Could 10w-40 cause oil consumption in a 3.4 Tacoma?

[97_FZJ80]

When I got my 96 Tacoma with the 5VZ, the PO had put in Mobil One 10w40 high mileage, and at first it seemed to lose little to no oil. However, further and further into my 5k mile interval, it’s seemed to start losing more and more, to the point where I have to top it up every few days. I see a bit of seepage underneath but nothing major, which makes me think it must be internal.

Someone on the TacomaWorld forum said the heavier oil could’ve caused damage resulting in an increase in oil consumption: is there anything to this? I already bought another 6 quarts of the same stuff so I’m wondering if I should exchange it for some 5w-30.

 

[tblt44]

Thicker oil, loosing oil.
Don't think so.
You just got it so you haven't established a pattern.
Dump it and put the recommended weight in as a test for piece of mind

 

[atikovi]

it’s seemed to start losing more and more, to the point where I have to top it up every few days.

That's too vague. How many miles does it go on a quart of oil? How many miles on the truck? It would have to be smoking like a freight train if uses a quart every 100 miles or so.

 

[loneryder]

Why is this in the European oil section?

 

[71Chevyguy]

Will 10w40 CAUSE it to consume oil? No. But it is a Toyota and it will burn oil regardless even thought this was one of the known oil furnaces like many of their 4 cylinders.

I would switch to what is recommended and see how bad it is. Then you can check to see if going thicker helps slow it down at all. See how much it burns per 1,000 miles.

 

[97_FZJ80]

Why is this in the European oil section?

I saw import and assumed it was for foreign vehicles. Mods can move it, sorry for the mistake.

Will 10w40 CAUSE it to consume oil? No. But it is a Toyota and it will burn oil regardless even thought this was one of the known oil furnaces like many of their 4 cylinders.

I would switch to what is recommended and see how bad it is. Then you can check to see if going thicker helps slow it down at all. See how much it burns per 1,000 miles.

I thought the 3.4 was one of their better ones.

That's too vague. How many miles does it go on a quart of oil? How many miles on the truck? It would have to be smoking like a freight train if uses a quart every 100 miles or so.

It has 238k but I was told a “newer engine” was dropped in a few years ago, but they didn’t have proof. Compression is strong at around 185 PSI avg per cylinder. I’ve had to add about a quart in the last 1000 miles or so, but it seems like the pace of oil consumption has increased, leading me to wonder if the heavier oil lead to bearing wear or something.

 

[MParr]

Sounds like a tired engine to me.

 

[Leo99]

Some unscrupulous previous owners have been known to use certain additives that prevent short-term oil consumption. Don't know if that is the case here but it's a possibility.

 

[97_FZJ80]

Sounds like a tired engine to me.

Like I said, it has strong compression. I’m about to send in a sample to Blackstone for analysis however.

 

[atikovi]

I’ve had to add about a quart in the last 1000 miles or so, but it seems like the pace of oil consumption has increased, leading me to wonder if the heavier oil lead to bearing wear or something.

Heavier oil has nothing to do with bearing wear in this case. I'd be looking at valve stem oil seals if compression is good. Otherwise live with it. 1000 miles a quart on a 200k 27 year old engine isn't terrible. Certainly not worth taking the engine apart to fix.

 

[twX]

Apparently some engines will burn more oil when using a thicker grade, because the oil control rings can't handle the oil volume if the oil is too thick. Here's a video from Lake Speed Jr discussing this. The context of the video is modern cylinder coatings that help retain oil on the cylinder wall, which may not apply to your old Toyota, but if you've got clogged up oil control rings (a known issue with some Toyotas), it may be that they will work better with a thinner grade of oil, resulting in less blowby. The only way to know is to document your oil consumption with your current oil and then with a thinner grade.

 

[blufeb95]

Have you replaced the PCV valve?

 

[PontiacHO]

238k. One qt every 1k. About as good as you can be….

 

[SatinSilver]

Try some Valvoline Maxlife red bottle or some Castrol oil in it. Sometimes M1 and Pennzoil have a tendency for oil consumption when being switched over to it especially with older, high mile engines.

 

[kschachn]

It has 238k but I was told a “newer engine” was dropped in a few years ago, but they didn’t have proof. Compression is strong at around 185 PSI avg per cylinder. I’ve had to add about a quart in the last 1000 miles or so, but it seems like the pace of oil consumption has increased, leading me to wonder if the heavier oil lead to bearing wear or something.

Nope. Film thickness prevents wear, not causes it. You seem stuck on this, but that’s not how it works.

 

[kschachn]

Like I said, it has strong compression. I’m about to send in a sample to Blackstone for analysis however.

That’s not likely to show anything.

 

[97_FZJ80]

Have you replaced the PCV valve?

The PO said he replaced that along with the VCGs.

 

[97_FZJ80]

Try some Valvoline Maxlife red bottle or some Castrol oil in it. Sometimes M1 and Pennzoil have a tendency for oil consumption when being switched over to it especially with older, high mile engines.

I might try valvoline 10w30 high mileage and see how that goes. I'll pair it with the Mobil 1 filter.

 

[97_FZJ80]

Heavier oil has nothing to do with bearing wear in this case. I'd be looking at valve stem oil seals if compression is good. Otherwise live with it. 1000 miles a quart on a 200k 27 year old engine isn't terrible. Certainly not worth taking the engine apart to fix.

Valve stem seals are what I was thinking. Certainly not a cheap fix.

 

[madibob]

I've run 5w-40 in mine most of its life. Even a couple runs of 15w-40. Mostly 10k OCI. At 295k mine uses no oil.