Synthetic or Dino HDEO in my 285k car?

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I have a 01 Corolla (with an 7AFE engine not the 1ZZFE) with 285k miles. It´s burning 1 qt of oil every 1300 miles which is acceptable for me. I can get a Synthetic 5w40 Oil almost at the same price of the Dino HDEO 15w40 oil that I´m currently using, the HDEO is API SL rated and I can get two main synthetics with the following ratings:

- PDV 5w40: API SM, ACEA A3/B3 04, MB 229.3, VW502/505, BMW Longlife Oil 01
- Venoco 5w40 & 10w30: API SN


My questions are:

Would I see any benefits using the Synthetic 5w40? My coldest starting ambient temp is 68 °F, so the 15w40 isn´t that thick at that temp.
Would the 5w40 increase the oil consumption? My guess is that the 5w40 would have a lower NOACK than the HDEO 15w40, I think the oil burning is being caused by the rings, valve seals are almost new and there aren´t any leaks. I don´t know how NOACK would affect oil consumption in this condition.
Would the 5w40 Synthetic harm my engine for being so thin? My car used Dino 20w50 98% of its life, this will be the first time in something that thin.
 
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With the amount of oil you're burning synthetic will be expensive. You also have a lot of miles so synthetic could clean some gunk away from the gaskets and cause leaks where there were none before. (Gunk acting like a seal.)

I would run a high milege oil like Valvoline Maxlife in that engine.

68F is nothing for conventional oil.

BTW: Had a great time in Margarita Island back in 1999 when I was there... Before things took a turn.
frown.gif
 
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Originally Posted By: StevieC
With the amount of oil you're burning synthetic will be expensive.
Why it will be expensive? Would it increase oil consumption? I can buy the Synthetic at the same price if I find offers.

Originally Posted By: StevieC
You also have a lot of miles so synthetic could clean some gunk away from the gaskets and cause leaks where there were none before. (Gunk acting like a seal.)
Seals are 35k miles old so I´m not worried about that.
 
If the seals are new (35K miles) then go for synthetic at the same price as conventional.

Better protection, better cleaning, better flow when cold although it doesn't really get "Cold" there.
smile.gif
 
Originally Posted By: StevieC
BTW: Had a great time in Margarita Island back in 1999 when I was there... Before things took a turn.
frown.gif

LOL, Margarita is great, I went 2 years ago
 
Honestly, whatevers a decent name thats on sale Id run in that situation, but a high mileage oil may help slow the consumption down. With the amount youre burning, its constantly getting refreshed, so longer oil change intervals would work too.
 
I'd just use the 5w40 synthetic and keep topping it off. There isn't any magic elixir of an oil that's going to stop oil consumption. I'd also stretch the oil change interval out to at LEAST 10k miles.
 
Originally Posted By: Emanuel
Would the 5w40 Synthetic harm my engine for being so thin? My car used Dino 20w50 98% of its life, this will be the first time in something that thin.


So, 5W-40 is a thin oil in Venezuela? Interesting.
 
Originally Posted By: Nick1994
I'd just use the 5w40 synthetic and keep topping it off. There isn't any magic elixir of an oil that's going to stop oil consumption. I'd also stretch the oil change interval out to at LEAST 10k miles.
Would yo do 10k OCI with high sulphur fuel (600 ppm) and no thermostat? I do 3k OCI for that reasons
 
Originally Posted By: Merkava_4
Originally Posted By: Emanuel
Would the 5w40 Synthetic harm my engine for being so thin? My car used Dino 20w50 98% of its life, this will be the first time in something that thin.


So, 5W-40 is a thin oil in Venezuela? Interesting.
People doesn´t know anything about oil, they think 20w50 reduces wear and I used to think so, but I have learned that thicker oil means less oil flow. I´m using 15w40 because is readily avaible (because people use it in new engines) and is considerable thinner at cold starts.
 
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Originally Posted By: Emanuel
People doesn´t know anything about oil, they think 20w50 reduces wear and I used to think so, but I have learned that thicker oil means less oil flow. I´m using 15w40 because is readily avaible (because people use it in new engines) and is considerable thinner at cold starts.

They will all flow the same as long as they can be pumped, and in your climate the cold-weather specification (W) won't make any difference at all. At your ambients the two grades are going to have very similar viscosity.
 
Originally Posted By: kschachn
They will all flow the same as long as they can be pumped

I don´t know if my guess is right, but wouldn´t a more thicker oil increase oil pressure? And extra oil pressure wouldn´t go to the relief valve of the oil pump, reducing oil flow?

Originally Posted By: kschachn
And in your climate the cold-weather specification (W) won't make any difference at all. At your ambients the two grades are going to have very similar viscosity.
graph_4_viscosity_comparison.jpg

According to this image a 15w40 has a 42% lower KV at 20 °C (68°F which my coldest temp). And PDS says that at 40 °C the KV of the 15w40 is 35% lower. That looks noticable for me.

What is funny to me is how USA people thinks that a 20w50 is a thick oil and according to that data in the image the viscosity of an 5w30 at 0°C-32°F is the same that the one from a 20w50 at 20°C-68°F that is our coldest starting temp. BTW is there a way to extrapolate KV of an oil knowing it viscosity at 40°C and 100°C and using the VI?
 
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Originally Posted By: Emanuel
People doesn´t know anything about oil, they think 20w50 reduces wear and I used to think so, but I have learned that thicker oil means less oil flow. I´m using 15w40 because is readily avaible (because people use it in new engines) and is considerable thinner at cold starts.


If that was the case then me running 5w20 would show all sorts of wear metals on my UOA's and I'm showing almost all 0's!
 
Originally Posted By: StevieC
Originally Posted By: Emanuel
People doesn´t know anything about oil, they think 20w50 reduces wear and I used to think so, but I have learned that thicker oil means less oil flow. I´m using 15w40 because is readily avaible (because people use it in new engines) and is considerable thinner at cold starts.


If that was the case then me running 5w20 would show all sorts of wear metals on my UOA's and I'm showing almost all 0's!
I´m pretty sure I could use a 5w30 in this engine but there is no sense in using something that is not easy to find
 
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