1MZ-FE is non-interference

Dec 19, 2007 12 Replies

All: I just received this email from a Service Coordinator at my local Toyota dealership and repair place. It's now official that my 1998 Toyota Avalon engine is non-interference. Thank you to everyone who helped me with this question. Here is Mira's email below.



Keith Lee


Hi Keith, Your 1998 Avalon has a 6cylinder engine and a timing belt, this constitutes that your engine is non- interference. If you have any further questions please respond to this email or feel free to call us directly at the phone number listed below.



Mira Winsby - Service Coordinator



I believe Keith is using the new information to justify his logic that because it took so many years for the car to log 73K miles, it "wasn't used much", so those miles are somehow different than if they had been driven in a shorter period of time. Of course, that's silly, but that's what he was saying in his other thread.

Here's his original logic:

All: Thank you to those of you who answered my initial question. I have almost

73K on this Avalon; but, it was rarely driven by the previous owner so I am satisfied that I won't need the timing belt and water pump changed for awhile.

Perhaps. It used to be SOHC-Interference, DOHC=N-I.

Yes, your 98 1MZFE Avalon is non-interference. But for Mira to say it is because it's got a timing belt is plain WRONG. Some Fords and many Hondas use timing belts and are INTERFERENCE engines!!

that your engine is non-

or feel free to call us directly at

Right on Jeff. It just tells you the kind of "service coordinator" quality (or lack of) we are dealing.

The service coordinator provided the correct answer (that the 1MZ-FE engine is non-interference) but provided the incorrect reasoning for the answer. It used to be that Toyotas with timing belts were all non-interference, and Toyotas with Timing chains were interference, but that is no longer always the case.

Ray: How do you know it is non-interference? I have seen some websites say yes and some say no. I have talked to some former auto technical people who say it isn't. Just curious about your info. Thanks!

Keith

and some say no. I have talked

your info. Thanks!

Ray O is a former employee of Toyota who donates his time and energy to this newsgroup among many others.

So on this note, is there a comprehensive list of Toyota's or any vehicles where you can find out if they're interference or not?

I have a 2002 Corolla -- it's a chain -- is it interference?

Thanks,

Steve

Good question! I don't remember where I heard that tidbit, (I think it was from one of the Toyota Master techs who used to frequent this group) and since it is the same engine in our Avalon, I retained it. That said, I don't recommend waiting to find out whether I am correct or not! ;-)

I don't know whether the 2002 Corolla has an interference engine or not, but my guess is that it has an interference engine.

The distinction of belt = non-interference and chain = interference is not universal across automakers. For example, most Hondas have interference engines, whether or not they have a belt. Toyota used to use make engines with belts free-wheeling, but I don't think that is still always the case.

The two main reasons for using a belt over a chain are initial cost and noise reduction. Advancements in chain and chain tensioning technology have made them almost as quiet as a belt, and the cost is not that much more, so Toyota has started to use chains more often in newer engines.

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