Should I extend my oil change intervals?

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I have a 01 Corolla with 285k miles, I have always used an API SL 20w50 Conventional oil and a 3k mile interval. When I began to browse through this forum I decided to start using an API CI4/SL rated 15w40 oil because I learned that a thicker oil isn't always the best option.

My car is using 1 qt of oil every 1k miles and it has a 4qt oil pan, so at the end of the interval I have added more than 3qts of make-up oil. I'm only getting 25 mpg because of the way I drive. My guess with this level of oil consumption and this fuel mileage is that I shouldn't extend my OCI too much, but I don't know if even in this "harsh" conditions a 3k OCI is an overkill. My next oil change will be with Motorcraft HDEO 15w40 CJ4 Rated BTW.
 
when did it start consuming that much oil? If its been gradual over time it may br the rings are caked up. I high mileage oil or cleaning oil additive may help slowly desolve it,

Using that much oil you could probably leave the filter on for 6k since you have already changed most of the oil.

How does the oil look on the dipstick at 3k with that much fresh oil added?
 
You may want to switch to a high mileage synthetic oil and extend the OCI to 5000-7500 miles. Do you know what's causing the oil loss? leaks? oil burning?
 
SL rated? Is that really common oil in your country or old stock?

But yea I would go for 4-5k as long as you keep it topped off and use a newer rated oil. The Motorcraft HDEO 15w40 CJ4 will be fine. Try and see if you can find some Valvoline Maxlife 15w40.
 
I would extend the oil change interval to maybe 6,000 miles or more. No need for synthetic in my opinion. If you cut open the oil filter and find carbon in the media pleats, burnt fuel is blowing past the rings and this will lead to carbon fouling the rings. Maybe this has already happened of the rings are simply worn.
 
You could run 10k with a fram ultra as long as you keep up with the top offs. Your car is basically changing its own oil. I would check all the usual suspects though.

PCV valve
Leaky gaskets
Some sort of engine flush to free up stuck rings. Kreen or BG109.

My personal favorite HM oil is M1 HM 10w-30. Its almost thick enough to be a 40 and has great cleaning cleaning power
 
If you burn through almost all of your oil during a normal OCI what is the point of even worrying about changing it out. Using 1qt every 1000 miles, I wouldnt even bother changing the oil, just keep topping it off and only change the filter everything now and then. The add pack will constantly be refresh by the sheer quantity of oil being consumed.
 
Sounds like a typical 1ZZ-FE. Here in the US, Toyota specs a 5w30 for that engine. I would use a high mileage 5w30 at 5k intervals. If you only have 15w40, thats lighter than the 20w50 you have been running. I averaged 35 MPG and had a few 37's on my previous 2001 Corolla with the 5w30. Most of these engine burn some oil just FYI.
 
Originally Posted By: danez_yoda
when did it start consuming that much oil? If its been gradual over time it may br the rings are caked up.
The consumption increased gradually over its life. It went up from 0.8 qts to 1 qt every 1000 miles because I went from 20w50 to 15w40.

The user manual says you can use 20w50 in the temps that my engine sees, the coldest starting temp is 68 F, there are plenty of 300k miles plus engines that have used 20w50 without engine rebuild down here in Venezuela


Originally Posted By: danez_yoda
How does the oil look on the dipstick at 3k with that much fresh oil added?
It doesn[t looks black, but it does look dark brown, but I have learned in this forum that dark oil can have more usable life in it, the only way to know is with an UOA, but I cant do one, it is so expensive down here.
 
Originally Posted By: anndel
You may want to switch to a high mileage synthetic oil and extend the OCI to 5000-7500 miles. Do you know what's causing the oil loss? leaks? oil burning?
Not any leaks, it might be burning, but it the smoke isnt visible
 
Originally Posted By: Emanuel
I have a 01 Corolla with 285k miles, I have always used an API SL 20w50 Conventional oil and a 3k mile interval. When I began to browse through this forum I decided to start using an API CI4/SL rated 15w40 oil because I learned that a thicker oil isn't always the best option.

My car is using 1 qt of oil every 1k miles and it has a 4qt oil pan, so at the end of the interval I have added more than 3qts of make-up oil. I'm only getting 25 mpg because of the way I drive. My guess with this level of oil consumption and this fuel mileage is that I shouldn't extend my OCI too much, but I don't know if even in this "harsh" conditions a 3k OCI is an overkill. My next oil change will be with Motorcraft HDEO 15w40 CJ4 Rated BTW.

My son owns a 96 Corolla with 260K miles on the 1.8 engine.
About a year and a half ago my friend changed the wp, by pass hose, upper & lower hoses, crank seal, timing belt with all of the timing components, valve cover gasket & plug tube gaskets, PCV valve, all of the drive belts, and cleaned the throttle body, all for $150 labor. My son bought all of the parts online from PEP BOYS and ROCK AUTO for $380.
Before any of this was done the engine was leaking and burning almost 2 qts. of oil in 1500 miles. It was getting like 22-23 mpg highway. Afterwards it went up to the usual 32-35 mpg. Prior to all the work we changed the plugs, wires, cap & rotor, trans. fluid and filter. We also did a 4 day piston soak with a mixture of MMO & SEAFOAM. He used HM 10W40 oil prior to all of the work and now uses HM 5W30. I bet if you did some of the similar things to your engine it might help! GOOD LUCK!
 
Originally Posted By: Jimzz
SL rated? Is that really common oil in your country or old stock?
The more common oils are Conventional API Sl rated and Synth Blend SM Rated, there is a 5w40 SN Rated but I am scared to use it because it isnt high mileage oil and because I have seen an increse with oil consumption going from 20w50 to 15w40, so I think that with 5w40 it is going to be worst.

Could I be wrong? Can 5w40 Group 3 Synth SN rated lower my consumption if 15w40 increased it coming from a 20w50?
 
If it't using that much oil I would just keep topping off and not change the oil. Just change the filter every 10,000km or so. I had a 1986 Dodge Caravan that had a Mitsubishi engine that would burn the same amount of oil due to bad valve seals and that is what I did with it. Worked fine.
 
Last edited:
Originally Posted By: WobblyElvis
I would extend the oil change interval to maybe 6,000 miles or more. No need for synthetic in my opinion. If you cut open the oil filter and find carbon in the media pleats, burnt fuel is blowing past the rings and this will lead to carbon fouling the rings. Maybe this has already happened of the rings are simply worn.


Great idea! I am going to cut open the current oil filter to look for carbon in the media pleats.

The engine was overhauled with new piston, rings, gasket, seals and bearings 35k miles ago but the cylinders werent chechek in a machine shop, they might be out of round and thats whats causing the oil consumption.

I want help to decide an reasonable OCI in this conditions using whats avaible here: Conventional API SL oil or API SN Synthetic Oil.
 
Originally Posted By: Lasthope05
If you burn through almost all of your oil during a normal OCI what is the point of even worrying about changing it out. Using 1qt every 1000 miles, I wouldnt even bother changing the oil, just keep topping it off and only change the filter everything now and then. The add pack will constantly be refresh by the sheer quantity of oil being consumed.
But my fear is that the engine must have definitely blowby and this is making combustion by products get into the crankcase causing oil oxidation and sludge in the worst cause.

I dont know if I am being to paranoic and I should simply extend intervals, but I really want to get 200k miles more from this engine if its possible, I want to take the best care of it but I dont want overkill OCI neither.
 
Originally Posted By: sw99
Sounds like a typical 1ZZ-FE. Here in the US, Toyota specs a 5w30 for that engine. I would use a high mileage 5w30 at 5k intervals. If you only have 15w40, thats lighter than the 20w50 you have been running. I averaged 35 MPG and had a few 37's on my previous 2001 Corolla with the 5w30. Most of these engine burn some oil just FYI.
I am gonna stop saying I have a 01 Corolla in this forum
grin.gif
, here in Venezuela the Corolla came with the 7AFE engine until the 2002 Model, this engine is also known for oil burning, not so much like the 1ZZFE but my oil consumption is considered normal for the mileage that it has and the way I drive it (to get 24 mpg in a Corolla you have to drive it hard, I dont drive it too hard, but I dont drive it slowly neither).

Do you think that a 5k mile interval would be safe on a old API SL oil and this driving conditions?
 
You could also have someone pull the bottom end apart and put in revised rings/pistons that don't burn oil. The oil savings alone over the next 200,000 miles you want will be worth it.
wink.gif


This can be done without removing the engine from the vehicle if it's done on a vehicle hoist.
 
Originally Posted By: BlueOvalFitter
Originally Posted By: Emanuel
I have a 01 Corolla with 285k miles, I have always used an API SL 20w50 Conventional oil and a 3k mile interval. When I began to browse through this forum I decided to start using an API CI4/SL rated 15w40 oil because I learned that a thicker oil isn't always the best option.

My car is using 1 qt of oil every 1k miles and it has a 4qt oil pan, so at the end of the interval I have added more than 3qts of make-up oil. I'm only getting 25 mpg because of the way I drive. My guess with this level of oil consumption and this fuel mileage is that I shouldn't extend my OCI too much, but I don't know if even in this "harsh" conditions a 3k OCI is an overkill. My next oil change will be with Motorcraft HDEO 15w40 CJ4 Rated BTW.

My son owns a 96 Corolla with 260K miles on the 1.8 engine.
About a year and a half ago my friend changed the wp, by pass hose, upper & lower hoses, crank seal, timing belt with all of the timing components, valve cover gasket & plug tube gaskets, PCV valve, all of the drive belts, and cleaned the throttle body, all for $150 labor. My son bought all of the parts online from PEP BOYS and ROCK AUTO for $380.
Before any of this was done the engine was leaking and burning almost 2 qts. of oil in 1500 miles. It was getting like 22-23 mpg highway. Afterwards it went up to the usual 32-35 mpg. Prior to all the work we changed the plugs, wires, cap & rotor, trans. fluid and filter. We also did a 4 day piston soak with a mixture of MMO & SEAFOAM. He used HM 10W40 oil prior to all of the work and now uses HM 5W30. I bet if you did some of the similar things to your engine it might help! GOOD LUCK!


The engine was overhauled with new pistons, rings, seals and gaskets 35k miles ago. It hasnt any leaks but it did overheated 12k miles ago, it was consuming oil before the overheat like 1.5 qts between 3k OCI but now after the overheat the consumption increased to 2.5 qts every 3k miles (and even more now with the 15w40 instead of the 20w50).

Do you think that 35k miles old rings could be cooked up?
 
Originally Posted By: StevieC
You could also have someone pull the bottom end apart and put in revised rings/pistons that don't burn oil. The oil savings alone over the next 200,000 miles you want will be worth it.
wink.gif


This can be done without removing the engine from the vehicle if it's done on a vehicle hoist.
That is true, but I wouldnt open the engine a 2nd time without boring the cylinders in a machine shop.

What OCI interval would you use if you treated this car like you loved it?
 
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