When does oil use indicate a need for repair?
My 1997 Toyota Land Cruiser has 193,000 miles on it. Weekday travel is 30-50 miles per day, evenly split between highway and city driving. Weekends usually include 60 to 100 miles of driving with a few minutes of maneuvering towed trailers/equipment in steep terrain. Naturally, oil use has increased with age and is particularly high during the heavier weekend work. Oil usage has declined steadily from 733 miles/quart (Summer 2007) to 282 miles/quuart (Spring 2009).
I understand the short-term financial math favors paying a few bucks for oil over an expensive repair like changing the head gasket, but at what point should I consider making a repair? I have no interest in replacing the vehicle, as it meets my needs and has provided better value than any other I have ever owned.
When does oil use indicate a need for repair?
At near 200K miles you’re going to be burning some oil, as you said. There’s generally two ways this happens, worn piston rings, and leaking valve seals. Both are expensive to fix. The ring problem will require an engine rebuild. The valve seals will require a cylinder head reconditioning. If you really love this vehicle and it’s still in good shape, spend a few thousand and rebuild the engine.
282 miles/quart is pretty heavy. If it’s really burning oil the motor should smoke some in spite of the cat converter. Are you sure it’s burning it all?
A clogged PCV system could cause it to leak more, but only running under load.
With that many miles on the engine, you might want to try a product called RESTORE. This is formulated to fill in the fine scratches in the cylinder walls that allow oil to get past the rings which gets burned in the engine. I’ve used this product in engines where oil consumption reached the level you’re talking about. And if it didn’t completely stop the oil consumption, it reduced it dramatically.
There are a few small drops of oil on the garage floor. Smoke is only visible on starup (especially if cold), and occasionally under load.
Try this: On an empty piece of highway accelerate strongly (~half throttle) from 50 up to ~60-65 mph, coast back down to 50, then lay on the throttle again and look behind you. If you lay a smoke screen it’s the rings.
I once saw a car ('76 Chevy 250 straight 6) with a clogged PCV port. It would pressurize the crankcase and leak oil in several places, but only when cruising on the highway. There was oil all over the place under the hood, but you couldn’t tell where it was coming from when the car was standing still.
Tried that seveeral times, including level road and uphill, on a bright, clear day. Absolutely no visible trace of smoke. The exhaust does have an oily smell sometimes upon startup when it’s cold. Also, the insulation on the underside of the hood does have a light oily residue. There is a thin film of oil/grit on the passenger side of the valve cover (more in some places than others), but it does not seem excessive to my untrained eye.
Any harm in trying RESTORE, as recommended below by Tester?
“Any harm in trying RESTORE, as recommended below by Tester?”
A good thread is like a stew. I tossed in some celery, Tester tossed in some carrots…
Thanks. I’ll give it a try.
While I’m sure some is passing the rings, if it smokes on start up, especially enough to have an oily smell, you likely also have well worn valve guide seals. What happens is that the oil that lubes the camshafts drains down into galleys in the head to return to the crankcase, but with worn valveguide seals when you shut down it’ll leak past the seals and onto the backs of the valves, into the cylinders where they’re open, and burn when you start up.
The worn valve guide seals also allow oil to be drawn into the cylinders and burned especially under high cylinder vacuums like when you decelerate. That’ll cause excessive oil use but you may not see it because the cloud will be dispersed as you move down the road.
The good news is that valve guide seals are reasonably replacable without a rebuild.
I also agree that you have some blowby due to worn/tired rings and cylinders. That’s allowing excess pressure to build in your crankcase and forcing oil past seals and gaskets, resulting in the other oil drops and coating you’re seeing as well as oil usage. This can be exascerbated by a plugged PCV valve (as already suggested) so checking that is a good idea.
The bad news is that worn out cylinders and rings can only be repaired via an engine rebuild. $$$$$$$$$$
Since you want to keep the vehicle you may want to begin searching for a boneyard engine. As long as you keep oil in it it’ll keep running like it is for awhile, so it’ll give you time to look.
What are the pros/cons of a boneyard engine (if I can even find one that’s suitable) vs. rebuilding the current engine?
Have you tried high mileage oil yet? I am about to try this oil on my 97 Rav4.
The pros are cost. It’ll be far less than a rebuild or rebuilt.
The cons are risk. Even of the engine has a money back guarantee, if you shoehorn it in and it turns out bad the guarantee will only give you money back on the engine. The labor and misc is the price you pay for taking the risk. If it works, you win. If not, you risk some loss.
Another option would be to replace the valve stem seals (and PCV valve) and accept the rest of the wear. That would likely reduce your oil usage considerably (based on my understanding your description) and you’ll probably get many more miles out of the engine.
If you go with a rebuild option, unless you’re doing the work yourself and are ambitious and patient I recommend looking for a crated rebuilt “long block”. A “long block” has the head included and you’ll need that. A “short block” comes headless.
Thanks for all the good info!
Ouch, but thanks!
Not yet. I just bought some last week, but I am still using up the regular oil.
Your Land Cruiser is the last year Toyota installed the legendary FZJ80 “straight 6” motor - essentially a “tractor motor” and built for 300k miles/25 years. Now they all come with V8’s. That said, maintenance and repairs are needed. I would fix it - these rigs hold their value, are functional and are a blast to drive. My Toyota Dealer said they could “rebuild” the motor for $5000 - and I would haggle or walk.
Thanks for the info. It’s always good to have a price reference. I do love this truck, and even $5K is not a bad value considering how little I have spent on repairs over the past 10 years. (I bought it at age 2 with 70,000 highway miles on it already.)
I’m just curious as to whether or not you had the engine rebuilt. I also have a 1997 Land Cruiser which has been the best vehicle I have owned. It has no rust and I would like to keep it as long as possible. Mine is burning/using oil as much as yours and I’m wondering when/if I should pull the trigger. I would like to hear about your experience. Thanks much for any info you can share. Regards.
Not yet, but it will have 200,000 miles within the next week or so. I hope to find time soon to start obtaining some estimates. I will post info when I finally get around to it, but it may still be a few weeks.