04 Tacoma 240K - High varnish, some sludge was running T6 10-15K

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Like others say, your OCI is too long. The varnish is indicative of this - you're getting oxidation of the base oil, additive(s), or both.

In my experience, Rotella's are set up for diesel OCI's. I think they're up to 15,000 miles, but they have 12 gallon sumps. Your Tacoma V6 is what - 1.5 gallons? Rotella is heavy with DDI for soot suspension as well, that you don't need for your small gasoline engine. If you're running a mixed fleet, sure, but then just tone down the OCI. Way down.

I'm using PUP in my gasoline engines. Haven't opened one up yet.
 
That doesn't look bad to me. Any engine is going to varnish / darken, moreso with extended drains. That amount of varnish / coloring is pretty typical for most any high mileage engine I've taken apart, even ones that have had 3-5k changes religiously. I'd keep doing what's been working, though I do think 15k is excessive in the absence of regular UOAs. I'd be more comfortable with a 10k interval assuming mostly highway mileage, and a UOA performed every now and again, say every 2-3 changes.
 
Originally Posted by aquariuscsm
Originally Posted by CT8
I don't see sludge.


Me either. It actually looks really good! No wear at all on the camshaft lobes.



+3....

Looks rather good...
 
Originally Posted by The Critic
T6 really isn't designed for extended drains, especially not in gasoline engine. I would have stuck with the max Toyota drain interval of 7500 miles.

If you insist on 10-15k service intervals I would consider Mobil 1 Extended Performance or Amsoil Signature Series.

Best answer. Use a PCMO and 5-7.5k OCI.
 
Originally Posted by The Critic
T6 really isn't designed for extended drains, especially not in gasoline engine. I would have stuck with the max Toyota drain interval of 7500 miles.

If you insist on 10-15k service intervals I would consider Mobil 1 Extended Performance or Amsoil Signature Series.


+1

Much better choices for long life....
 
Originally Posted by LubricatusObsess
Like others say, your OCI is too long. The varnish is indicative of this - you're getting oxidation of the base oil, additive(s), or both.

In my experience, Rotella's are set up for diesel OCI's. I think they're up to 15,000 miles, but they have 12 gallon sumps. Your Tacoma V6 is what - 1.5 gallons? Rotella is heavy with DDI for soot suspension as well, that you don't need for your small gasoline engine. If you're running a mixed fleet, sure, but then just tone down the OCI. Way down.

I'm using PUP in my gasoline engines. Haven't opened one up yet.


Agree.

The 15k OCI on our 2000ISC was 15k, although as a medium duty engine it's sump was only 6.5 Gals. That OCI was also contingent on a filter that had a built in bypass filter to reduce fines in the oil.

Providing a real world test of why the original OCI is correct should be useful.
 
You've gotten a lot of good advice here, of which I agree. The inside of this engine looks great for that kind of mileage. Someone said that the wheels will fall off the truck before you have engine problems; I agree there too.
As a side note, for my next change on my Explorer I am going to try Castrol GTX Ultraclean. It is a syn blend. They make some pretty bold promises about both preventing sludge and cleaning up old sludge.
My Explorer doesn't get driven much though, so it will be a while before I change it again, even longer until the first change with the Castrol in it.
I would also agree with shorting up the OCI's. You are talking a few extra bucks, not a big deal.
 
Rotella T6 is about 20-22 dollars for one gallon.

You could have just bought Mobil 1 on rebate every spring and fall and halve the OCI to get the same or better results; this after setting up slickdeals alerts to make sure you don't forget.

Or if you have a Tractor Supply nearby, buy the 5 gallon Traveller's buckets from them.
 
This engine looks seasoned. Or "stained" I don't see any heavy gummy deposits, carbon or sludge. And seeing how this engine was initially recommended to use conventional SJ-SL ILSAC engine oils and may have for much of its early life it looks great.
 
Originally Posted by danez_yoda
You have been running the Rotella T6 the entire life?
That said an good high detergent oil is Pennzoil Ultra. A ran that in a new "to me" van I got and the oil turned black after about 1000 miles. Next OCI it tool about 2000 miles. I was thinking the PUP was crap but nope it was cleaning the old sludge out. After about 4 5K OCIs then it was coming put the sump like pancake syrup colored. No inky black at all. Just a dark amber tent.


I second PUP cleaning ability. For the past few OCIs oil is gradually cleaner for the same no of miles on my engine.
 
Last edited:
Thanks everyone,
I have a '95 Taco, same motor, something went wrong in the engine ventilation system and it completely filled with sludge/carbon , I pulled a valve cover and the only clear space was where the cam lobes pushed it aside, and I did not want the '04 to go that way. I'd just used regular dino oil on that, but I did buy it with 60K and replaced the motor at 197K.

I bought the 04 Taco off lease in '08 with about 100K and have been using the same oil (T6) , 240K now.

I also run the T6 in my 91 Ford 460 gas RV, it gets changed every 4000mi though, ie every time we take a long trip with it I start with fresh oil and filter.
I used to run Mobil-1 in it, but went to the T6 for the much higher Zinc and Detergent levels to protect the cam in the Big Block. It also spends a lot of it's time
at full throttle when climbing mountains, some times 30 minutes with the pedal to the floor and in 2nd gear, and even some times in 1st. The tacoma never sees that.

I also help out the RV with a 1/2 bottle of Rislone, keeps the lifters quiet, I'd had one start ticking at idle and that went away after the Rislone and coincidentally
changing the thermostat back to the spec 192F, it had been 180F. Dropped my cruise oil pressure from 80PSI to 75, but idle is still around 40.
I only got the tick after running for a couple hours at highway in the Texas heat, we'd hear it when we stopped for gas, bumping idle to 1000 would quiet it.

We also service a 55kW Generator with a 3.0L John Deere turbo with the T6. So it's kind of been my go-to oil.

It sounds like for the '04, I should jump over to a something like the Pennzoil for the next couple changes at 7500 and then go to a shorter cycle.

I was a little taken back by the varnish levels after looking at an Franklin airplane engine that has about 500hrs and is absolutely clean, but the oil is black.
(but that's a whole 'nother story
smile.gif

TD
 
Originally Posted by MutantGarage
Thanks everyone,
I have a '95 Taco, same motor, something went wrong in the engine ventilation system and it completely filled with sludge/carbon , I pulled a valve cover and the only clear space was where the cam lobes pushed it aside, and I did not want the '04 to go that way. I'd just used regular dino oil on that, but I did buy it with 60K and replaced the motor at 197K.

I bought the 04 Taco off lease in '08 with about 100K and have been using the same oil (T6) , 240K now.

I also run the T6 in my 91 Ford 460 gas RV, it gets changed every 4000mi though, ie every time we take a long trip with it I start with fresh oil and filter.
I used to run Mobil-1 in it, but went to the T6 for the much higher Zinc and Detergent levels to protect the cam in the Big Block. It also spends a lot of it's time
at full throttle when climbing mountains, some times 30 minutes with the pedal to the floor and in 2nd gear, and even some times in 1st. The tacoma never sees that.

I also help out the RV with a 1/2 bottle of Rislone, keeps the lifters quiet, I'd had one start ticking at idle and that went away after the Rislone and coincidentally
changing the thermostat back to the spec 192F, it had been 180F. Dropped my cruise oil pressure from 80PSI to 75, but idle is still around 40.
I only got the tick after running for a couple hours at highway in the Texas heat, we'd hear it when we stopped for gas, bumping idle to 1000 would quiet it.

We also service a 55kW Generator with a 3.0L John Deere turbo with the T6. So it's kind of been my go-to oil.

It sounds like for the '04, I should jump over to a something like the Pennzoil for the next couple changes at 7500 and then go to a shorter cycle.

I was a little taken back by the varnish levels after looking at an Franklin airplane engine that has about 500hrs and is absolutely clean, but the oil is black.
(but that's a whole 'nother story
smile.gif

TD

What were the oil change intervals on the 95 that sludged up?
 
About once a year/7K, Bought it in 2000, I was driving it to Houston every week for the last year before I opened it up, It's pretty easy to change compared to the '04 PreRunner.
I have to take off a couple of skid plates to change the oil on the 04, so it doesn't get changed as often
smile.gif


The 95 was running OK, but starting to make a lot of valve click noise in the heads, so I pulled the passenger side cover,
thinking I'd re-shim the valves, and what a mess! Someone gave me a link to there being a problem with 95 and earlier Toyota V6
sludging up due to breather passages in the valve covers clogging up. I've still got that motor, I bought a rebuilt 98 4Runner motor for $800
on e-bay and swapped them in 2006. Kept the old one around as a core. if I ever need another.
If I get 10 more years out of the 04, I'll probably go electric by then. At least for my Daily,
The RV will get replaced by a diesel rig and the Airplane (when it's ever done, it's an Experimental) will still be AvGas for a while.
maybe someday there will be used aviation diesel pistons that are affordable and burn Jet-A
 
Originally Posted by MutantGarage
About once a year/7K, Bought it in 2000, I was driving it to Houston every week for the last year before I opened it up, It's pretty easy to change compared to the '04 PreRunner.
I have to take off a couple of skid plates to change the oil on the 04, so it doesn't get changed as often
smile.gif


The 95 was running OK, but starting to make a lot of valve click noise in the heads, so I pulled the passenger side cover,
thinking I'd re-shim the valves, and what a mess! Someone gave me a link to there being a problem with 95 and earlier Toyota V6
sludging up due to breather passages in the valve covers clogging up. I've still got that motor, I bought a rebuilt 98 4Runner motor for $800
on e-bay and swapped them in 2006. Kept the old one around as a core. if I ever need another.
If I get 10 more years out of the 04, I'll probably go electric by then. At least for my Daily,
The RV will get replaced by a diesel rig and the Airplane (when it's ever done, it's an Experimental) will still be AvGas for a while.
maybe someday there will be used aviation diesel pistons that are affordable and burn Jet-A


Whenever I have gone close to 7k on my vehicles it was racked up in about 2 months. A solid 2 hours on the highway every day to go to work. If it was 7k over a year I'd expect some buildup but obviously a pcv problem would make it a whole lot worse.
 
I'm not seeing the sludge and the film you're seeing is not measurable. Rock on with what you're doing. 240k behind it, I'd say well done.
 
Last edited:
Just do 7500 oil changes, any good syn will be good.
Yes I would switch to gas truck and 7500 oci
 
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