L's do it eventually and that it won't hurt anything. I don't know if I believe that or not but I have heard other trucks with my same engine do the same thing. Wayne
 
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Not Seattle, but close.
I know some call the PureOne filter restrictive, but I've been using it on my Cherokee and never have any starup noise. I think all that media --or maybe the ADBV is really good--holds oil in the filter pretty well after the engine is shutdown. But what do I know?
 
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267
Location
Rhode Island
Are you sure of the source? Many fuel injectors are noisy during cold start and sound like the motor internals. Might pay to get a mechanics stethoscope and pinpoint the noise source.
 
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2,556
Location
Columbus Ohio
I have had a couple GM dealership mechanics tell me that it is a problem with the GM roller lifters used in the engine. They say that the older engines with flat tappet lifters didn't have the problem. They said that it doesn't affect durability. [Roll Eyes]
 
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94
Location
Seattle
I also agree with JB. Lifter noise and piston slap are both common to these engines, you might do well to try both a lighter and a heavier oil to better mask the problem. Perhaps go back to 5w30 if no improvement try 0w40 or 5w40, I won't hurt anything to try different weights. I have a friend with a late model Ford truck which has terrible piston slap when cold, it is far less noticable when 10w40 is used instead of 5w30.
 
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3,593
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Outside smalltown, IL
I agree with jb, it sounds like there's some mechanical issue at work here. At the same time, you've had good luck with M1 5W-30 so I see no reason not to go back to it. The slightly thinner cold viscosity can't do anything but help startup problems...
 
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2,480
We have to clarify that the problem being addressed here is a "cold start" issue, NOT tapping when the engine is hot, righ? I've had similar issues with colder temps with a 10w or 15w. From what I can ascertain, the knock is a stuck valve/lifter probably due to sludge/varnish build-up (unless it's truly mechanical wear as John suggests) and as I have experienced in such cases, a "thinner" oil help cure the noise completely...and that's the noted difference here between the 5w-30 and the 10w-30. Definately a case for auto-rx 1st. Any other way to clean the valve stems/lifters???
 
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