So I have been reading all about the sludge issues in these 1MZFE engines and understand that a lot of engines were susceptible to sludge. What I am having trouble figuring out is how common is actual failure of these engines due to sludge? One engine in 10,000? One in 10? I understand that a lot of factors including maintenance and driving conditions affect the odds of developing an issue, but am just curious if anyone has a rough idea of how common this ultimately is, all things considered.

Thanks!

it is not common. the majority of cars on the road do not have it.

the power of the internet is in exaggerating problems. the majority of toyota owners are happy about reliability of their engines/vehicles.

those few who get the issue will post about it everywhere so it seems like a common problem when its not.

I have owned three Toyotas in the past and have always been impressed by them. So the sludge issue was really a surprise to me. I just bought a 2002 ES300. It has 150K miles, but runs perfectly. Then seeing the reports of sludge made me doubt my decision. Since everything else about the car seems to be well cared for, I am also guessing that the regular maintenance also happened even though I don't have maintenance records. Let's hope I'm not wrong.

But yes, the internet does have a way of blowing things out of proportion.

Thanks!

The sludge issue is not that bad, it is only a concern for people who dont maintain their car. Internet amplification at it's finest.

Change your oil on time and don't worry about it.

BTW, nuverde, if your ES was manufactured after June 2002, then you have the updated engine with larger oil passages.

According to the sticker inside the driver side door, it was built in 11/01. I know I should just open the valve cover and peek, but I am trying to wrap up work on my Miata and don't want both cars in progress at the same time. Any gotchas that would make it a long task to just look under the front valve cover?

it's very common for people who never do their oil changes which is very uncommon lol

Nope, it sounds like you know your way around cars since you are working on a Miata.

It should take you 20 minutes tops to get your front valve cover off. You might as well replace the gasket though while you are in there.

This is a great tidbit. I have been searching for this for years. I did find some official statements (admissions) from Toyota about the narrow returns which caused the oil to overheat and sludge but I could never find anything about the redesign. Do you have anything official from Toyota? If not, how do you know for sure if and when this design improvement was made? Thanks.