Precat removal - How I did it...

catkins · September 3, 2010, 13:29

Cheers guys. I'm hoping this is going to make more sense to my other half than me (he is the one doing it, I will be observing and offering help where required because I'm no car expert! lol!)

Turbotrucker · May 15, 2011, 18:03

I changed an o2 sensor yesterday after engine management threw up a p0135. I noticed my pre cats are still in and thankfully intact.
I have a 52 plate on 86k, My engine never Ever misses a beat. Its run on Magnatec, rarely needs top up.
However I have ordered a new manifold now and it will be on next weekend:)
Just posting this to show that not all engines with pre cats still in are doomed. I have taken all advice and opinions from threads relating to pre cats, and have always been a little worried about my car regarding this. Gladly I have never experienced any problems of that nature;)

markiii · May 15, 2011, 23:33

Bet you didn't check from the bottom though

Ps magnetic is awful stuff

Turbotrucker · May 22, 2011, 18:24

I didn't feel the need to check the bottom. I'd always 'assumed' my pre cats weren't there, as soon as I confirmed they were still in, I ordered the manifold to replace it s;)

s;)
I'll let you know what the condition of the pre cats are this week once its been swapped:)

Anonymous · May 25, 2011, 13:22

Hi,

Im sure this has been answered before somewhere so sorry for the repeat but I'm planning a pre car gutting session this weekend and wondered if i will need a new manifold gasket? If so, i better get it ordered now before i start the job and cant finish it!

Thanks

Mike.

Anonymous · May 25, 2011, 13:46

if you plan on doing it i would at least get the two crush gaskets on the bottom as they dont like to be reused that much.

rodenal · June 5, 2011, 17:08

Done mine today, took me about 3 hours all in. Couldn't get the gaskets from Toyota for over a week so reused the existing plus some paste. All my exhaust bolts were manageable, had soaked then in penetrating fluid for the last couple of days. Lambdas came out fine too. Had real issues with the heatshield bolts now need replacements but my wallet won't be too worried about that

The precats were still in excellent condition on my 96k 2001. Oddly though the car appears to have had a replaceent engine or at least a replacement block as it had some markings on it like you see with scrapyard / rebuilt stuff. No idea why precats weren't removed as part of this but there you go they are now! Took a fair bit of effort to get then out of the manifold too which suprised me

Proof below! The stones were acquired after gutting BTW lol

motojoe64 · July 2, 2011, 02:58

Hi all, As being a new owner and really lovin the car i want to do any preventative maint. i can. My car is in the USA and i was wondering if these pre-cats are on my vehicle? Thank you in advance if you know. Joe By the way it is a 2001

smarty72 · July 2, 2011, 03:30

Hell yes. There in there because of your (USA) stringent emission control regulations. They didn't ever need to be in the UK spec two's!

Treboeth · July 2, 2011, 04:23

Quote from: "smarty2072"Hell yes. There in there because of your (USA) stringent emission control regulations. They didn't ever need to be in the UK spec two's!

Not sure if it`s the whole USA I thought it was just California?

If not I`ll soon be corrected by someone more knowledgeable s:bowdown: :bowdown: s:bowdown:

smarty72 · July 2, 2011, 11:39

I can't imagine they would have restricted it to just ones sold in California. If so why did they leave them in UK spec models?

Treboeth · July 2, 2011, 16:39

Quote from: "smarty2072"I can't imagine they would have restricted it to just ones sold in California. If so why did they leave them in UK spec models?

You misunderstood me I know the precats are in all cars just not sure if they are required throughout the USA for emissions as I understood it just to be required for Caliifornian emissions reguilations,

markiii · July 2, 2011, 16:46

corretc only cali

motojoe64 · July 2, 2011, 22:10

So out they will come! So how many cars have had this pre cat failure? Its hard for me to understand toyota engineering a part that could have such a failure. on my third toy. pick up. each one going well over 200k miles. no problems with any of them to speak of. well maybe the 1988 rusting big time! Thank you all. Cannot say how happy i am with my mr2. im 47 years old and smiling like in my go cart at 12 years old!

mrzwei · July 2, 2011, 22:48

Quote from: "motojoe64"So out they will come! So how many cars have had this pre cat failure?

The stats are now a bit skewed because so many people have either taken them out or replaced the manifold, mostly I think quoting no damage to the precats.

motojoe64 · July 2, 2011, 23:45

Thanks for the fast responce. As i plan to keep the car for a long time would you recommend gutting or replacing the manifold? and what would be the one of choice if it gets replaced? I plan on installing the team moon cat back dual exhaust while at it. Thanks again!!

Anonymous · July 5, 2011, 21:58

Only had my car '54' red edition with 26k for two week's but ordered a Che manifold , TTE exhaust and new gaskets, stud's etc.
Spoke to my Toyota dealer who said they could do the job for me (just had it in last saturday for a service) but kept saying are you sure you want to do this (don't know why) I said yes and as soon as my manifold arrive's (the other part's were ordered through the dealer) I would book it in.
Can't wait to get the work done and have piece of mind.

Mark.

Anonymous · July 8, 2011, 20:10

Just went to the mechanic and asked him to open one of the o2 sensors.. I peeked inside and it all seems fine... ***RELIEFFFFFF*** Car's done 95k (02 reg)

I'm looking forward to do this de-cat thing real soon - as soon as I can get my hands on an o2 sensor socket. lol
Anyone knows where I could get them around North London?? My local Halfords (enfield retail park) dont have them, and online stores take 3-5 working days to dispatch.. This seems loooonggg....

Is there any way to remove the heat shield and then open the o2 sensor with an adjustable wrench???
Thanks folks

smarty72 · July 8, 2011, 20:32

You can undo the four bolts which hold the heatshield in Place but it won't lift over the o2 sensors.

Anonymous · July 9, 2011, 17:42

Damn, I couldnt even open one single bolt on top of the heat shield.. It's beem on WD40 since yesterday, and still didnt work...
Have been trying for the last 2 hours..
Spanner doesnt fit - maybe cuz of rust...

Next stop: Mechanic

Anonymous · July 9, 2011, 18:07

the 4 bolts just very nicely. took a grinder to mine to get it off. as for the sensor dont use adjustable as it can round but without the shield any 22mm spanner will do.

Anonymous · August 11, 2011, 15:01

I just had mine done... Surprisingly, the mechanic didnt take the o2 sensor out.. Thats how he did it:
Car on ramps.. Veery high s:P

s:P
opened i think 3 or 4 bolts, which I think separates the main cat...move the cat away...
then from the bottom of the car, you could see the precat (which was still perfect honeycomb).. put a long screwdriver thing and break the damn thing...
Make sure u cover the other opening for the cat, as dust can go in...
All white stuff out, put the 4 bolts back and tighten the cat back...

Anonymous · August 11, 2011, 19:43

Quote from: "neel35"I just had mine done... Surprisingly, the mechanic didnt take the o2 sensor out.. Thats how he did it:
Car on ramps.. Veery high s:P s:P
opened i think 3 or 4 bolts, which I think separates the main cat...move the cat away...
then from the bottom of the car, you could see the precat (which was still perfect honeycomb).. put a long screwdriver thing and break the damn thing...
Make sure u cover the other opening for the cat, as dust can go in...
All white stuff out, put the 4 bolts back and tighten the cat back...

That is the laziest method I have heard and may end up costing you a new engine if any particles left behind in the manifold make their way to the cylinders and score the bores as there is no way all the precat debris was cleaned out with this method. s:? :? s:?

markiii · August 11, 2011, 19:45

not to mention teh risk of damaging an 02 sensor

rodenal · August 17, 2011, 10:27

I dunno, it depends how much effort he made to initially protect from the dust going up the way and when done to clean out the manifold. Still not going to be an ideal way to do it though and pretty risky.