10K oil changes are BAD! ??

Off Topic....

Thanks for the link.
I have now joined the EGR Delete Club this morning!
I'm at 153k miles. I know I should clean the EGR system someday....
And the way I drive I never have two tank fulls the same MPG. It might be hard for me to quantify any difference.

 

Doesn't that discredit the theory that a clogged EGR system will fail a headgasket?

 

I could come up with some reasons, but I think your mind’s made up.

 

No one has 100% found the exact reason. I personally believe it is a combination of things.
And at times, certain things. And it seems those who do mostly city driving have issues
sooner and more often than those who do mostly highway driving. And also HOW it's driven.

 

It's just the opposite.
It's implying that without an EGR system to get clogged in the first place, Prii in Brazil do not routinely have a head gasket go bad.
Of course this is Hearsay without actual data to back that statement up.
Only the Brazilian Toyota mothership knows what the Toyota dealerships report in the way of repairing head gasket failures.
Of course, just like here, Toyota doesn't know the extent of HG failures because a lot of the repairs take place in independent repair shops.

 

I found it interesting that the water pump impeller on your high mileage car was in good shape whereas other folks are saying theirs were badly deteriorated at much lesser mileage. That tells me they haven't been changing the coolant at the prescribed intervals or used inferior coolant. I think poor maintenance practices contribute to the headgasket life. Corrosive coolant is going to eat the headgasket and water pump and raise operating temperatures and cause overheating. Of course driving practices contribute as well.

 

of course, the maintenance schedule has quite a long interval for coolant changes, and no rec for testing.
dealers aren't helping ether, and toyota europe claims it is because of faulty waterpump speed software.

 

90% of my driving is highway. So they engine temperature is more steady.
With city driving, it changes. So that's likely part of the reason it fails, it's plastic...

 

Seems like a strange reason for an electric water pump with a plastic impeller to fail.
Its duty cycle is always changing RPM. I'm hoping the latest and greatest SW update addresses the duty cycle to help with the head gasket at high speed/power duties.

Do you recommend changing the entire pump assembly at X miles, preventatively? Can the impeller be changed separately?

 

Apparently. Of late there’s been a lot of impeller-only offerings. There’s a thread here with some discussion.