I have a 1988 4runner with the 3.0 and am starting to think (hope not) that my piston rings are bad.

The truck billows white smoke. It begins about 30 seconds after startup but does clear up as soon as I start driving.

I have also noticed it's using oil, but there no signs of leaks. There is a little bit of oil around the bolts holding the valve covers on.

On top of that, the exhaust has gotten "louder" and it seems to have lost some power. Still drives fine, but it is slow to accelerate.

Could this be piston rings going bad? Is there a way for a newbie to diagnose this?

 

To check the rings you need to do a cylinders compression test. It's quite simple but you need to buy or rent the pressure gauge. However what you are describing could be also a blown headgasket which is typical for the 3VZE engine. When that happens, coolant leaks in the cylinders and it gets burned off when the engine starts causing white smoke to come off the exhaust. Did you check the coolant level? Is the radiator full?

 

 

If the head gasket is blown, coolant gets mixed with the oil. If you change it, you would see the oil has a lighter color, and less viscous. Also check under the oil cap if it looks slushy. You can also try to remove the radiator cap, and start the engine, If you see bubbles coming out it means the gasket is blown. and the pistons are sucking air in the cooling system.

 

How cold has it been where you live? Maybe you are just seeing steam from the exhaust which is typical for a cold engine on a cold day.

Usually oil consumption gives a blue-ish smoke, not white, but can be kind of subjective. Usually if piston rings are pretty bad, you will see some blue smoke when accelerating.

How much oil is the engine consuming?

Is the "Check Engine" light on?

A compression test will give you a good sense of the health of the engine.

 

Thank you for sharing the info about compression test! I've been wanting to do that.

It can get pretty cold here in western North Carolina. It was in teens this morning, so it could very well be at least some steam.

I'm not noticing any blue smoke; maybe just a tiny bit. But the only time I see smoke is at startup, not while driving. I'm adding about 1/4 qt of oil per month.

Two check engine codes: 51 (tps) and 52 (knock sensor)

I did notice last night I have a gnarly exhaust leak right behind the muffler, so I'm wondering if that's not causing some of it.

 

I tried cranking the truck without the radiator cap on to check for bubbles. All I noticed was that coolant spewed up and out of the radiator while cranking. Not sure if this is normal behavior or not.

 

Isn't the proper way to check rings a leak down test?

 

For reference, here is a 22R-E cold start showing normal cold-weather steam from forum member Arlindsay1992; 3VZ-E should be similar:


The knock sensor code 52 probably goes with your symptom of lower power as when the computer cannot make sense of the signal (if there is a signal at all) the computer reduces the timing as a preservation strategy.

The usual culprit for code 52 is bad wiring in the wire "pigtail" that connects to the sensor. The knock sensor wire is shielded to keep electrical interference off of the knock sensor signal. The sensor itself is usually just fine.

I think a compression test and a leak-down test go together well.

A compression test tells us how well each cylinder in engine is sealing and gives us a value to compare to the Factory Repair Manual.

If a leakage problem is suspected, a leak-down test will tell you a relative percent leakage and will help you pinpoint where the leakage is going.

 

Thanks for sharing that video! That looks a lot like what I'm seeing on mine, so hopefully it is just steam.

I'll do a compression test ASAP, but I'll have to read up on how to do a leak-down test.

Yea I bet that knock sensor code is causing some issues...but man getting to that thing is ridiculous. I think I'm gonna try the relocation hack with a new sensor.

 

This screams head gasket issue

 

I sure hope not, but I do know it's almost a given with the 3.0.

The engine wasn't hot while I was cranking, it had been off for about an hour.
I'm trying to convince myself that it is not a HG issue. Coolant levels are still good and I don't smell coolant in the exhaust. Also oil looks normal.

 

double post...and having issues uploading pic from iCloud

 

The head gasket can start leaking slowly as well. That was my experience when head gasket went on my 22RE.
When head gasket went on my 3.L there was little doubt. The head gasket in 3.l had been replaced by Toyota as part of their recall however I am not sure of when. At 150K miles the head gasket blew again. I had it replaced but in hindsight I should have just swapped the engine out for a later model Toyota V6, more powerful, less issues.

 

I am still not completely convinced the head gasket is bad.... yet.....

If you want to make sure that combustion gases are not getting into the cooling system (can indicate a head gasket failure), you can do a cooling system combustion gas leak test.

This test captures any bubbles that might come out of the radiator and indicate weather or not there is combustion gas present.

 

I have no history of my engine unfortunately. The PO says the original motor was replaced with another that had about 8,000 miles on it. I have no proof of that, but if correct, it should be at 45,000 miles now. Hopefully I could get another 50k-100k before HG issues arise...again all dependent on the authenticity of the motor replacement claim