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Discussion Starter #1 (Edited)
I get a knock when the engine warms up ,it doesn't seem to go up with the revs but it rattles after I rev it . The oil light doesn't turn on. Using 0w40 Mobil 1 full synthetic and K&N filter. Cleaned all sensors/throttle body ,changed the PCV and air filter. The engine doesn't knock when cold and what is weird about it is that I drove it for about 1000 miles. Another issue is that after it warms up the idle goes down to about 500rpm (AC off) .What the hell is wrong with the damn thing. This is the 2nd engine ,1st one spun a rod bearing at 145,000 miles :crying5:

Cheers guys.

EDIT: I found a random video with the same knock sound I have at idle. I don't understand the language thou @10:40 mark
 

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I'm right along there with You Bud, I'm having this problem too, I'm trying to chase it down. I don't think is rod knock, It sure doesn't sound like a Rod Knock, Just as You stated, that Knocking comes alive after the Engine warms Up and sounds is heard after You rev the engine. The knock doesn't get louder with Rev, It Just sits there and No Oil pressure light, To Me, It sounds more like top end, I'm leaning towards the Rockers, since this engine is well known for rocker arm problems. I did take My valve cover off, I wiggled all the Rockers none seem loose, The Lash Adjusters looks/seem in good condition. Funny thing is this problem started after I Changed the engine Just like You too, The Previous Engine Was Having Seizures (Vibrating like crazy when I bought it, It doesn't sound like it spun a Rod though, But, I'm not quite sure what it was) The engine did have some broken pieces/particles of some shiny (Chrome-like) looking particles in the intake..... But, anyway, moving on to this knock problem, I did a video of it if You Wanna check it out. I planned on changing the rocker arm to see if it does it, But that would be doing a blind repair (spending about $600 just for the Rocker arm assembly) that's a ridiculous amount to throw on a try and luck repair, so I'm looking to see if I can gather more info to see if I can get a close to precise diagnosis before I proceed..

But how far are You on Your quest? have You found a solution? Or is Your Problem fixed??

Vids Of Knock:



Vid Of Vibration Before Engine Swap:
Its alot worse than the video shows.. Lls
 

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And At 7:55 and 10:45 in that 1st video, He is saying something about that Timing sprocket, But, like You I cant understand WTF He's saying, and YouTube wont even let Me use their Close closed captioning.. But, I did change Mine before Installed the Engine, I thinking now it might have something to do with why its Knocking...??? :0
 

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0w-40 isn't the correct oil to use in these cars, probably why you spun a bearing. 5w-30 or 10w-30 depending on climate.

As for the sound, hard to tell on the video. Probably have to use a stethoscope to find the general area of the sound. I'd do a compression check first.
 

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0w-40 isn't the correct oil to use in these cars, probably why you spun a bearing. 5w-30 or 10w-30 depending on climate.

As for the sound, hard to tell on the video. Probably have to use a stethoscope to find the general area of the sound. I'd do a compression check first.
Yea 0W-30 Is Definitely the wrong oil to use in this Oil sensitive engine......
But, My knock sound is in the Top end, Louder/more pronounced On the Drivers Side Bank towards the back.
 

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Head or Rocker?
 

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I know this can be a touchy subject, but I don’t see why a stable (synthetic) 5W-40, or possibly even a 0W-40, would be a problem in place of recommended 10W-30. At the cold startup and final operating temperature extremes, I can only see where ‘thinner’ and ‘thicker’ (within reason of course), respectively, could only be better for engine protection - better, quicker flow than 10W-xx at dry/cold startup; higher viscosity than xW-30 at full operating temp.; similar viscosities while transitioning between cold startup and full operating temp. IMO. (And I know the laws of physics don’t care about opinions.) :)
 

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I know this can be a touchy subject, but I don’t see why a stable (synthetic) 5W-40, or possibly even a 0W-40, would be a problem in place of recommended 10W-30. At the cold startup and final operating temperature extremes, I can only see where ‘thinner’ and ‘thicker’ (within reason of course), respectively, could only be better for engine protection - better, quicker flow than 10W-xx at dry/cold startup; higher viscosity than xW-30 at full operating temp.; similar viscosities while transitioning between cold startup and full operating temp. IMO. (And I know the laws of physics don’t care about opinions.) :)
Yeah but if that were the case, then why not just put 0W in all cars? I'm not a fluid dynamics expert, but I would venture to guess that a thinner oil doesn't provide the protection necessary in an engine with looser clearances. Modern engines use thinner oils due to the tighter clearances. An engine with looser tolerances can be more reliable but less efficient and it is reasonable to believe a heavier oil would be needed in that case. It isn't always about flow. Even in my manual, it states not even to use 5W-30 in the 3.5 unless you're in a frigid climate, only 10W-30.

Just my $0.02 on that.

It is very difficult to tell over a video if it is indeed rod knock but if I had to guess, I don't think it is or at least it doesn't sound severe. It sounds like something else to me like bad compression in one cylinder.
 

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Yeah but if that were the case, then why not just put 0W in all cars? I'm not a fluid dynamics expert, but I would venture to guess that a thinner oil doesn't provide the protection necessary in an engine with looser clearances. Modern engines use thinner oils due to the tighter clearances. An engine with looser tolerances can be more reliable but less efficient and it is reasonable to believe a heavier oil would be needed in that case. It isn't always about flow. Even in my manual, it states not even to use 5W-30 in the 3.5 unless you're in a frigid climate, only 10W-30.

Just my $0.02 on that.

It is very difficult to tell over a video if it is indeed rod knock but if I had to guess, I don't think it is or at least it doesn't sound severe. It sounds like something else to me like bad compression in one cylinder.
5W-xx is much thicker when engine is cold than xW-30 is when the engine is at normal operating temp., so it should not be a problem, and again, at startup, you want the oil to get circulated to “dry” parts faster. As far as 0W-xx, I only make relatively minor deviations from the mfr’s recommendations on oil viscosity. That’s why I mentioned making adjustments “within reason”.

With non-synthetics, you didn’t want too much spread between the two numbers because to achieve wide spread, they had to load the base stock with much higher proportion of special chemicals (additives) which wore out quickly, and the hot and cold viscosity numbers were not maintained very well over the oil change interval.

With modern synthetics, that isn’t the case. The hot and cold viscosities are much more stable over the life of the oil with longer change interval, so there’s not as much reason not to go more with lower first number and higher second number. Everything is a compromise, and the greater stability of the viscosity numbers with synthetics gives more freedom to spread the gap between the numbers for better lubrication both at cold sartup and at normal operating temps. over the complete change interval. (I’m also conservative in my change intervals, because the higher stability with wider number spread only goes so far. IOW, where I used to do a 3000 to 4000 mile change interval, I now go with 5000 mi. change interval with a synthetic - none of this stretching it to 8k or 10k miles or more.)

It’s known that the recommended viscosities are a compromise between fuel mileage and wear, and they push it more to the fuel mileage side for more favorable federal mileage ratings. The consumer is educated to value fuel mileage as the only important thing, and generally doesn’t realize the compromise in the mfr’s recommendations. I’m willing to push it back more in favor of lower engine wear and longer engine life. 1/2 mpg or so loss of fuel mileage is not that important to me, whereas engine longevity is.

People should make their own decisions based on their own priorities with all the information at hand to make an informed decision.

As far as tighter tolerances of today’s engines, I used to think that was the case too, but if you look at clearances and tolerances of engines of 20 years ago compared to today, you’ll find that they really aren’t much different. Also, as an engine wears, those clearances open up a little, so that is an argument in addition to greater stability of modern synthetic oils (if you use a synthetic) for moving the second number slightly higher on a high-mileage engine. And, again with the stability of a synthetic, when you consider that the viscosity at cold startup even with a low first number (say, 5W) is much thicker than with a higher second number at normal operating temperature, there really is no reason not to move down to 5W (or 0W if you want to stretch things in that direction) with a good synthetic.

Those are my opinions, and that’s all they are, but they’re based on some solid info. and personal judgement calls. As the saying goes “YMMV” - literally. :)
 

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5W-xx is much thicker when engine is cold than xW-30 is when the engine is at normal operating temp., so it should not be a problem, and again, at startup, you want the oil to get circulated to “dry” parts faster. As far as 0W-xx, I only make relatively minor deviations from the mfr’s recommendations on oil viscosity. That’s why I mentioned making adjustments “within reason”.

With non-synthetics, you didn’t want too much spread between the two numbers because to achieve wide spread, they had to load the base stock with much higher proportion of special chemicals (additives) which wore out quickly, and the hot and cold viscosity numbers were not maintained very well over the oil change interval.

With modern synthetics, that isn’t the case. The hot and cold viscosities are much more stable over the life of the oil with longer change interval, so there’s not as much reason not to go more with lower first number and higher second number. Everything is a compromise, and the greater stability of the viscosity numbers with synthetics gives more freedom to spread the gap between the numbers for better lubrication both at cold sartup and at normal operating temps. over the complete change interval. (I’m also conservative in my change intervals, because the higher stability with wider number spread only goes so far. IOW, where I used to do a 3000 to 4000 mile change interval, I now go with 5000 mi. change interval with a synthetic - none of this stretching it to 8k or 10k miles or more.)

It’s known that the recommended viscosities are a compromise between fuel mileage and wear, and they push it more to the fuel mileage side for more favorable federal mileage ratings. The consumer is educated to value fuel mileage as the only important thing, and generally doesn’t realize the compromise in the mfr’s recommendations. I’m willing to push it back more in favor of lower engine wear and longer engine life. 1/2 mpg or so loss of fuel mileage is not that important to me, whereas engine longevity is.

People should make their own decisions based on their own priorities with all the information at hand to make an informed decision.

As far as tighter tolerances of today’s engines, I used to think that was the case too, but if you look at clearances and tolerances of engines of 20 years ago compared to today, you’ll find that they really aren’t much different. Also, as an engine wears, those clearances open up a little, so that is an argument in addition to greater stability of modern synthetic oils (if you use a synthetic) for moving the second number slightly higher on a high-mileage engine. And, again with the stability of a synthetic, when you consider that the viscosity at cold startup even with a low first number (say, 5W) is much thicker than with a higher second number at normal operating temperature, there really is no reason not to move down to 5W (or 0W if you want to stretch things in that direction) with a good synthetic.

Those are my opinions, and that’s all they are, but they’re based on some solid info. and personal judgement calls. As the saying goes “YMMV” - literally. :)
Good post. I assume when the manual said to use 10W-30, it was going by the non-synthetics back then. A full-synthetic 5W-30 may be just as good or better than a full-synthetic 10W-30. However, I still wouldn't go so low into 0W weights. I also didn't mean to turn this into an oil thread. I had a friend in high school with a 3000GT who put in a thinner oil full-synthetic and he spun a bearing, probably not related but to this day he says he thinks it's because he used too thin of an oil.

So do you recommend a synthetic 5W-30 as being the best oil for the 3.5 with higher mileage? Mine is at 131K and no signs of engine issues. I also change my oil every 2500 miles since 1) it is easy to keep track of when I have to change it and 2) Supertech oil is cheap and pretty good oil from what I've seen.
 

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Good post. I assume when the manual said to use 10W-30, it was going by the non-synthetics back then. A full-synthetic 5W-30 may be just as good or better than a full-synthetic 10W-30. However, I still wouldn't go so low into 0W weights. I also didn't mean to turn this into an oil thread. I had a friend in high school with a 3000GT who put in a thinner oil full-synthetic and he spun a bearing, probably not related but to this day he says he thinks it's because he used too thin of an oil...
Thank you for not getting irritated at my persistence. :)

I agree that I also would not go to 0W (even though I said that technically it should be OK). In fact (coincidentally, speaking of Mitsubishi), the manual for the Mitsubishi Outlander that we bought new suggests 0W-20. I use 5W-30 Pennzoil Platinum full synth. (currently at about 65k miles).

...So do you recommend a synthetic 5W-30 as being the best oil for the 3.5 with higher mileage? Mine is at 131K and no signs of engine issues. I also change my oil every 2500 miles since 1) it is easy to keep track of when I have to change it and 2) Supertech oil is cheap and pretty good oil from what I've seen.
I have been using Shell Rotella T6 (synth) 5W-40 in my LH engines starting about 6 years ago. Prior to that, I only used Castrol dino oil with 8 oz. of Marvel Mystery oil in the crankcase at all times with 50/50 mixed 15W-40 and 20W-50 to compensate for the MMO being very thin (about the consistency of ATF). Changed to synth mainly because I'm getting up in years and wanted to stretch out the oil change intervals a little.

Full disclosure: My 3.2 bit the dust at about 220k miles, likely not related to type of oil as the timing belt broke 5k miles short of a timing belt change interval, and I scrapped it. I actually think it had a lube system problem (it had a sketchy past), but I do not believe it was related to the type of oil being used. On the other hand, my 2.7 is running perfectly and very strong at about 290k miles on the same oil regimen (i.e., originally used the dino plus MMO, then switched to the Shell Rotella).
 
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