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I've got a 2006 oil burning RAV. It's got a hundred eighty thousand miles on it. At 85k the Piston thing was done and it came back about a year ago to my dissatisfaction.

The dealer said they'll use 5w 20 regular oil going forward to save me a few bucks. They said it doesn't matter if every thousand miles or so I dump in a quart of synthetic or regular... it's inconsequential.... But to make sure I ask the quart.

So about every 6 weeks or so I'm adding a quart of oil. I get the oil changed about every three to 4 months....or around 5k.

I was due for some oil and was in Costco. They did not have the mobil I usually buy on sale but they had Kirkland brand which seem to get good reviews so I picked up 10 quarts In two 5 quart containers. When I got home I realized I had purchased 5w 30 synthetic instead of 5w 20.

When I top it off with a quart every six weeks or so is there any consequence to using the 5 w 30 to top it off? I have absolutely no problem returning the 5w 30 and getting the 5w20.... I just want to understand what the consequence of putting the 5w 30 in every thousand miles.

So I get an oil change with 5w 20. By the time my next oil change rolls around I would have probably added 2 - 3 quarts a 5w 30 in...is there any harm? Is it going to cause me to start burning oil at a higher rate?
 

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To clarify... I looked through my records....the local place that serviced the rav from 2006 through recently appears to always have used 5w 20 oil. They got bought out and we almost immediately had issues with the new owners and switched to Toyota.

My first oil change with Toyota before we knew the excessive consumption had returned...they used 0w 20. I think that may have been when they said to increase the weight to 5w 20. At least the next two oil changes used 5w 20 according to my receipts. On my last oil change at Toyota I see they use 5 w 30! So now I'm confused.

I'm going to be due for an oil change and I'm wondering if 5w 30 is the best way to go and I'll keep the oil I just bought? I want to do what's best because we might not be returning to that Toyota dealership in favor of another locally recommended person.
 

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If you are burning oil at a fast rate would it not be better to use a thicker grade such as 10W30 conventional oil? This grade is thicker so it will slow the oil burning and reduce cost. Synthetic oil is great for extended oil change intervals but why pay a premium if it is not even going to last very long?
 

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So that is what I am asking. It looks like a dealer went from 0 w2 to 5w 20 and last time 5w 30... I don't know if they are doing this on purpose or on a whim... I have no idea. What should I be using.... They told me synthetic vs. Regular won't make a difference in so far as how fast it burns through the oil ...it will make a difference in so far as how much it costs. However I picked up oil up today at Costco... it happened to be synthetic and it was cheaper.

I'm going to be getting an oil change. Should I tell them to use 5 w 30 regular and can I top it off with this synthetic?

is there a downside to this? Or am I just overthinking this whole thing...
 

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So that is what I am asking. It looks like a dealer went from 0 w2 to 5w 20 and last time 5w 30... I don't know if they are doing this on purpose or on a whim... I have no idea. What should I be using.... They told me synthetic vs. Regular won't make a difference in so far as how fast it burns through the oil ...it will make a difference in so far as how much it costs. However I picked up oil up today at Costco... it happened to be synthetic and it was cheaper.



I'm going to be getting an oil change. Should I tell them to use 5 w 30 regular and can I top it off with this synthetic?

is there a downside to this? Or am I just overthinking this whole thing...
There was a member who had a oil burner. When he switched to 10W-30 oil consumption dropped to half.
 

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Discussion Starter #6
I just don't want to make it worse.

She's at an age where things obviously will start to need to be replaced. I've done the water pump struts even the rims... the Piston thing coming back after I had it fixed once already really gets me upset. I wrote a letter to Toyota and they basically told me to go pound salt.
That's one of the reasons why were
into Subarus now .. we'll see if we have any better luck with them. Nevertheless I was hoping this RAV would get my daughter through college without major investment.
 

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EVERY high mileage engine will eventually need a bump in oil thickens (compared with factory brand new engine), to compensate for the wear. I would say go with 5W30 synthetic immediately.
If you want to use standard oil that would be 10W30, but be aware that that cannot be "added" between oil changes as much as the synthetic oils, or you will get carbon deposits inside the engine.

PS: 4 cylinder engines will always have more wear on their cylinder rings, versus the 6 cyl variants, no matter what manufacturer tells you. On 4 circles versus 6 circles, comparative area, it's just less circumferince to seal. So the seal material gets exposed to a higher pressure load per same length of that seal.
 

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Yes you're overthinking it! Use the least expensive oil you can find. 5W-20, 5W-30, 10W-30 synthetic or regular, mix or match no matter, just make sure it doesn't get low. If it was mine I'd use 10W-30 and NOT do oil changes since you're continually changing it anyway. Just change the filter every 5K.
 
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Dr. Dyno, just adding normal oil, especially without oil changes, is a bad idea. It will make sludge deposits. Synthetic oils have better detergent proprieties and can be added longer, however oil changes are needed too, including the filters. A filled-up filter will open it's by-pass and leave all the particulates circulate.


 

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I prefaced my "not change" comment with "if it was mine" and I'll stick by it.
 

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Sludge comes from not changing oil over long periods of time and miles. The oil uses up its detergents/additives because it stays in the engine. That's not the case here. Burning oil is the equivalent of draining old oil and adding a new a quart at a time so the detergents/additives are continually being refreshed. If you remove a quart every 1000 miles and add another quart, however you do that, you've done an oil change every 4000 miles.
In point of fact the oil actually stays fresher overall than a "normal" 5000 mile oil change.
 
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Discussion Starter #13
Yes the major reason for getting the car in roughly every 4 to 5 months or 5000 miles is to get the filter changed. It always kind of irked when it's due for an oil change a couple weeks after I just added a new quart. And in those cases I usually wait till it's almost down another quart.

So I'm going to go with 5w 30 because I suspect the dealer has already bumped it from 0 to 5w 20 to 5w30... I don't know that they want me to use the 10 weight. Plus I have a bunch of 5 w 30 weight synthetic oil at home.

whether it's been 0...5w20 or 5w 30 it's still going through a quart every thousand miles....

so whatever piston part thing they fixed years ago at 80,000 miles they probably through the same crap parts in there it'll be interesting to see if a bunch of owners don't start complaining that they're having to problems all over again.
 

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Using the Costco 5W30 synth will be just fine, no worries. That brand of synth is a decent oil and the price is so reasonable that it may even be cheaper than some non synth oils.
 

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I don't know that they want me to use the 10 weight.
In the case of non-synthetic oils, the cold viscosity is given by the base oil. So a 5W oil will start thinner than the 10W. The hot viscosity will have to be adjusted via additive packs, so the 5W30 will have more additives than the 10W30. In an engine that burns oil, those additives will wear faster because increased amount of exhaust gases in the crankcase will affect the oil (acidity).
Synthetic oil require very little additives.

In point of fact the oil actually stays fresher overall than a "normal" 5000 mile oil change.
An engine that "burns" oil most likely has a lot of exhaust gases above crankcase. I saw cars that would block the PCV valve with oil, then proceed to blow up the dip stick under the pressure. A test that I do on cars is to remove the oil filler cap and see if there are gases exhausting through there. At some point even unburned fuel vapors can pass by worn pistons (there are plenty of regimens that a modern engine runs rich, especially when cold).
All those gases will affect the oil. You think you have "fresh" oil when in fact you have oil with maybe only 1/4 of the additive pack left intact.
 

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Discussion Starter #16
Ok... Not really following... As far as I know the car has the Piston issue for the second time if that helps
 

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I have never heard of carbon deposits when mixing synthetic and regular oil. If this was the case semi-synthetic oil that are sold would do the same thing.
 

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I didn't say that. Just that adding continuously normal oil, without any kind of oil changes, might create deposits.
 
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