Precat removal - How I did it...

[Anonymous]

Toyota do recommend a cat check after the new block etc is fitted. Done electronically by means of a waveform scan of pre and post cat oxy sensors.

Sounds like a lot of work for something that's easier if you just undo a couple of bolts and look at it with your eyes...

[leon_in_uk]

yea but you have to take the manifold off completely to inspect the whole pre cat honeycomb!!

the oil light did not come on
nor did the engine light
i serviced the car 2 months before the damage

i didnt check the oil for 2 weeks and when i heard the diesel sound the dipstick was bone dry, so it did burn the oil...

[Anonymous]

Its hard to know what happened first aint it. Cat or oil loss?
I have seen first hand the worn/damaged pistons. (quite a few of em........) they DO show signs of the piston skirt being overheated, the oil control ring totally gummed up, and drain holes very much blocked. There has been no evidence of any wear and tear by any coarse particles such as a powdered cat.

The bore wear is often excessive, but generally smooth, not scored etc.
The only instances Ive seen where the pistons are scored appears to be carbon smeared up the side of the piston from the oil control ring area.

I cant believe there seem so many of you guys with problematic cats, when we havent seen any (honestly), not a one.

[Anonymous]

Toyota do recommend a cat check after the new block etc is fitted. Done electronically by means of a waveform scan of pre and post cat oxy sensors.

Sounds like a lot of work for something that's easier if you just undo a couple of bolts and look at it with your eyes...

The matrix may also be intact still, but not performing efficiently due to the oil damage. Always safer to check the efficiency electronically.

[Anonymous]

Ill try to find out.....

Thanks for the info.  You seem to be saying that the modified pistons have never been fitted in production?

If this fault occurs, go see a dealer. Yes really. Even if outside the warranty age/miles, it'll be worth the trip..............................

I presume that a full Toyota service history is required, though?

[Anonymous]

Its really interesting to hear your comment Rollazuki - I had my precats taken out just after my MOT in Feb and they had just started to degrade - however i've had high oil consumption prior to that ever since owning the car - i'm getting around 1L to 600 miles at the moment (the car has done 43K and is a 51 plate) and as you mention i dont see a single puff of smoke out of the exhaust.

I'm pretty sure my symptoms would have caused the precats to break up further had i not had them removed.

I'm topping up the car on a weekly basis at the moment and apart from that it runs great. I'm assuming though if i continue i will knacker my main cat? -  I'm probably going to get it looked at in the Winter when i'll use it a lot less - is it possible to clean up the existing pistons and replace rings etc or will it require a new shortblock to the new design?

[Anonymous]

i'm no legal buff, but if this is all true (and we have no reason to believe otherwise), then Toyota are selling an engine that has a design fault which will cause it to fail after xx,000 miles; surely they could be got on fit for purpose or something??

I mean, it must be perfectly reasonable these days to expect a brand new car to last at least 5/6yrs or 100,000 miles??   s:evil: :evil: s:evil:    s:? :? s:?    s:roll: :roll: s:roll:

[Anonymous]

i'm no legal buff, but if this is all true (and we have no reason to believe otherwise), then Toyota are selling an engine that has a design fault which will cause it to fail after xx,000 miles; surely they could be got on fit for purpose or something??

I mean, it must be perfectly reasonable these days to expect a brand new car to last at least 5/6yrs or 100,000 miles??   s:evil: :evil: s:evil:    s:? :? s:?    s:roll: :roll: s:roll:

I suggested this once before (after the death of my first roadster from precat failure, when toyota mucked me about) and I actually sent a comprehensive email to watchdog, but never got any response. The trouble I had at the time was that nobody really seemed to care   s:( s:(  

I was just lucky that this forum existed and I knew the real problem with the car which allowed me to get my money back from the dealer.

Richie.

[heathstimpson]

Theres now a modified short block assembly(and piston/ring set) to cure this.

Do you know exactly when Toyota started to supply modified engines  s:?: :?: s:?:

[Anonymous]

I checked all bulletins from TGB this morning and found non, I also checked product reports from dealers and found non.

Ignorance is not proof. Absence of proof is not proof. Come check across the pond and gaze in wide-eyed wonder at dozens of documented cases of pre-cats failure.
 m http://www.spyderchat.com/phpBB2/viewtopic.php?t=46 m

There may be other forces involved causing  the pre-cat matrix to break up but that will kill the engine.

Factory Revisions

06/2001 New S-belt Tensioner
11/2001 New Piston Rings & harmonic balancer
12/2001 New pistons
02/2002 New Longblock
04/2002 New oil pickup
06/2002 New Oil pump
07/2002 New Water pump
10/2002 New Cams.

At some point, probably in 2002, Toyota started using different engine designations such as 1ZZW75 instead of 1ZZ-FE. Its on a sticker on the block by the S-belt. Its my personal experience that a catless 1ZZW75 is a good engine.

[kire612002]

At some point, probably in 2002, Toyota started using different engine designations such as 1ZZW75 instead of 1ZZ-FE. Its on a sticker on the block by the S-belt.

My sticker  says 1ZZW52Q??

[red_leicester]

i'm no legal buff, but if this is all true (and we have no reason to believe otherwise), then Toyota are selling an engine that has a design fault which will cause it to fail after xx,000 miles; surely they could be got on fit for purpose or something??

I mean, it must be perfectly reasonable these days to expect a brand new car to last at least 5/6yrs or 100,000 miles??   s:evil: :evil: s:evil:    s:? :? s:?    s:roll: :roll: s:roll:

The problem is that, as Rollazuki mentioned, it only affects a small % of cars, so it's not an inherent design problem with the car.

Also, Toyota would argue that the car was designed to be "fit for purpose" and these problems were unforeseen.

Surely if every car that (let's say) 2% of which had a problem that required it to returned to the dealer for repairs after, say, 60000 miles, was taken off the road the streets would be very quiet.

[Anonymous]

At some point, probably in 2002, Toyota started using different engine designations such as 1ZZW75 instead of 1ZZ-FE. Its on a sticker on the block by the S-belt.

My sticker  says 1ZZW52Q??

What year is your car and is that a dealer swapped engine?

Mines a 2000 with a 2002 1ZZ.

I'm sure the designations have meaning  - if only someone had a list.

Starting a poll over on SC. Please visit and post up.
 m http://www.spyderchat.com/phpBB2/viewtopic.php?t=32515 m

[kire612002]

What year is your car and is that a dealer swapped engine?

02 license but according to its serial number it was manifactured   oct 01.
i bought it 6 months earlier so cant be sure although  its service history book doesnt show any engine swapping.

[Anonymous]

At some point, probably in 2002, Toyota started using different engine designations such as 1ZZW75 instead of 1ZZ-FE. Its on a sticker on the block by the S-belt.

My sticker  says 1ZZW52Q??

... and mine says 1ZZW52EQ (2005 car).

[Anonymous]

Like I said, re older cars.....contact a dealer...............cant say no more..........

[kanujunkie]

Its hard to know what happened first aint it. Cat or oil loss?
I have seen first hand the worn/damaged pistons. (quite a few of em........) they DO show signs of the piston skirt being overheated, the oil control ring totally gummed up, and drain holes very much blocked. There has been no evidence of any wear and tear by any coarse particles such as a powdered cat.

The bore wear is often excessive, but generally smooth, not scored etc.
The only instances Ive seen where the pistons are scored appears to be carbon smeared up the side of the piston from the oil control ring area.

I cant believe there seem so many of you guys with problematic cats, when we havent seen any (honestly), not a one.

you sound like a toyota employee who has a lot of experience, but to be honest that does not mean that you can guarantee to me that what you say is the case. By the sounds of it your looking for particles you can see with the naked eye. Were talking about microscopic particles that are invisible to the naked eye and only a laboritory test would answer that. without a test case to test under laboritory conditions you cant really say. Why also has every case weve seen, the precats have dissapeared and crumbled onto the main cat? Personally i think that thats the trigger and the load put upon the engine overworks it and that destroys the oil control side of the engine.

[Anonymous]

Why also has every case weve seen, the precats have dissapeared and crumbled onto the main cat? Personally i think that thats the trigger and the load put upon the engine overworks it and that destroys the oil control side of the engine.

Thats not strictly true, Stu. In mines, my precats were gutted (whilst still totally intact i should add) and my engine failed not long after (unrelated to the precat gutting I should also add)  due to excessive oil consumption drying out the big end. A stripdown of the old engine and measurement with a micrometer diagnosed that the bores were excessively worn, with no visible signs of scoring (but as you mention above its not always possible to detect without lab conditions)

I still think that one cause is that the excessive amounts of oil consumed eats the Precats and this is what causes them to break up thus worsening the problem by blocking the main cat. (probably closest to toyota's stance too)

I agree with everything else you've said above though, and lets face it, theres probably other things out there that cause the precats to fall apart (one explanation was resonance i believe?) and cause the "Typical" precat failure mosts owners experience.

but in most instances, it is impossible to say whether the oil consumption or cat failue is the mitigating factor seeing as one causes the other with these failures.

At least you can immunize against the possibility of one of these failures by removing the precats and help prevent the other with regular oil changes using premium oils.

Richie.

[Anonymous]

Thats not strictly true, Stu. In mines, my precats were gutted (whilst still totally intact i should add) and my engine failed not long after (unrelated to the precat gutting I should also add)  due to excessive oil consumption drying out the big end. A stripdown of the old engine and measurement with a micrometer diagnosed that the bores were excessively worn, with no visible signs of scoring (but as you mention above its not always possible to detect without lab conditions)

I still think that one cause is that the excessive amounts of oil consumed eats the Precats and this is what causes them to break up thus worsening the problem by blocking the main cat. (probably closest to toyota's stance too)

Was your car 100% healthy before you removed the pre-cats?

[Anonymous]

Was your car 100% healthy before you removed the pre-cats?

over the first 2 months (and 1500 miles), my car used no oil whatsoever.

I then had it serviced (when returned to me, the Oil level was well above "High") and over the remaining 4 months / 3500 miles, I used about 2l to keep it topped up in the middle of the scale. During this time, the oil never went below "Low" and i never filled it near "High"

The oil loss on my car was very quick and dramatic, ie my oil level was fine the morning the engine died, but about 70 miles on the clock later that day, the knocking developed and it took 2.5l of oil to being it back onto scale.

My engine showed no symptoms prior to this and even when it developed its knocking noise had no loss of power whatsoever.

(And yes, all precat was removed form my manifold - by visual inspection* then a high pressure flush)

How come?

*Within all possible limitations

[Anonymous]

I may have this completely wrong, but 2L of oil in 3500 miles?? and that was before you started experiencing issues??   s:shock: :shock: s:shock:  

I'd have said that 1/2 a litre of oil every 800 miles or so was definately an issue, even if you weren't noticing any power loss or noises...?   s:? :? s:?

[filcee]

I'd have said that 1/2 a litre of oil every 800 miles or so was definately an issue

Page 165 of your owners manual says that it is normal to consume oil, quoting a maximum consumption of 1.0l per 1,000 km or 600 miles.

I think our last Seat said this in the manual too, and I wouldn't mind betting that the manual for the current Seat says the same thing.

Now, it's up to you to decide whether this number is 'normal' for an engine, or has been researched and measured by experimentation by Toyota (or Seat for that matter), or whether it's simply 'a statement' that is there to protect the manufacturer in the event of a claim from a customer.

By this measure, your stated consumption is 'normal'.  However, this sort of consumption:

70 miles on the clock later that day, the knocking developed and it took 2.5l of oil to being it back onto scale

is well outside of that quoted in the manual (approx. 21 litres per 600 miles  s:shock: :shock: s:shock: ), so I don't think it's unreasonable to assume you would have some grounds for speaking to Toyota about the problem.

Please note, usual disclaimers apply: I am not a lawyer, your mileage may vary etc. etc.

[Anonymous]

I agree with you james that it was a lot of oil to use, but was within specs and because I was checking the level once a week i never really thought about how much I'd had to put in until the engine failed and i had to take it into consideration.

However as stated for me to lose all of that oil over 70 miles that day was totally extreme so perhaps something just gave way as the first thing i knew about it was the knocking sound. The oil pressure light never even flickered once!

Luckily toyota honoured me in this instance and replaced the shortblock under warranty, so now I have a perfect engine again   s:D s:D  At the time of the repair, the car was just over 5 years old so I suppose I can't complain seeing as it was well out of warranty, my only gripe is that on my first roadster when it died of an actual precat failure toyota didn't want to know - at least their attitudes have changed (either that or helensburgh toyota is much better than arnold clark linwood toyota!)

Richie.

[Anonymous]

I know it's been a while since the last post, but I if you are going to do this then please bear in mind that catalytic converters contain platinum (or palladium). Platinum in your lungs is not a good thing, so wear a mask.  s:shock: :shock: s:shock:  

FYI- durability testing for the EU is (or used to be) 100,000 km simulated on a bench engine using an accelerated aging cycle. Typically, the engine speed, exhaust temperature and load are varied to condense a lifetime of use into 100 hours- it does not simulate "real world" driving conditions, and especially not the vibration experienced by close coupled catalysts- this is tested using a hot vibration test. I am convinced the catalyst break-up issue can be traced back to a faulty batch of catalyst substrates (the honeycomb bit) because there is no way they would have used this design if the catalyst substrates had broken up in the test.

[Anonymous]

That's a huge batch of pre-cats Toyota bought then, considering we've seen them 'disappear' on model years '99-'03  s:wink: :wink: s:wink: