Cracks in my timing chain cover-why?

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Cleaning up the timing chain cover for reassembly of my 1FZ. Noticed some cracks on the power steering gear side, and a single crack on the opposite side, in the oil pump chamber. I am resigned to buying a new one but what the heck caused this? This is in a '96 LX450 with 280k. (Or did I just answer my own question, 280,000 miles...).
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Toyota used all the parts that failed QC in the lx450's because they knew nobody would take their Lexus offroad.......
 

COYS

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Normal. I had two new ones in my possession and noticed the same.

I’d personally replace with new regardless since it comes with the oil pump screw looking thing and cover as one unit iirc.

If for any reason you need to get this cover off again it’s another head off job. No thanks.
 
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In the steering pump side, you guys are probably right. That does look like a lot of images on the google search. But the other side (oil pump chamber), running just above the bypass hole, do you see that hairline crack. Follow it across to the left, I'm pretty sure that's a crack. I'll pull the bolt and get a better picture right now!
 
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First picture is the area we are talking about, next two are what I'm concerned about...I ran a Sharpie over it and wiped it off. The ink stayed in the area I think is cracked. I was less concerned about this crack than the stuff I now realize is casting...Drive on or replace?
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^ The Dremel grinding will create stress zones and it'll crack there.


j/k
cheers,
george.
 

Bambusiero

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Those are casting marks they aren't cracks in my opinion I don't think I would replace it. Was it leaking? What does the other side look like?
Agreed. Have seen the same on water pump housing - casting mold shrinkage - no concern.
And this is a machining dig/scratch - not a crack - it's an even, smooth curve. A crack would follow a random grain boundary shape.
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They are one and the same. Aisin is a Toyota Group subsidiary and Aisin manufactures the cover for use on Toyota vehicles.
Please correct me but wouldn't Aisin aftermarket parts have more discretion (tolerance/qc wise) than timing covers made specifically for Toyota?
 

PIP

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It is the nature of die cast aluminum parts. That is what they look like. Nothing wrong with your timing cover that I can see.

From producing automotive parts and products for nearly 2 decades I can tell you that there is a difference in the parts that are produced to build a new vehicle VS the parts that go into a box for repair parts, regardless of who's name is on the box or the part.

Parts that go into the build of a new vehicle are delivered under strict performance criteria. Basically, if a wheel bearing or a glove box latch fails in a new vehicle the manufacturer is responsible to make the vehicle manufacturer whole. That means paying for parts and labor to replace every single failed part out there.

Parts made for stock to repair existing vehicles carry no such performance clause.
 

COYS

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I was curious and compared what I paid back in 10/2021 for 11310-66020 = ~$250 for a Toyota badged part. Today's price = $319.

Cheapest now is the Aisin version from Rockauto at $282 delivered. I think it's still completely reasonable for such an important part you do not want to question/mulligan.

Gl!
 
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It would probably have worked, but if it leaked🌋 that cost of a new one would feel like a bargain. So I ordered a new one from Partsouq. Other parts too.

By the way, I started looking at the other AL pieces for cracks and decided to quit looking so close. Thanks for the replies
 
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I was curious and compared what I paid back in 10/2021 for 11310-66020 = ~$250 for a Toyota badged part. Today's price = $319.

Cheapest now is the Aisin version from Rockauto at $282 delivered. I think it's still completely reasonable for such an important part you do not want to question/mulligan.

Gl!
Prices are only a little higher. Suprising considering everything else
 

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