My husband says that the reason our 2002 Toyota Highlander burns oil so fast is because of a design engine flaw and therefore, it does not need to be seen by a mechanic. He puts a quart of oil in it whenever we take a 3hr+ trip. He says it doesn’t burn as much oil in regular around town driving. What do you think? Is there an engine design flaw. It has about 100k miles and is a 6 cylinder.
What would that design flaw be? A restricted crankcase vent system is the most likely cause of such a problem would be a common condition on engines with 100,000 mi.
It is not a design flaw. It should be seen by a mechanic.
I’ve owned various Toyotas since 1976, some for hundreds of thousands of miles, one for 338,000 miles (it didn’t wear out, it got totalled).
Your husband is incorrect, but I know not how to convince him. Sorry.
Some cars do use oil on a regular basis, why is another question, is your consumption of oil higher than 1 qt every 1000 miles? A three hour trip is probably 200 miles or so, and how much oil does it use? If it is a quart that does sound like a problem, but the repair will be expensive. Just out of curiosity how often do you change the oil and filter?
If it’s a design flaw, why don’t all Highlanders use oil this quickly? It should be evaluated to see what the problem is. Whether it’s worth paying to fix is another question. Get two or three estimates from mechanics that you can trust and then decide what to do. Bring the quotes to us and we’ll go over the with you.
The V6 was prone to oil sludging up to 2002.
http://www.autosafety.org/toyota-oil-sludge Toyota covers oil sludge related engine repairs up to 8 years from the purchase date.
I think part of the problem was the 7.5k mile change interval. Toyota now recommends a 5k interval (at least for my 06 Sienna). What is the rate of oil consumption? Toyota considered up to 1 qt/1000 miles of oil consumption normal. Check or replace the PCV valve, a malfunctioning valve can increase the rate of oil consumption.
There’s a number of things that can cause excessive oil consumption not related to a design flaw. Overheating, irregular oil changes leading to sludged/coked piston rings, abusive driving habits, failure to service the PCV valve, chronically running the engine oil level down too low, and even improper break-in procedures when the truck was new.
Run a dry compression test as a first step and a wet test as the follow-up. Since a compression test or leak-down test is not 100% definitive it is possible to have a ring problem and good readings at the same time. However, those tests are the best available.
Odds are that it’s not a design flaw at all and is related to one or more of the above causes.
He’s mentioned that there is a problem with sludge build up in some V6 engines and that it would be too expensive to fix. He usually changes the oil every 5k miles and replaces the filter to try to keep it from getting too bad. I think one of the posts mentioned that and that Toyota may honor some kind of quasi-warranty regarding this problem. However, we bought the car used, so I’m not sure if we could take advantage of that or not. Anyone know?
-Are you sure it’s burning it and not leaking it?
-Some cars just use more oil than others. At the rate you describe, you should be seeing some blue puffs out the tailpipe, at least at startup.
-Switching to a full-synthetic may reduce the oil consumption rate and help reduce sludging.