'06 2UZ burning oil + other mysteries, 155-190 psi. Thoughts? (1 Viewer)

[erin]

Hello,

I am working on a friend's Cruiser - 2006 w/ 245K on the 2UZ-VVTi. It's been consuming LOTS of oil for a while, and we finally started digging into it. The engine was opened by a previous owner - no idea why or what was done. Based on the poor timing belt/water pump job I corrected a year or two ago, I suspect this prior engine work is a factor.

What's odd is that based on the oil consumption, I would expect the back of the truck to have oil soot around the bumper or at least have a blackened tailpipe. Neither are evident and there are zero engine leaks. I suspect the cats are fouled b/c it's throwing codes (don't recall them off the top of my head). Regardless, no soot, no smoking on idle or startup, no visible smoke when following on road. It's odd. Thoughts?

We ran a compression test and leak down test (both were run on a cold engine).
Compression numbers (specs from FSM page EM-3: max 199 psi, min 149 psi, <=14 psi difference between):
1 - 178
2 - 180
3 - 174
4 - 180
5 - 155
6 - 175
7 - 185
8 - 190

The leak down test on #5 showed a 54% flow, and it was clearly coming through the intake system (throttle plate held open). This tells me there is something amiss w/ the intake valves. I think I should conduct a wet compression test on #5 to check piston ring integrity. If the number does not change, would it be safe to have confidence the ring is good based on the other numbers? I concede there's no way to really tell until the intake valves are addressed.

We're debating on next steps - in situ engine work (pull both heads) or pull the motor.
Reasons to pull motor:
1. The learning experience and fun of it.
2. The steering rack needs to be replaced.
3. Flex plate should be replaced (long-term starter issues, since corrected, chewed up some teeth)
4. Opportunities for cleaning, addressing some brittle/damaged engine harness connectors, etc.
5. Upgrade opportunities, if any.

At 245K miles, it seems now is a good opportunity to do more engine work than just heads. I'd appreciate any thoughts, insight, suggestions. In situ work or pull the motor?

Options we're considering if pulling the motor:
1. Full stock rebuild - local or ship to an experienced rebuilder.
Anyone have suggestions of good 2UZ-FE rebuilders?
2. Full rebuild w/ upgrades - port/polish? 1UZ connecting rods in case of a future VVTi-compatible supercharger installation? Anything else worth considering?
3. JDM import swap
4. Junkyard swap (disinclined to go this route)

Funds are not unlimited although we're willing to spend some money for longevity, efficiency/power increases, and doing all that's reasonable/recommended through the process. This truck will likely be in the family for decades.

What are your thoughts?
Oil consumption and lack of evidence other than codes and disappearing oil on the dipstick?
Rebuild heads or rebuild motor?
Recommendations on top-quality, experienced rebuild shops.
Pull motor or leave it in place?

Anything I'm not thinking of?

Thank you,
Erin

 

[jerryb]

I can't think of any reason not to pull it after reading what you wrote.
2 3 and 4 are enough reasons.

 

[erin]

Thank you, @jerryb . Pulling the engine seems to have some advantages. The next question is how far to go with it and/or find a suitable replacement.

Erin

 

[jerryb]

that's always my question, how far and how much. I spent about 2k on toyota parts, not including exhaust manifolds. But including a full SAI delete. and some welding. So 1500 or so at random dealers and partsouq. Someone could obviously spend less.
I will probably have this truck until I die.

 

[newbielx470]

If an engine is not burning oil nor having vibration, is it ok to keep driving with one cylinder having low compression number? (e.g. 30% lower than the other 7 cylinders)

 

[jerryb]

Depends on you age, responsibility, income, and risk aversion.

Google

Search the world's information, including webpages, images, videos and more. Google has many special features to help you find exactly what you're looking for.

www.google.com

 

[erin]

@newbielx470, I don't know of many instances where a cylinder could have low compression and not be burning/losing oil. Your fuel economy (typed w/ a smirk after just putting several hundred miles on my LX) would certainly suffer as well. The catalytic converters probably won't like it either. All food for thought.

 

[2001LC]

Cold compression test is for a non running engine. Which I see number closer to 150 PSI cold.

Your numbers look high to me, for a cold engine. Which if fuel pump on, numbers will come in high. As fuel takes up space in cylinder.

Compression test need to be done with hot engine, to get viable readings. FSM specs are based on hot. They're also done with fuel pump disconnected, throttle body open and battery (12.7v+) cranking engine at minimum if 250RPM.

Leak down is usually done after wet test, to further delineate. Leak down test can be tricky to as we turn the crank by hand, to get test cylinder to TDC, both valves closed.

I'd run test again, by the book (hot). If #5 still low and PSI does not come up wet, and leak down still ~54% in #5 and hearing at TB. Consider running a camera in to inspect intake valve.

 

[Zjohnsonua]

@erin, given all the info you posted I'll vote to yank and replace the engine for the following reasons:

I'm assuming finances are the priority here, and the truck needs to get back on the road sooner rather than later.

Cold or hot, that huge gap down to cyl 5 is not good. Run the hot test as 2001LC recommends, but do not expect to see healthy results.

Why the opposition to #4? I'll take a known running, low mile factory-built engine over a rebuilt/modified one every time if things are planned to stay at or around stock. People underestimate the value of the tooling and processes that go into factory built driveline parts. These are some of the most venerable engines ever built so long as they are maintained. Poke around a bit and you can find a Tundra/Sequoia/4RNR engine for fair prices.

Head work (or heads in the worst case), the build kits, and the while-you're-in-there's add up in a hurry. And that's before the labor is piled up.

Some advice - the 2UZ was not intended to be pulled on its own from a 100. I've done it once. I will not do it again. Pull the whole driveline - it was dropped in as a unit - pull it out as one. Yes, it's a long driveline, but it comes out beautifully this way. Yank the hood, pull the crossmember, then pull the front tires to get the nose down a bit.

 

[jerryb]

Some advice - the 2UZ was not intended to be pulled on its on own from a 100. I've done it once. I will not do it again.

best advice in at lest six months on mud. I regret that decision to separate.

 

[erin]

Cold compression test is for a non running engine. Which I see number closer to 150 PSI cold.

Your numbers look high to me, for a cold engine. Which if fuel pump on, numbers will come in high. As fuel takes up space in cylinder.

Compression test need to be done with hot engine, to get viable readings. FSM specs are based on hot. They're also done with fuel pump disconnected, throttle body open and battery (12.7v+) cranking engine at minimum if 250RPM.

Leak down is usually done after wet test, to further delineate. Leak down test can be tricky to as we turn the crank by hand, to get test cylinder to TDC, both valves closed.

I'd run test again, by the book (hot). If #5 still low and PSI does not come up wet, and leak down still ~54% in #5 and hearing at TB. Consider running a camera in to inspect intake valve.

@2001LC, great suggesting re hot test. I did not know how long it would take so opted to do it cold for consistency. Plus, it's HOT in Arkansas, so I was not wanting to be working in a hot engine bay. Now that I've done it, I can repeat w/ a hot engine relatively efficiently.

I agree that the numbers look high. I was shocked by the 180's and 190's, particularly w/ the oddities this engine is displaying. Perhaps things will change w/ a hot test.

TB was open, and all injectors were disconnected. We did not disable the fuel pump although effectively isolated it from the test. I was watching the gage and not sure of cranking RPM. Battery was good, and we had a charger on standby if needed.

We put each cylinder at compression TDC by using a thin rod and stopping just as upward motion started to change direction. It worked well.

I'll get my hands on a camera pending more testing. My hunch is that the head(s) were off this engine as some point and perhaps the quality of work was not ideal (based on the very poor water pump job I corrected). My initial thoughts are an issue w/ the #5 intake valves. We'll see what more testing does.

Any thoughts on the mysterious oil consumption w/out smoking or soot? I'm perplexed.

Thanks for your suggestions, and I'll report back.

Erin

 

[ramangain]

You mentioned LOTS of oil being consumed. Can you quantify that please?

 

[erin]

@erin, given all the info you posted I'll vote to yank and replace the engine for the following reasons:

I'm assuming finances are the priority here, and the truck needs to get back on the road sooner rather than later.

Cold or hot, that huge gap down to cyl 5 is not good. Run the hot test as 2001LC recommends, but do not expect to see healthy results.

Why the opposition to #4? I'll take a known running, low mile factory-built engine over a rebuilt/modified one every time if things are planned to stay at or around stock. People underestimate the value of the tooling and processes that go into factory built driveline parts. These are some of the most venerable engines ever built so long as they are maintained. Poke around a bit and you can find a Tundra/Sequoia/4RNR engine for fair prices.

Head work (or heads in the worst case), the build kits, and the while-you're-in-there's add up in a hurry. And that's before the labor is piled up.

Some advice - the 2UZ was not intended to be pulled on its own from a 100. I've done it once. I will not do it again. Pull the whole driveline - it was dropped in as a unit - pull it out as one. Yes, it's a long driveline, but it comes out beautifully this way. Yank the hood, pull the crossmember, then pull the front tires to get the nose down a bit.

@Zjohnsonua, thanks for the vote! I'm definitely leaning that way as there's so much to be gained from doing so. And, yes, we will CERTAINLY pull the drivetrain as a unit. We plan to pull the hood, radiator, grill, etc, and take advantage of the opportunity to clean, inspect, etc. The A/C is currently not working, so we'll pull the condenser as well to thoroughly clean the fins, etc. I enjoy tearing things down and look forward to it.

I never liked stabbing engines onto transmission input shafts when I did it in 40's and other rigs long ago. I have no interest in doing it in this.

I had not thought about pulling front tires to lower the truck and will do so. Good thought!

I agree w/ your thoughts re #4. My issue is finding a worthy replacement in a timely fashion. I have some JDM importers to contact as those engines are typically relatively low mileage and might fit the bill (1UZ and 3UZ's are commonly imported; 2UZ not so much). I wholeheartedly agree that a factory-sealed engine is a great thing. We have not ruled that out.

Other thoughts about rebuilding would be the opportunity to install 1UZ rods in case a supercharger is ever added in the future. I know the 2UZ rods are good although they seem to be the weak point. It's unknown if this truck will ever see a SC although if it's little extra cost for beefier factory rods, might as well go for it. We had similar thoughts about any porting/polishing opportunities on the heads. Again, low-mileage factory-sealed motor is compelling. An opportunity to rebuild and make some mild improvements is also a good option. She'll be going back together w/ DT headers and a more efficient exhaust.

Finances and timing are not critical. We have time (not my friend's only vehicle), and he's interested in spending money as needed. We're not going to go crazy, and he's already making a list of the "do it while we're in there" things. That list is growing, and b/c this vehicle will likely be around for decades, money well spent will pay off. We'll be doing all work but the actual rebuild, so labor is not an issue.

Any additional thoughts/advice?

Erin

 

[erin]

You mentioned LOTS of oil being consumed. Can you quantify that please?

@ramangain, I would not consider my buddy overly anal or scientific (like I am), and he's not exactly sure. We suspect it's in the 1 quart per 1,000 miles range. I consider that pretty horrible. My '06 LX barely moves on the dipstick between changes.

Again, w/ that consumption, I would expect some proof - smoke on startup or under load, soot on back of truck, etc. Nothing, nada.

It's odd, for sure.

Erin

 

[ramangain]

Thought about sending an oil sample in for analysis to try and get clues? Maybe some higher than normal specific metal content?

 

[erin]

Good thought. I just received some sampling kits from Blackstone and could easily use one for this truck. I shied away from it since we'll be doing major work regardless. It would be interesting, regardless and would certainly add some data to our investigation.