June 3, 2009
Hello,
I have a 2002 Toyota Highlander with approximately 112,000 miles.
Approximately 1.5 years ago, it started to burn oil. I had to start adding oil between oil changes, which was new. It was still under the 100,000 mile warranty. I took it in to two different Toyota dealers and mentioned it several times. They said they would top it off and keep an eye on it. Unfortunately, they did not document my concerns until after the warranty expired. One oil change shows that it was a quart low, while still under warranty.
Recently on a long trip, the engine light came on, as well as the VSC light. The car vibrated and the engine was miss-firing and running very rough.
I took it to a Toyota dealer. I filed a claim with Toyota regarding a known issue of oil gelling. After the dealer did a diagnosis, approved by Toyota, they determined that the problem was not the oil gelling issue and closed the case.
The result of the dealer’s diagnosis is that the car needs to have 2 exhaust valves replaced. Their estimate for repair also includes over 9 hours to rebuild a head assembly, 1 gasket set, oil filter, oil, coolant and head bolts. $1800.
They admit that this probably will not resolve the oil burning problem.
There are complaints about oil burning on the internet, what is the remedy?
I'm not sure what Toyota's standard is on this, but 1 quart of oil over a 5000 mile OCI isn't a warranty concern, or really a concern at all. This could be happening on a brand new car, and Toyota would likely do very little about it. It's not ideal, but no auto manufacterer will do much about this.
Your burnt exhaust valves might have been caused by too little oil, which might have been caused by the oil burning, but that's not likely. One quart low is just not low enough to have parts starved for lubrication, at least in my experience. Either the oil level was much lower, or the valves became too tight and weren't completely closing.
Did you take a look when they had the valve cover off, was there sludge buildup? It's almost impossible to clean without removing the heads, so it won't be hard to spot and there's really no way they could have cleaned it without you knowing. Assuming there isn't, you're probably on your own for this repair bill.
For the consumption, there are three places that oil can go. Firstly, it can get into the cylinders via the valve guide seals. This is pretty common on the 3.0 v6's. There gets to be some buildup around the seals which starves the guides for oil and they wear. Then the oil is changed and the detergents in the new oil dissolve it, or the buildup is cleaned out with a treatment and now there is a tiny path for the oil to enter the cylinders. This usually results in blue smoke at startup after sitting for awhile. Secondly, carbon buildup on the piston rings can make them stick and not have a good seal against the piston wall and allow oil past. This is difficult to diagnose and even harder to fix, and will almost certainly be a condition you learn to live with. You can try a treatment like AutoRX to see if you can clean it up, with mixed results. Lastly, the PCV valve or the tubing from it to the intake manifold can become clogged. Once this happens, there is always positive pressure in the engine forcing oil through the breather into the intake manifold and down into the engine where it's burnt. But this usually results in really high oil consumption rates, more than you are experiencing.
So my advice for your oil consumption would be to replace the PCV, it's a 4.00 part and probably 20 bucks to get it changed at a jiffy lube. If you're already paying for the valves to be replaced, have the valve guides on all the cylinders (at least on that bank) replaced. The cost increase will be pretty small. Ask the mechanic doing the job how they look and consider doing the other bank, which they may not have to remove the head to do. And use a quality oil that will have more detergents in it. For example, Mobil makes five levels of oil. Bulk, 5000, 7500, M1 and M1 EP. The biggest difference between them (besides the base stock being conventional or synthetic) is the amount of detergent in them. Mobil puts more detergent into the more expensive oils because they are designed/marketed for extended use. But you can use the higher detergent levels at a normal oil change interval for their enhanced cleaning if you do have a lot of deposits in your engine.
No, more like 2-3 quarts not just one. The dealer told me today that my car's value is zero. No trade in, nothing. He doe not recommend spending the $1800 for the repairs because the oil problem could be very major. He suggests a new car. All because the dealer I first took it to while under warranty did not document the oil usage.
Have you considered having a private mechanic take a look at it?
I have a feeling you're going to dealerships because you think this will be covered under warranty. But I really doubt that will be the case. And if it's not warranty work, you're paying a higher rate for the same level of service you could get somewhere else, and perhaps a bit of a conflict of interest as they seem to want to sell you a new vehicle.
No value is hard to believe. Find a private mechanic and get a cost on a full engine swap, and more importantly their opinion on the condition of the engine. I assume it's the V6, and the dealer is worried they will have to pull both heads and double the 1800 dollar estimate, and you'll walk away from the car. But a private mechanic may be able to put a salvage engine in for a few thousand dollars. And five grand on a new engine is better than 20 or 30 on a new car.
I had this same problem. The problem is witht he engine design. It is really bad and lets the oil sit on top while the engine runs causing sludge. Went to dealer and they want $5000 to fix mine and told me the same thing that my car was worth $0 and should just look into buying a new one. Blue book value is around $10000 so the car is worth something if it is running fine. Total cost for me to fix not through dealer is about $2500 through private mechanic. The main problem is the valve seals. The engine is burning oil because while it is off the oil leaks past the valves into the cylinders. Then it fouls the plugs and clogs up the CAT and messes up the O2 sensor which all pretty much need to be changed if the problem has been going on for a year or so. The cost of the repair is not in the parts which you can probably get for $500 or so depending if you want OEM or aftermarket, it is becasue the fix is so labor intensive. This is one Toyota engine that really has a bad design because everything is not accessable without taking the top valve and cylinders. So the main things you need to do is flush the engine, run a couple weeks with new oil, check to see if the oil turned black or dark, if it did then you need to flush again, and then replace oil again. Use cheap oil during this process becasue you will go through at least 15 quarts of oil. Then use a compete fuel system cleaner to clean out the deposits that were caused by the buildup. If this does not solve your problem or the oil burning gets worse then you need to change the valve seals. Also very important if you are not using synthetic oil you need to start using it. Synthetic oil has a higher heat tolercance so it will not sludge up as quickly as regular oil. This is as far as I got with the repairs for my car due to financial constraints, but the mechanic also suggested to change the O2 sensor, CAT, and exhaust because the oil residue will remain in the CAT and the Muffler and on the O2 sensor which will cause the Check engine light, VSC and Track Off lights to some on in the counsel. Hope this helps and I hope you didnt junk your car.
oil usage is caused by lack of oil changes. the only problem toyota has with their
engines is the owners not changing the oil. every customer i have talked to in 28 years
about their oil usage have the same thing in common. lack of oil changes. word. yspert
There's some truth to that yspert, but the problem with your logic is this. There's no difference in the maintenance habits, on average, of owers of other cars an the 1MZ slugemonsters. No difference to input, but the output is wildly different on these engines. The are significantly worse than average, and they're a product people paid a premium for because it was "reliable" so IMO, thumbs down to Toyota on that one.
If it were mine, I'd be using an off the shelf synthetic every 5000 miles. Any would be fine, M1, PP (a favorite at BITOG), Synpower... whatever's cheapest at the time.
2002 Highlander Oil Burning
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