Car is just over 9 years old
Decided against replacing pre-cats 2 years ago on recommendation of Toyota specialist as car had done 80,000miles already and all the bolts looked as if they would disintegrate if I tried!
Using oil on an increasing basis but probably less than an Mazda RX-8 and I just check regularly and top-up every other weekend but cheaper than replacing engine!
Recent oil change wuth Mobil S and added 'Restore' as recommended by Quention Wilson but car still pinks when hot.
Cooling system has just started losing coolant somewhere so something else to top uo at the weekend!
A few other minor ailments (like myself) but a great car otherwise!
Oh this has to be a wind up? One of the symptoms of engine death is an cumalitive use of oil, and now you're saying your 100k engine is fine - asides from the increase of oil usuage......?
Why a wind-up? Most of my cars use oil, some more than others and oil costs a lot less than an engine replacement!
Some of us run cars on a budget and that's possibly why we bought a relaible Toyota in the first place!
My post was to paint a more positive picture about pre-cat's rather than the usual doom and gloom!
When I said about increasing oil consumption I'm not talking about litres per day!
Yet!!!!!
Quote from: "1000 PR"Using oil on an increasing basis but probably less than an Mazda RX-8 and I just check regularly and top-up every other weekend but cheaper than replacing engine!
That is your problem right there, consumption has increased, obviously something has changed.
Not exactly - it's been using oil for the last 5 years at least!
Surely just the oval engine bores becoming more oval?
Quote from: "1000 PR"Not exactly
Surely just the oval engine bores becoming more oval?
Which is a change then, meaning that soon your main cat will be clogged with oil and probably pre cat debris and your engine will die.
The advice you were given was flawed im afraid.
Which lets oil past which melts the precats...
Congrats on your blinkers, they fit really well! s:D :D s:D
It was probably too late to save the engine at 80,000 miles when I found out about the pre-cat issue!
Thanks for the doom and gloom to add to my day!
Quote from: "1000 PR"It was probably too late to save the engine at 80,000 miles when I found out about the pre-cat issue!
How can you be sure?
Thanks for the doom and gloom to add to my day!
Well your thread seemed to smugly say that you had 100,000 miles with no pre cat problems, when in reality..........
Quote from: "1000 PR"Thanks for the doom and gloom to add to my day!
Yes, Nelix and Dan_M are quite good at that s:wink: :wink: s:wink:
On the positive side, good to know that you can get to that milage on a 1ZZ. People forget that if an engine is using oil then what you need to do is top it up regularly, in the same way that you need to fill up with petrol s:D :D s:D . I had a Volvo 240 estate with 165k on the clock, did start to sound like a diesel though but hey.
Sorry Roger, im sure that engine is good for another 100,000 miles, Dan and i are just being silly.
Quote from: "roger"Quote from: "1000 PR"Thanks for the doom and gloom to add to my day!
Yes, Nelix and Dan_M are quite good at that s:wink: :wink: s:wink:
Because clearly Will didn't post in this thread either? Roger, if you're going to criticise people for stating the truth, you might want to at least keep some level of consistency. Or perhaps you would prefer a forum where we completely ignore the obvious?
I expected better from you.
Quote from: "Dan M"Quote from: "roger"Quote from: "1000 PR"Thanks for the doom and gloom to add to my day!
Yes, Nelix and Dan_M are quite good at that s:wink: :wink: s:wink:
Because clearly Will didn't post in this thread either? Roger, if you're going to criticise people for stating the truth, you might want to at least keep some level of consistency. Or perhaps you would prefer a forum where we completely ignore the obvious?
I expected better from you.
In my best Irish accent "Its the way you tell them"
For fucks sake you lot, there aren't many 100k cars that don't use oil. The solution is to check it regularly and top up regularly. Eventually as with everything, it will expire. This ongoing battle is getting boring - grow up.
100,000 is a good result you should be pleased,any mileage now is a bonus. s:bounce: :bounce: s:bounce:
Quote from: "1000 PR"My post was to paint a more positive picture about pre-cat's rather than the usual doom and gloom!
When I said about increasing oil consumption I'm not talking about litres per day!
Yet!!!!!
I agree with the "elder" members of the club in that the pre-cats should have come out as it is well documented what happens to your engine/cat etc if they fail, HOWEVER i can understand with the Op's point of view.
Granted he was misinformed about the pre cats by Toyota but what's his car worth in real terms ? 100k mileage, 9 years old, best part of not a lot really !£2000 ish maybe.What's a replacement engine and cat going to cost, £1500 fitted, therefore just keep topping up until it dies and sell it as a non runner for £800- £1000 and move on.
Hindsight is great, he choose to rely on someone else's "expertise" and took his chances,rightly or wrongly( maybe his engine would be in fine fettle now if he removed the pre cats,or at 100k past its best anyway) I don't think he was being smug or gloating, just stating his personal experiences.
Is it me or is it gettinga bit caustic on here if you are not a regular poster s:oops: :oops: s:oops:
I don't believe there is a precat problem, I believe its an oil control ring problem, after all that is the problem Toyota fixed, they haven't ever changed the design of the precats. If you get a pre 2003 engine to 100K you're doing well.
Quote from: "custardavenger"I don't believe there is a precat problem, I believe its an oil control ring problem, after all that is the problem Toyota fixed, they haven't ever changed the design of the precats. If you get a pre 2003 engine to 100K you're doing well.
I agree with you 100% on that Rob, why else would Toyota change the piston design in 2003.
Precats as a individual component do very little except to reduce your emission during cold start - good old yanks hey, so when they fail, it's either as a result of someone hitting them or taking a heavy knock or another component failing which in turn causes the precats to fall to pieces. Those people who decide to run and ignore this, run the risk of either total oil loss or bearing failure due to precat dust - you take your chance I say and good luck with your decision and if you do achieve over 100K good for you.
Another problem that people are facing is the previous owner history, cars are becoming more affordable but if the car as not been treated right - buyer beware.
Rob.
Quote from: "jonfy"Is it me or is it gettinga bit caustic on here if you are not a regular poster s:oops: :oops: s:oops:
s:lol: :lol: s:lol: On this forum? Nah!
Quote from: "1000 PR"Car is just over 9 years old
Decided against replacing pre-cats 2 years ago on recommendation of Toyota specialist as car had done 80,000miles already and all the bolts looked as if they would disintegrate if I tried!
That puts your car in the high risk bracket for engine failure.
Quote from: "1000 PR"Using oil on an increasing basis but probably less than an Mazda RX-8 and I just check regularly and top-up every other weekend but cheaper than replacing engine!
From what I can work out, the pre cats are a symptom of the oval bore problem. Oil consumption goes up and gets into the combustion process and into the exhaust system where it causes the pre cats to run very hot leading to them crumbling. The valve timing controlled EGR function then draws sharp bits of ceramic, coated in rock hard metal, into the cylinder bores which then results in very accelerated bore wear, and before you know it the engine is using enough oil to cause either oil starvation or problems running. If you take the pre cats out before they crumble, the oil loss will get worse over time, but your engine is significantly less likely to suffer catastrophic failure. Topping up the oil is cheaper than replacing the engine, so is removing the precats early.
Quote from: "1000 PR"Recent oil change wuth Mobil S and added 'Restore' as recommended by Quention Wilson but car still pinks when hot.
Cooling system has just started losing coolant somewhere so something else to top uo at the weekend!
The car is pinking when hot. This could be a result of low coolant level leading to the head overheating, or more likely given the oil consumption, the presence of oil in the combustion chambers causing detonation. What happens is that as the piston rings start to fail, or the bores get scored, the combustion pressure gets past the rings and pressurises the crank case. This leads to excessive oil mist being breathed into the inlet side of the engine. Once this gets to the cylinders, it compression ignites and you get pinking. Alternatively, the oil causes carbon deposits to build up in the head and on the piston crowns, this glows and ignites the fuel before the spark fires. So it could be you have really bad oval bores (oil consumption in the 1L/ 1000 miles area) or scored bores, or at best, a bit of oil consumption and low coolant. I am hoping it is just low coolant level. Either way, pinking needs to be sorted as it puts huge mechanical and thermal stress on the engine. IMO this is a safety issue as pinking can lead to an engine going pop.
For anyone else considering leaving precats in on a pre facelift car, consider that bores going oval seems to be quite sustainable if the precats are removed. If the car suffers oval bores and the precats are in, then you run a high risk of rapid and catastrophic engine failure.
Keeping me fingers crossed for you.
Chris
That's a really well structured analysis.
The other perspective is that the engine has done well to get to 100k so all you need to do now is to watch the oil. Obviously eventually it will die, but excessive oil consumption alone won't write off the engine. Depends upon what you want from the car. If it's the daily commute then just watch the oil, if you want to race it or track it then new engine now I guess. Check the plugs are right for the pinking issue and / or try upgrading the octane (won't get rid of the cause but may solve the problem).
Trouble with pinking caused by oil is that the oil droplets ignite before the spark fires, so no amount of octane increase (or the cars built in knock compensation) will prevent it. On the other hand, if it is carboned up, running a good premium fuel like Shell V power, with its high grade detergents, may clean the head and crowns up a bit. For the sake a few quid over two or three tankfuls it is worth a punt.
Chris
I have 109k and never used any oil
Quote from: "uktotty"I have 109k and never used any oil
Not up to that sort of mileage yet, but have always run on the best available oil and have never had a car that drank oil, even out past 170,000 miles.
Chris
Quote from: "sportscarjames"I have a face lift 2004 mr2 covered 40k no issues to date, having taken advice of both Silverstone Racing and Toyota Mech, the de cat proceedure is a total waste of time and money on a facelift model
They both however stated would recommend on a pre 2003, even if the Toyota chap was somewhat hesitant in actually recemmending as such
A straight answer at last, facelift cars leave the pre cat well alone unless you want to waste money for the sake of it?
Really? Please explain then why we have at least one member with precat/oval bore failure on a facelift model?
The correct statement is that facelift models are far less likely to suffer it, not that they are immune.
Quote from: "FGrob"Quote from: "custardavenger"I don't believe there is a precat problem, I believe its an oil control ring problem, after all that is the problem Toyota fixed, they haven't ever changed the design of the precats. If you get a pre 2003 engine to 100K you're doing well.
I agree with you 100% on that Rob, why else would Toyota change the piston design in 2003.
Precats as a individual component do very little except to reduce your emission during cold start - good old yanks hey, so when they fail, it's either as a result of someone hitting them or taking a heavy knock or another component failing which in turn causes the precats to fall to pieces. Those people who decide to run and ignore this, run the risk of either total oil loss or bearing failure due to precat dust - you take your chance I say and good luck with your decision and if you do achieve over 100K good for you.
Another problem that people are facing is the previous owner history, cars are becoming more affordable but if the car as not been treated right - buyer beware.
Rob.
With over 30 years workshop experience I like to think I know a little bit about the internal combustion engine and have to hold my hands up in agreeing with the above from day one of joining this wonderful forum many years ago.
I like to give advice when I can and have on many occasions acted on advice that has reaped benefits, unfortunately things have gone the other way sometimes, where it hasn't worked out according to plan - but at the end of the day that is all it is........
advice.
It will always be up to the individual which direction to take, the bias towards damning you to hell for keeping pre-cats in has always been prevalent here and the horror expressed by new members when reading about their ticking time bomb cars is an unfortunate prequel to their introduction.
Thank you to the OP for being proud of this achievement and giving some of us members confidence in our own beliefs without needing to berate positive reports.
I got 160,000 out of my pre-facelift. It drank oil at an alarming rate but I kept it topped up. No matter what the reason I was more than happy with the miles per £ spent. Head gasket went in the end. I never bothered checking the pre-cats and never failed an MOT on emissions (odd windscreen wiper though) so presume the main cat held out to the end. It never missed a beat till the day it died and I worked it pretty hard. Fantastic car, even with all these terrible design flaws that are supposed to be dealt with urgently or woe betide. Just my experience of "pre-cat failure". Note to OP though, check your radiator, it's probably in pieces by now.
I hated driving my MGF because I was so worried about K series head gasket failure; Unfortunately, I crashed it and wrote it off before it happened s:lol: :lol: s:lol:
Quote from: "Les"With over 30 years workshop experience I like to think I know a little bit about the steam engine
Fixed that for ya s;) ;) s;)
Quote from: "sportscarjames"I have a face lift 2004 mr2 covered 40k no issues to date, having taken advice of both Silverstone Racing and Toyota Mech, the de cat proceedure is a total waste of time and money on a facelift model
They both however stated would recommend on a pre 2003, even if the Toyota chap was somewhat hesitant in actually recemmending as such
A straight answer at last, facelift cars leave the pre cat well alone unless you want to waste money for the sake of it?
They are wrong - there do seem to be less pre cat failures on post 2003 cars following the changes to the engine but I have seen the pre cats breaking up on a 2003 car that had just had a new manifold. Dan's car I believe.
I admire your style, but with a pre facelift car you might be heading for the big engine crunch. I hope not, but as you, say, 100k sports car engine miles ain't bad.
This topic always brings about (understandably) loads of interest and yet the Club will not raise the matter with Toyota ? s:? :? s:?
The problem does not exist with Toyota!
They will give you a free engine for something which is not their fault but there is and never has been a precat issue.
Recalls are very expensive you know
Good point that because the issue which they replace the half engine for is the failed oil ring / oval bore thing which is for up to 7 year old cars with a full Toyota service history consuming more than a litre of oil in less than 1000 miles. Precat's what the fuck are precat's s:D :D s:D
Quote from: "1000 PR"Decided against replacing pre-cats 2 years ago on recommendation of Toyota specialist as car had done 80,000miles already and all the bolts looked as if they would disintegrate if I tried!
Using oil on an increasing basis but probably less than an Mazda RX-8 and I just check regularly and top-up every other weekend but cheaper than replacing engine!
I think it's strange that you are suprised of the response of fellow forum members to be honest. The toyota specialist has given you wrong advice and I'm not sure of the reasons for his/her advice. If it's purely down to getting the studs out then they will have to come out when you replace the engine, the oil burning will continue after the pre cats are removed so the replacement engine will be on top of the oil. As for the comparison with a mazda, they may not have pre cats so the issue is not critical as with the MR2 roadster.
Above all, your statement may sway others who are considering taking out pre cats to keep theirs in only to have engine failure in the future. There is enough evidence on here to show this is a problem and so far you have been lucky but you must realise that the engine could go at any time with no warning, it only takes one small fragment and game over for your engine. Sandmanmr2 has an 06 mr2 which had signs of pre cat breakdown at very low miles.
If you're concerned about the manifold studs why not try the Diddy method (may not be the choice of methods but it worked for him) by removing the O2 sensors and the cat and knock the pre cats out in situ.
Go and bury your head in the sand if you want but dont have a go at forum members who are only trying to save you heartache and further expense.
Whilst I completely agree with the rest of the above post, I don't think the OP was in any way having a go at any forum members - the only comment that could possibly be taken that way was the lighthearted sentence "Thanks for the doom and gloom to add to my day!".
The rest of this thread has just been other existing members in agreement with each other mixed in with just a little bit of the usual political biccering midway s:lol: :lol: s:lol:
Quote from: "sportscarjames"A straight answer at last, facelift cars leave the pre cat well alone unless you want to waste money for the sake of it?
It cost me about £30 for the gaskets, £5 for some exhaust bolts and about a day of graft. I think that's damn good insurance against pre-cat failure even if there is only a one in a million chance of it happening s:D :D s:D "Waste money for the sake of it", oh no, it's call risk management!
No wonder marketing and advertising work so well, we all just bite so easily s:lol: :lol: s:lol: .
I think that with a standard facelift car, I would (did) not bother taking out the precats but did replace the lot with a PPE setup. The evidence points to precat failure usually being down to excessive oil use. As for Toyota not recognising it as a precat problem, that is because they have the same issue of excessive oil use on other cars using the same engine, where precats are not fitted.
However, oval bores caused by blocked oil control ring returns are not the only possible cause of precat degradation. A misfire will quickly overheat the precats, as will anything else that leads to too much combustible material in the exhaust side (overfilling, very poor quality oil shearing down and burning off, dribbly injector, marginal o2 sensor or MAF etc.) Then there is engine wear, has the engine been abused from cold, fed on cheapo oil, had a poor quality filter fitted, missed a drain interval, suffered from fuel dilution issues due to only being used for short runs?
If you are mapping, running too rich could cause problems as well. Potentially, because they are ceramic and relatively brittle, alterations in vibration modes could cause problems too. If you run too much advance, this could cause knock and change the vibration modes (I have seen this kill several gearboxes before it was figured out) or an aftermarket exhaust could potentially change the way the manifold resonates (though it is unlikely because of the flex couplings, a change in return pulse form could cause issues).
At the end of the day, for a pre facelift car, it is a no brainer. To go hand in hand with this, I would also advise using a high detergency fully synthetic oil from new to help keep those oil control ring lands clear. For a post facelift car, the probability of a failure are much lower if it is running properly. It is down to the individual to decide, maybe when the miles or oil use start to climb would be a good time? Or just whip 'em out for peace of mind anyway.
Chris
Just reading the June 'Car Mechanics' mag (the one with the roadster service shedule in it, thanks Roger) and page 81 lists an 'Engine Restorer and Lubricant ' product basically designed for high miles engines. Obviously take it with a pinch of salt but basically I think these sorts of additives are thick goo temerature resistant substances which will help reduce oil consumption, particularly in conjunction with a thicker oil. I used STP, a similar sort of product, many years ago to good effect.
Again, only if it's the daily commute and you don't want to rev the nuts off of it s:D :D s:D
m http://www.AmericanTechnology.co.uk (http://www.americantechnology.co.uk) m