My 2006 4.7l dodge has 201000 miles on it runs good. No oil burning. Ran conventional oil till last oil change. Changed oil to valvoline advanced full synthetic. Sounds like a diesel when started cold, after warm up it's fine. Any thinner synthetic oil when cold to stop the cold start sound? Thank you
4.7l dodge sounds like a diesel after synthetic oil change.
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What did you put in it?
dnewton3
Staff member
1) Your first post in 13 years??? I do believe that's a new record!!!
2) you went from a conventional oil to a synthetic already in this OCI, and that presumably would be of less vis at start-up. And now you want an even thinner lube? If thin oil caused the problem (and I'm not saying that I am convinced it did), then what makes you think using an even thinner lube would make the issue go away? (We'll assume you used the same vis grade for all OCIs.)
3) perceptions of sound are easily affected by many things, not the least of which are confirmation bias, but also ambient temps, etc
2) you went from a conventional oil to a synthetic already in this OCI, and that presumably would be of less vis at start-up. And now you want an even thinner lube? If thin oil caused the problem (and I'm not saying that I am convinced it did), then what makes you think using an even thinner lube would make the issue go away? (We'll assume you used the same vis grade for all OCIs.)
3) perceptions of sound are easily affected by many things, not the least of which are confirmation bias, but also ambient temps, etc
Patman
Staff member
That doesn’t always work though, which is why a lot of high mileage engines burn oil and then see a drastic improvement when running VRP
Still valid for the OP's case as he is not burning oil.
Patman
Staff member
True, but I was speaking generally about if you are recommending to others with high mileage that they should just always stick to what got them there, which isn’t always the best option
BrendanC
$100 site donor 2024
Agreed, but I mentioned it in the tone that unless there is another problem to address, there is no need to change things up.
People are always coming on this site asking for advice on high mileage engines asking what oil to use ignoring what got them there in the first place. Unless they have an issue that further needs addressing, no need to change things around.
When switching oil, did you use the same viscosity? If the synthetic uses a lower W number, the cold viscosity will be thinner, which can magnify piston slap noise (for example).
What fully conventional oil were you using before? The synthetic you’re using now is a Group III base which is chemically similar if not identical to a “conventional”, whatever they means today. It’s just lower in contaminates and may have a higher viscosity index. But chemically the structure is the same, more or less. Not like the difference you’d see in a Group IV PAO.
Most startup noise issues are from the filter. The thickness at normal ambient is relatively insensitive to grade including the winter rating. The difference in viscosity with a 0W rated oil is only guaranteed below -35 or so. Above that there is no guarantee. An oil with a better winter rating may be thicker.
Most startup noise issues are from the filter. The thickness at normal ambient is relatively insensitive to grade including the winter rating. The difference in viscosity with a 0W rated oil is only guaranteed below -35 or so. Above that there is no guarantee. An oil with a better winter rating may be thicker.
The problem with that reasoning is that you can be heading towards a problem and think things are fine just because it hasn't showed up yet.
If there's a bridge out on the highway, but it's 30 miles ahead, does that mean your present course has no risk because there's been no risk so far and all the bridge thus far have been intact?
It's the difference between concluding a process worked because it's good vs it being good because it worked--so far.
Risk vs. Reward conundrum. Stay the course or try something new and possibly induce a problem?
I agree. Different engine oils can increase or mask mechanical noises. I've heard it myself. A few times a cold start rattling was instead due to a defective oil filter. I'd advise either returning to the earlier brand of oil or mitigate the noise with the volume control setting on the radio.
War of tribofilms is another possibility. No? At least for a while or some hundred miles?
Or maybe you used M1 and not Valvoline. J/K
In one of my cars, the very first change from dino & blend (Chevron Supreme 5/10W-30) to full synthetic was with PP 5W-30 and later M1 EP 10W-30. Both sounded super smooth!
Or maybe you used M1 and not Valvoline. J/K
In one of my cars, the very first change from dino & blend (Chevron Supreme 5/10W-30) to full synthetic was with PP 5W-30 and later M1 EP 10W-30. Both sounded super smooth!
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He only posts every 13 years, so we're going to have to wait until 2038 for the answers.
Did you change just the oil to synthetic? Same brand of oil filter as before? Cold start noise I tend to put more stock in an ADBV issue than the oil.
To expand on the ADBV issue, your cam phasers are hydraulic actuated by your oil. If your oil slow drains out of the engine, it can get a little rough on cold starts until it gets oil pressure up and the ECU sorts out the timing.
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That’s quite often how folks end up at the doctor as well… business as usual isn’t a good thing when the habits are bad…
