2001 Toyota Corolla



June, 20, 2008 AT 8:20 PM

Engine Mechanical problem
2001 Toyota Corolla 4 cyl Front Wheel Drive Automatic 76000 miles

I have a 2001 corolla that I have only owned 2 months so I can't speak of it's history. It uses oil, quite a bit in fact. One trip of 150 highway miles burned 1 quart. A couple weeks later, a 500 mile trip burned 1 quart. During that last trip, the check engine light came on. No oil appears on the driveway and it doesn't appear to burn oil when we just go around town with it (though we might not drive hard enough to notice it).

Toyota dealer says it is the piston rings, but his diagnosis was not really based on many facts. He said it smokes, but I don't see that. He said he pulled the valve cover and everything looked ok so the only way out is for the oil to get past the rings. He want's $4k for an engine replacement.

I took it to somebody else and he said nothing is wrong with the car (I haven't gone back to him with the check engine light on). He said some oil burn is ok and suggested heavier oil (even though Toyota calls for 5w-30). I started topping the engine off with heavier oil just to see what would happen and that was during the 500 mile trip when the check engine light came on. May or may not be related to me using 10w-40.

I took it to yet another guy who I trust more and he did a compression test. The 4 cylinders are 138, 138, 150, 155. He said that is a problem and he looked up some stuff on the computer and said the corolla specs are 217 max and 145 min. He also checked the PCV valve which he pronounced ok by taking it off and shaking it. It rattled so he said it's ok. This guy also read the check engine problem - it's P0420. This means it's either the catalytic converter or O2 sensors. He's guessing the catalytic converter because I am sending oil down the tailpipe and the catalytic converter has burned itself up trying to burn that oil.

Looking for some help, some suggestions. How do the compression numbers sound?


10 Answers



June, 20, 2008 AT 9:02 PM

I took it to yet another guy who I trust more and he did a compression test. The 4 cylinders are 138, 138, 150, 155. Is this the wet test? If so the compression is too low- Normal compression up to 218psi with 20% tolerance allowable-



June, 20, 2008 AT 9:05 PM

Code 420 is cat low efficiency and is caused by a bad cat converter not o2 sensor problem. Vehicle has low miles, another option is you have carbon build up on the pistons and valves and possibly piston rings. If you have a top engine clean done properly it will remove alll the carbon from the top end and quite possibly free up those sticking piston rings. Just a suggestion and would be my next course of action.



June, 20, 2008 AT 9:39 PM

Thanks for the fast response.

Rasmataz - I don't think it was a wet test. I didn't ask, but since the guy knew the story, I doubt he was trying to get high readings and pull one on me.

Mastertechtim - re: 02 sensors. I got that from the diagnosis flow chart for the 420 code. It says check o2 sensor 1, then o2 sensor 2, and if they check out ok, replace cat converter.

Re: sticking piston rings. Are you saying the compression could be low because there is build up causing the rings to stick and hence slow down the piston which would drop compression? Where is the oil going if the rings are sticking?



June, 20, 2008 AT 11:00 PM

Get your mechanic to do a compression check both dry and wet and follow it with a cylinder leakdown test and comeback with the results. If you have a problem with the rings or cylinder wear it will leak right thru then get burned up in the combustion chamber- Valves guides/stems and seals anything is possible to leak inside the chamber-



July, 24, 2009 AT 12:07 PM

Oil burning is probably the most common issue in an 98-02 Corolla. Everything you're describing is some of the same issues I've had. I've got about 150k miles on my Corolla and haven't done much (as far as taken to mechanic) to do anything about this issue besides replace the cat when the CEL came on. I have used engine cleaning oil additives and they can do a bit to help clean up the engine but aren't a professional cleaning job. Piston rings is the most common answer for why this is happening, but I've heard other responses as well. If you're concerned with it then I'd take it to a mechanic but I can say that as long as this has been happening to me.I probably won't take it anywhere to have it cleaned anytime soon. Regardless, make sure you keep the oil levels within tolerance (3.7Q is what the engine is supposed to have in it apparently).

Here's the list of things I've tried: -Wal-Mart Injector cleaners
-Engine Flush
-heavier oil
-lighter oil
-full synthetics
-plain dinosaur oil
-Auto-RX (this is what I'm currently on)

Of all of them, the Ceramizer increased fuel economy and seemed to increase HP (look it up and you'll find it may help with your compression problem).
The Engine Flush seemed to do the most work in the least time (run for 5-10 minutes before you change oil at idle speed after adding the flush to your oil reservoir) but only made a difference for about 2 weeks after each change.
Full Synthetics helped to keep the engine quieter, while it also seemed to burn much more quickly.
Lighter oil seems to burn more but also seemed to keep the engine feeling slightly more peppy.
Heavier old didn't burn as quickly but made my car harder starting in the colder months.
CD-2 is an oil detergent and did seem to help a bit; I ran it in my car for about 3 weeks and then changed the oil (and found the oil DID come out very black and the oil filter WAS heavier than the control filter on my other '01 Corolla-indicating higher amounts of debris trapped) at 1400 miles since last change (yes, changed it VERY early).
CerMet was snake oil and I wouldn't recommend (ounce per ounce it's about the same price as gold, or was when I bought it).
Injector cleaners didn't do a thing.
The Auto-RX has only been in my car for about a week now so it's too early to tell if I bought more snake oil or not.
And the plain dino oil? Why buy the expensive stuff if it's just gonna burn off anyway? =]



October, 19, 2010 AT 12:56 PM

I have the same issue. I'd like to know how the Auto-RX worked out. Am also considering Valvoline Max Life Oil additive.



October, 19, 2010 AT 1:24 PM

The Auto-Rx helped for a little while, but I think it also made things a little worse too. I noticed after I used it my engine seemed a little better, but now it's burning MORE oil than before, and I had spent the extra bucks for Royal Purple this time (you can understand why I'd be a little upset that my car burned this stuff up).

I'm getting ready to take the engine apart and replace the rings, pistons, maybe get it bored sleeved, and honed, replace the cylinder head, and new cams. When I do this in the next month or two I'm sure I'll probably get a chance to snap a few photos and see what it looks like is going on inside the engine.



October, 22, 2010 AT 1:51 PM

I've been losing oil for about 2 years on my 2002 Corolla. I figured out it was happening after receiving this car as a gift at about 90K. I probably drove it more than 1k miles though before I knew I had an oil loss issue (dipstick was dry). I've been adding around 1 qt oil per tank of gas for over a year. I had started to use 10w40 and 20w50 to lessen the loss (which I now know was really dumb in terms of engine protection even though it worked). Last week the car crapped out (no compression on one cylinder and half on another) at 110K.

I took it in and the mechanic suggested replacing the engine with a used engine that they are able to get from Japan that had 29k on it. It was a hard decision but after doing some research (and suspecting there was a design flaw somewhere) I decided to have the work done ($3600 parts and labor).

But I kept doing research and finally figured out exactly what's going on. The piston on the left is the redesigned one. The piston on the right is the poorly designed one. Those four holes clog, the oil has no where to go but up and over and that's where the oil loss comes from.

The only things I have read that may have some benefit other than getting the better piston design are: 1. Sean Foam treatments on a regular basis might help. But I'm guessing only if you start early.
2. Highway driving exacerbates it. That is my experience and that of lots of other people. Maybe it only occurs at higher rpms. I'm thinking about never driving over 60 when I get it back.
3. Changing the oil early. I'm probably going to do it every 3k now like clock work.

If I knew a week ago what I know now, I would sell the car for $1200 (I found a mechanic who wanted it). But I decided before getting all the facts to have the work done and even though they haven't finished, I'm committed. So I'll have a 29k engine on a 110K body and I'll do what I can to minimize the piston issue as much as I can.



October, 22, 2010 AT 7:49 PM

So does your new engine have a different cylinder head and rod set? Looks like the piston is longer and would be a danger to valves at the least.

Just wondering!



October, 22, 2010 AT 8:39 PM

That pic is nothing to do with my new engine. It's just a pic I found on another site that I thought was the old design and the new design. But it actually isn't. It's the old design and something else. The PDF is more useful.

The engine my mechanic is putting in has the same faulty pistons which is why I'm regretting having given the go ahead. But I didn't know what I now do and neither did my mechanic. This information should have been much better publicized considering how many Corollas are out there with this issue.

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