f355spider
$50 Site Donor 2025
Ferrari almost exclusively uses 5W-40...the only exceptions are a few of the V12s in specific models and years where 10W-60 is recommended.
Up oil weight with high mile engines?
- Thread starter george1122
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Send off some used oil to one of the labs that do oil analysis. The analysis will tell you if you have excessive fuel dilution, which can be caused by a leaky fuel injector or too long oil change intervals.
Carlostrece
$100 Site Donor 2025
Some say to do that when engine is worn. Others say not do. Personally, I think it depends on the situation, but in specific situations I'm in favor of increasing the second number (after the w) by one grade. I like to leave the first number (before w) at stock number.
Increasing 2nd number increases viscosity at full op temp, which reduces oil leaking and oil. However, I think increasing op temp grade/viscosity should only be an option of last resort (if other easy cheap fixes have failed). Also, I personally would only increase by 1 grade, not more.
Others may have different opinions.
Thanks, I have done that. Unfortunately it is common to this engine.
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I don't think it's "misunderstood", it's just a colloquialism.
No. You can do it from mile 0. Your engine will be happy with a higher grade (not weight).
Did the lab test indicate the amount of fuel in the oil being acceptable? If not and there is nothing wrong with the fuel injection system, it shows oil change intervals need to be shorter.
Carlostrece
$100 Site Donor 2025
I've never heard anyone say that ^.
I think what you heard someone say is that viscosity increases (due to chemistry & physics) as oil temp goes down. i.e. - cold weather thickens an oil at cold start.
Any grade of oil will get thicker when colder. That does NOT mean you should choose a thicker grade of oil for cold weather. Just the opposite. You should choose an appropriately thinner grade of oil for extremely cold weather use to compensate for the cold trying to thicken it.
It's the first number (before the w) that you need to be smaller for colder weather startups. For example: 0wX instead of 5wX, or 5wX instead of 10wX.
They wouldn’t determine an acceptable level, at least not to me. Fuel in oil is bad on lots of levels.
It says old, not cold.
Carlostrece
$100 Site Donor 2025
It says old, not cold.
You're correct. I misread what he posted. I though he said "when engine is cold" but he said "when engine is old". I wish he'd say "worn" instead of "old" because it's the wear/condition/circumstances of the engine that matter, not the age.Now that I've read that correctly, I'll answer what he was really asking. It doesn't matter how old the engine is. What matters is the condition/wear/circumstances of the engine. If the engine is leaking or burning oil, or having fuel dilution, that is when many say to increase the oil viscosity. Specifically to increase the 2nd # after the w by 1 grade.
For example: My car is older than my 2 neighbors' cars, but my car engine is in much better condition than their cars.
My car is in good condition (no oil leaking, no oil burning, no fuel dilution). So I continue using stock viscosity oil for it, which is 5w30.
One neighbor's 03 Honda CR-V 2.4L loses 5w20 oil rapidly. I still haven't conclusively diagnosed it, but stuck rings and oil burning are likely causes. Diagnoses is ongoing. Along with a few other fixes, I will also change it's oil from 5w20 regular oil to 5w30 VRP for 4 OCI. Then change to Quaker State Ulimate Protection Full Syn (QSUPFS) 5w30 (which has higher KV100 cSt op temp viscosity than other 5w30 full syn USA oils). Also, she drives exclusively city miles. So I will decrease OCI from ? to 3.5K miles, which will be about 2 years for her.
My other neighbor's 11 Hyundai Elantra 1.8L has been having a severe fuel dilution problem (watery thin, black, stinky used oil). She was using a 5K OCI and 5w20 regular oil. I will switch it to 5w30 VRP for 1 OCI. Then 5w30 QSUPFS after that. She drives exclusively city miles. So I'll decrease her OCI from 5K to 3.5K, which will be about 2 years for her.
I had a worn out push lawn mower than burned 30 grade oil like crazy (far worse than my neighbor's CR-V). So I changed the lawnmower oil to 40 grade. Then much less blue smoke and much less oil consumption. It worked well using 40 grade for many more years with no problems. The mower frame finally broke. So the engine outlasted the frame, but only because increasing oil grade from 30 to 40 gave the engine more years of good service life.
The amount of gas in oil is measured by the labs as a standard procedure, IIRC. If the amount of gas in oil is above a certain amount, the vehicle owner should shorten the OCIs or find out why there is too much gas in oil.
In retrospect, I should have used the term worn.
Now that I've read that correctly, I'll answer what he was really asking. It doesn't matter how old the engine is. What matters is the condition/wear/circumstances of the engine. If the engine is leaking or burning oil, or having fuel dilution, that is when many say to increase the oil viscosity. Specifically to increase the 2nd # after the w by 1 grade.
For example: My car is older than my 2 neighbors' cars, but my car engine is in much better condition than their cars.
My car is in good condition (no oil leaking, no oil burning, no fuel dilution). So I continue using stock viscosity oil for it, which is 5w30...
If too much fuel is in the oil, shouldn't the OCIs be shortened? The labs that analyze used oil determine how much fuel is in the oil. Wouldn't that be a good idea to do for the neighbors you mention?
Exactly. It blows people mind when some one asks "would mixing as 20 and a 30 make a "25"?" for example. Technically incorrect but I easily understand what they mean.
I'd run and it is what I ran in my '05 Element's K24, which was QSFS, M1, and Castrol Euro 0/5w-40. No issues at all for many thousands of miles and noticed zero difference in mpgs either.
You could also try a fuel treatment, Gumout Multisystem Tune Up, and Berryman's B12 Chemtool are my favorites, or a TCW3 2 stroke oil, 1oz/5gal, to sometimes help with noise under the hood coming from the injectors. I use the fuel treatment 2xs per year and then run the 2 stroke throughout the year and that has helped keep the injectors quieter on several of my vehicles. You may give that a shot if the oil doesn't make too much of a difference.
Carlostrece
$100 Site Donor 2025
Yes. I previously said I'm shortening her OCI from 5K to 3.5K and increasing viscosity from 5w20 to 5w30. It's a 1, 2 punch combination solution.
The underlying cause of her fuel dilution is that all her driving is short trip city driving. I can't change her driving situation, but I can use 5w30 and change oil more often.
Another thing that would help would be using Top Tier fuel (such as Shell, Chevron, Sinclair, U76, etc) but she refuses to do that. I can lead a horse to water, but I can't make it drink. We have a U76 gas station ½ block from home, but she drives 10 blocks to get Safeway gas.
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Carlostrece
$100 Site Donor 2025
What would mixing 20 & 30 make, if not 25? IIRC some BITOG members have posted that they mix 2 viscosities to get a viscosity in between. No one objected when they said it.
Patman
Staff member
But there is no such thing as a 25 grade. Mixing those two viscosities will just result in the final viscosity possibly being somewhere between 8.5-10.5 cst at 100c, so somewhere between the top end of the 20 grade range to the bottom end of the 30 grade range. And mixing different oils is no guarantee that they will work together like people think. Playing “backyard chemist” doesn’t make a better oil than the oil manufacturers can do. Just find an oil that has the exact same viscosity that you desire in the first place instead of trying to create your own.
I do shorten the OCI by half. I also use a higher HT/HS oil as well.
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