NEW!!! Service Bulletin for Engine Knocking at Startup T-SB 0012-10

Assuming you're somewhere in either the GTA or Ottawa area I'm curious which mechanic you're using.

 

Ok, so you want me to call him back and say, "some dude on the internet just said I'm making a mistake, and you (the mechanic, who inspected my car and did a whole assessment on the condition of the vehicle), is wrong, so do this instead"?

Automotive Edge on Victoria St. in Kitchener:

Auto Repair & Mechanic Shop Kitchener, ON - Automotive Edge

 

Not "some dude"? I ain't not cowboy. But others have told you also.
And it's common sense. The timing chain has NOTHING to do with the head gasket failure.
Nothing. Timing chains on Toyotas last a long time.

The water pump does have something to do with the head gasket failing.
95% of the people on Prius Chat will tell you.

Your mechanic is wrong. If you want to replace it, go for it. But be smart, have him install
a new water pump. Or just replace the empeller. I am not the only one saying you should
replace the water pump.

And you should look for a technician, not a machanic. Because he will tell you also to
replace the collant pump.

What's the point of getting on Prius Chat, saying you don't know about something, getting
answers, then ignoring the answers, from people who have gone through the experience?

But as I said before, it's your car.

 

There is a Toyota recommended test of the timing chain which has to come off regardless during a head gasket job.



However they rarely stretch enough to be a problem. Some mechanics are used to rubber timing belts which have to be changed on an interval.

Replacing the Timing Chain Tensioner is recommended and properly sealing the Timing Chain cover to prevent leaks is essential. There are horizontal seams between block assemblies that need extra sealant. Many leak oil before or after. A dealer gets $1200 just to fix the leak.


With that said, I would verify the chain length and buy a tensioner and primary water pump first. Many reuse those parts and have no problems. The water pump also comes off in a hg job and can be inspected.

 

Thanks for the feedback.

I called and talked to the person again (I'm sorry, mechanic/technician, not sure of the correct terminology. No disrespect intended).

When I strongly suggested again that I'd like the pump replaced they indicated they were suggesting I just wait at the moment until they physically remove it to inspect it - and then make the decision at that time. I agreed and will wait.

Timing chain seemed like a no brainer for me and made total sense to do it - with nearly 400k km on it it is very likely stretched (I replace my bike chains twice a year no matter what, whenever I change my tires). Cheap insurance.

 

I'd say replace water pump* (and thermostat), and just check chain condition (post 1324 has info), go from there.

Are they replacing head bolts? Not strictly necessary, but most do, just safer. There are repair manual checks for that as well, but...

Toyota gasket kit (including head gasket) and head bolt part no's in attached. The gasket kit has most of the internal, pliable gaskets and seals, including the valve stem seals.

* They tend to fail around 150k miles

BTW, full engine section from Repair Manual is last link in my signature; might help your shop. (on a phone turn it landscape to see signatures)

 

(I replace my bike chains twice a year no matter what, whenever I change my tires).

A bicycle chain does not ride in oil! You should oil it often.
Do you have stock in a chain manufacture?

 

Just to go along with what @ASRDogman is saying, I would be suspect of the shop if they are making a big deal about the timing chain but not the water pump. Just google search "Prius water pump replacement" vs "Prius timing chain replacement" and you can see that the water pump is definitely a much more common issue, especially at your mileage if it hasn't been replaced before. Now that being said, everything is coming off for the head gasket anyway so the chain would be easy enough to replace, but not necessary if the original chain is within spec.

 

It does seem odd, for the shop to recommend chain replacement prior to even seeing it.

reminds of the time a prospective plumber was telling me a 40+ foot run of pipe would not cause us to use more hot water.

 

Why is there no class action lawsuit on this?
Toyota obviously sold a bum engine design.

 

This particular thread, every so often, needs a reminder that it's about a TSB that was issued very early in gen 3 about a kind of weird thing that can happen when a little water condenses in the EGR passages during a cold soak after a short run of the engine, causing a one-off rough start the next time.

Weird and scary when it happens, yes. Class-action lawsuit and bum engine design comments are probably being carried over from other issues with the gen 3 engine, discussed in other threads.

 

I just bought my 2010 level IV. My car is out of warrenty. Will the oil catch can do the same as the new oil catch manifold?

 

The oil catch can will reduce the amount of oil going into your manifold. The updated manifold is to reduce start up misfire caused by condensation that happened in the original manifolds.

 

Are there any photos around showing the two different designs?

I'm having a difficult time visualizing what kind of shape alteration could be made to mitigate this.

 

It did not work.

 

Visual Differences between updated Intake Manifold | PriusChat

This thread has a bunch of comments and pictures but from what I can tell there's not really any difference noticeable difference just looking at them.

 

I saw a fuzzy pic one time, in one Toyota's sales blurbs I think, a cut-away of the revised intake manifold. Sketchy take-away:

The original intake manifold brings exhaust gas into the intake manifold via a largish, transverse, full-width-of-intake-manifold passage, with four small passages branching directly off, one per engine intake port.

The revised intake manifold brings exhaust gas into the intake manifold via a largish, transverse, much shorter passage, which branches into two intermediate passages, which each branch into two small passages, one per engine intake port.

Short version:

Original intake is one-into-four. Revised intake is one-into-two-into-four.

The revision did not seem to help, at least in reducing head gasket failures. The onerous work-around: just clean it all out every 50k miles.

 

... which, in any case, wasn't what this revision was striving for. It was aiming to make the passages a little harder to snort condensed water out of at the moment the engine starts.

It doesn't seem to have been a slam dunk for that either; the best workaround for that issue still seems to be to avoid really short trips (like repositioning in the driveway) where the engine doesn't nearly warm up.

 

I found I can reliably spoof the car to allow EV when cold, by plugging in the block heater for at least an hour. Good for getting the car from garage to driveway, or out to the street.