Oil consumption in reman engine

toyota

#1

Hi all, my 1993 pickup has a recently installed remanufactured engine. The engine is from ATK and I trust it to be without defect. My mechanic however, I am a little bit worried about. After 3000 miles on the new engine, there is a tiny bit of oil consumption. He told me to expect zero oil consumption after the break-in period, after which he changed out the break-in oil. Should I be worried about this oil consumption?


#2

How much is a tiny bit? If you can tell us in quarts per 1000 miles or quarts per month, we might have an idea. “A tiny bit” isn’t descriptive enough.


#3

Say half a quart in 2800 miles


#4

How many miles are on this reman engine now? How much oil is a tiny bit? And how many miles since the oil change? What brand and weight of oil was used for the last oil change?


#5

The reman engine has 3500 miles on it. Drove it for 500 miles as a break in with a lower viscosity oil, now it’s got heavy oil, 20w50. Since the break-in oil was changed out, I’ve hit 2800 miles with about a half quart consumption.


#6

Define “tiny bit”. A quart every 5,000 miles? A quart every 1,000 miles? A quart every 10,000 miles? How much?

A small amount of consumption is nothing to be concerned about. A properly rebuilt engine will have “honing” on the cylinder walls. These are controlled crossed scratches. Their primary purpose is to entrap a small amount of oil after the oil rings (I refer to them as “wiper rings”) wipe the excess away, to provide lubrication for the pistons and piston rings to slide by. Without that thin film of oil, the engine would self-destruct. That miniscule film of oil gets disposed of by the combustion process as the piston moves down the cylinder pushed by the combustion gas expansion from whence comes the power.

I believe that “zero oil consumption” is a misnomer. I hear it often, but believe it to be a misleading misrepresentation. The only question I have is “how much oil is it using?”.


#7

I see. That sets my mind at ease. Thanks- this is a wonderful forum for an owner of an old car!


#8

You’ve got the wrong oil in the engine.

The engine takes 5W-30 oil.

With the 20W-50 oil in the engine, the engine is being worn out at each cold start.

It’s no wonder that the engine is starting to burn oil.

Tester


#9

Get that 20W50 out of there and replace it with a quality 5W30 oil. Unless you live on the equator that oil is too thick for that reman engine and is causing excessive wear every morning. Over the long term that 20W50 can actually cause oil consumption issues.


#10

Really? I’m in southern California. Do people agree that a thinner oil would be better? This was my mechanics choice…


#11

Then they’re no mechanic.

The oil is 20W oil under ambient temperatures down to zero degrees. So each time the engine is started cold it’s being starved of oil for a short period time. Which wears out the piston rings.

With a 5W oil it’s thinner, so it flows faster to moving engine parts protecting them during cold starts.

Tester


#12

That is excellent consumption.
I’d be inclined to use 10W30 in southern Cal, but talk with the engine rebuilder about it. he’s the one that’s backing your warranty. He should be able to advise you. I do know that last September when I was visiting my son it got well over 100F in the Valley… beautiful over the mountains on the PCH however. There must have been a 35F difference!


#13

I suggest you don’t take any advice from your mechanic, in regards to engine oil viscosity

I have no clue where he got the idea that 20W50 is appropriate for your engine, but he’s dead wrong

Perhaps he’s used to working exclusively on large and older diesel engines. If that’s the case, maybe he should stick to that, because 20W50 has no business being in YOUR crankcase


#14

I agree, change that oil ASAP. I would use either 5w30 or 10w30, on a 93, I’d be more inclined toward the 10w30, but thats me.


#15

Just my 2 cents and which may be at odds with other opinions.

I don’t feel that a half quart in 2800 miles is acceptable. What’s it going to be going through by the time the engine has 50k miles on it?

As for 20/50 motor oil I don’t consider that the kiss of death for an engine; even an old tired one. In the past when I had 2 Subarus with high miles and my Sable with very high miles I ran 20/50 in all of them with no issues at some point in their lives.
I sold the Sable with well over 400k miles on it and I used 20/50 for about the last 200k miles before unloading the car.

Of course I live in OK where it gets pretty hot and most of my driving is not short distance driving either.

I wonder if there is an issue with the reman engine. I’m not familiar with ATK but I have seen a number of reman engines with horrible problems from the get-go.
Probably the worst example was a Chevy 350 I installed into a pickup for someone. It was going through a quart per 5-10 miles and after a 100 miles the engine came out and went back to the reman facility.
Apparently the builder was a disgruntled employee on the way out the door. All 8 pistons were installed sans the oil control rings… ;-(

A reman facility in Tulsa sent out 75 VW air cooled engines. Seventy of them came back blown up or just short of being blown up; including the one I installed in a Westfalia bus.


#16

very interesting. well i don’t know what to do. i guess talk to another mechanic? but even assuming that the 20W50 is the wrong oil, it couldn’t very well account for the oil consumption, could it? after a mere 3000 miles? ATK warranty covers the engine for unlimited miles for 3 years. i am inclined to trust the motor itself.


#17

“but even assuming that the 20W50 is the wrong oil”

It’s not just assumption

It’s fact

It IS the wrong oil viscosity


#18

point taken. but does it then account for oil consumption?


#19

i’ll check with ATK and report back tomorrow


#20

Oil viscosity can account for increased oil consumption, but not a higher viscosity oil. Auto manufacturers have started telling customers to expect increased oil consumption with 0W20 oils that are popular in new cars. Higher viscosity oils, like your 20W50, are sometimes used in the hope that leakage past the rings might be less, for instance. The high viscosity oil isn’t causing increased oil consumption.