A quick question - buying a 2!

Anonymous · January 28, 2007, 09:26

Hi Guys,

I'm off to look at a 2 today that's for sale privately.

It's one owner on 51 plate with 50k on the clock. However the engine was replaced @ 35k. Is this a good or a bad thing??

Personally I think it's a good thing! A newer engine in an older car, plus there is less chance that the pre-cats have been damaged!!

Cheers,

Anonymous · January 28, 2007, 09:31

Good thing if everything was replaced properly (especially the main cat, which is a must), but a bad thing if it wasn't. I'd still say the usual checks apply, plus keep an ear open for anything sounding unusual from the engine or really obvious flat spots from about 3K rpm onwards.

*EDIT* That is, of course, if the pre-cats were the reason for the engine being replaced in the first place.

Anonymous · January 28, 2007, 11:12

I was at Silverstone Performance last week with Roger talking about pre cat failure, and Mark (owner of sp) said his opinion was that it was the engine that knackers the pre cats not the other way round, when will there be a definitive answer s:? :? s:?

or was I day dreaming !!

kanujunkie · January 28, 2007, 12:06

never been confirmed either way, personally i beleive its the engine oil control rings that fail and the resulting oil thats passed onto the precats causes them to degredate and collapse onto the main cat.

but equally there are a lot of people who beleive that the cats degrade and throw particles back into the engine, these particles then wear the piston rings and cause them to go oval

floors in both theories and hence why mr.T seems reluctant to discuss it further

Anonymous · January 28, 2007, 12:09

always thought engine fail first, cat second, but we could argue this all day and never have a definative answer

heathstimpson · January 28, 2007, 20:26

My guess would be engine goes first putting oil into precats s:? :? s:?

Anonymous · January 28, 2007, 21:51

I also agree (IMO) that its the oil control rings that fail, which then causes bore wear. This then causes the oil usage that destroys the precats.

Why?

Because even after de-precatting my car it started to use oil heavily and required a new engine (under warranty at the time, of course). Upon stripdown of my old engine I was told that it was oil control ring failure and bore wear (measured with a micrometer) however the bores were still "Tubular"

I believe that if i hadn't de-precatted the oil use would have caused the precats to be broken up and block the cat. It would be entirely possible for some particles to get sucked back into the engine during EGR and the problem would just exacerbate. This (imo) is what had happend to my first roadster.

Im not quite sure about the whole oval-bores theory though, until i've seen it in the real that is?!?

Richie.

Anonymous · February 7, 2007, 10:49

As a new owner I'm interested in this issue.
Richie's post would suggest that removing the pre-cat is not necessary if that is not the primary cause of engine failure.
Before I make up my mind I would like more information about (a) how common these failures are and (b) how the engines actually fail.
Do these engines suddenly sieze (which would support the cat break-up theory) or do they need replacement because they start to use excessive oil? Excess oil consumption would eventually block the cat which would cause severe loss of power, but wouldn't cause engine seizure.
Visual examination of any failed engine should reveal the cause of the failure, so more information along these lines would be much appreciated.
Mr. Toyota must know the answer!

markiii · February 7, 2007, 10:52

seeing as how we've discussed this to death in teh past and tehre is a very comprehensive sticky in teh maintenance forum.

please do a search and have a read before asking that we recite war in peace again s:wink: :wink: s:wink:

Anonymous · February 7, 2007, 11:20

Markii
Oops, sorry! Point taken.
I have read the excellent thread to which you refer, but it still doesn't answer all my questions. Does anybody know precisely how common these engine failures are, and when engines have failed how often has the cause of failure been firmly established?

markiii · February 7, 2007, 11:26

chicken and egg,

some people will argue, rings, some precats, noe one has ever proved either and Toyota barely acknowledge teh problem let alone teh cause.

failre rates are impossioble to count as for every one who posts on here there are probably 10 owners who don't.

muffdan · February 7, 2007, 12:13

Having had two pre-cat failures and two replacement engines I can definitly confirm that it's not something you want to take a risk with. First failure happened after 55k, second failure at 75k.

Markiii is right that there is debate over whether the pre-cats are the cause of engine failure, or a result of engine failure, but with my second failure this is a list of events:

- my car used about 1litre of oil every 1500 miles
- pre-cat falls apart and blocks main cat causing power loss, resulting in a 20 mile drive to Mr T. (2 miles from the garage the engine developes a rattle).
- Once the car is back from Mr T oil consupmtion is 1 litre every 250 miles.
- 1500 miles later, engine was smoking continuously and the engine is replaced.

My increased oil consumption was a definite result of the pre-cats failing. Possibly there was something amiss with the engine that caused the pre-cats to fail, but there is no mistake that the broken up pre-cat material caused significant unrepairable damage to my engine.

My point is that should you develop a relatively minor problem that causes your pre-cats to break up, then they will in turn destroy your engine.

Its better safe than sorry, I learnt it the hard way.

Anonymous · February 7, 2007, 12:47

i have noticed on spyderchat some owners have had multipal engine failures, is this down to bad luck or driving style- not warming the engine before flooring the pedal.

roger · February 7, 2007, 13:27

Quote from: "mick"i have noticed on spyderchat some owners have had multipal engine failures, is this down to bad luck or driving style- not warming the engine before flooring the pedal.

Or a bad repair!

If the failures were anything to do with pre-cats, I did read on there that some (if not all states) have a long / lifetime warranty requirement for emission parts. May be the cats go, get a repair, cats go again, another repair etc etc.

Again, wherther its bad cats, bad engines, bad driving, who knows for certain!