Precat removal - How I did it...

[dipper84]

emissions?! bummer!! will this effect its MOT??? ive got a new sensor ready to be fitted so ill pop it in tonight and hope that will solve it. i think it could be where i grinded the bolts off the cat - exhaust pipe and probably damaged the sensor in the process? ill keep you posted on the results of fitting the new one.

[dipper84]

just another thought (which could be crucial) is i keep getting a p0135 too, so could this mean the engine is running rich as the o2 sensor is dead, creating nore emissions causing code P0141? or is that a dead sensor rather than an incorrect reading?>

[anthony82]

Replaced my manifold yesterday and it was a pig! Main problem was removing the top heat shield so I could get access to the manifold engine mounting studs because all the screws had corodded leaving no real head to put the socket onto. Ended up drilling the heads off and bending the heat shield out of the way to get in.

After that, it was fairly straight forward just needed a long bar to get the leverage to undo everything. I had already removed the pre-cats from a second hand manifold so armed with new gaskets it didn't take too long to get it all back together again. Ran out of time so haven't had chance to start her up and test for leaks yet, but keeping my fingers crossed!

With regards to heat shields, are they essential to put back on to prevent damage to bodywork etc? The lower one fitted to my manifold has corroded badly around one the mounting holes so is no longer fixed with the screw so may start to vibrate. Left it for now, but only option is too remove or replace with new. Any ideas on cost?

[catkins]

Dragging this up as the first post is VERY helpful.

My 2 has done just over 80k miles but I havent a clue whether its pre cats have already been removed (I'm hoping they have for my sake). It's a 2001 Y reg.

My sister in law bought a 2000 reg MR-S 4 years ago and hers WERENT removed, even at 60K miles!

How long do they normally expect to last??

Primarily, my question is, how exactly can I check them myself? I'll admit, being a woman, cars have never been my strong point or a source of interest, however since having my 2 I've made an effort to take time to find out things about how the car works and performs as well as the aesthetics of it. My partner and his dad are pretty good with cars and refuse to pay a garage for anything less than an MOT lol. His dad removed his sisters pre cats when she got her MRS but I'm hoping my partner and I can have a look, and if need be, remove them without having to take some of his precious time.

Does anyone have any pics of before/after and where/how I need to be looking to check their position and condition.

Many thanks all

This SEARCH facility really is handy!

I love this smiley.... RANDOM!

[ad_car_08]

catkins - What you'll need to do is get hold of an oxygen sensor socket. It's dead easy to recognise, it looks like a deep spark plug socket, but with a section out of the side to allow the wire to poke out the side. When you get one, all will become clear

Here's a piccy -

Then what you need to do is open your boot lid and you'll see your domed manifold heatshield directly infront of you. Coming out of each side of that is your oxygen sensors. Use your new socket to unscrew them, grab a torch and have a gander inside the manifold - you should see a white honeycomb intact. Replace the sensor and do the same for the otherside.
IF your white honeycomb is broken or there's a size'able hole in it, it tends to mean bad news.

A more comprehensive walkthrough with pictures is somewhere on the forum if you search, it's talked about often enough!

[catkins]

Thanks for that

Yeah I have done a bit of searching and found bits and bobs - all very handy!! I think my other half knows where he is looking so will try and do it this weekend.


I would hope and assume mine, a 2001 plate having done almost 90K, would have already had them removed.

I hope!

[nelix]

Unless the car has been owned by a previous club member it is highly unlikely the pre cats have been removed. However no need to panic as plenty of cars have done this mileage and higher with no problems.
However, be pro active and whip those bad boys out Clare.

Russ, don't even think about it.......................

[ad_car_08]

Yeah, I bought mine with the best part of 90k miles on the clock. The owner hadn't a clue when I asked about the precats, and sure enough when I checked, they hadn't been taken out.

2 years later, I don't seem to be doing too badly

[JohnB]

I removed the pre-cats on my lasses 05 plate 2 on monday.....I'd checked them when she got the car 5 months ago, they looked tiptop but having read all the info on here I was always gonna remove them soon as I got 5 mins.

My mate has a garage and gave me use of a ramp for an hour.......top heat shield bolts had to be removed with the grinder, everything alse was a doddle.....the 3 amigos came out no trouble at all....I'd taken the precaution of having new ones just in case but didn't need them.....plenty of plus-gas before hand did the trick.
The cats were still in excellent condition, no signs of degradation.....the car has 42k on.
I completely removed the top heat shield bolts from the manifold and welded new bolts in place....new manifold/head gasket and 2 new manifold/downpipe gaskets...all boxed back up....job's a good un.

Thanks for posting the "how to".

[catkins]

catkins - What you'll need to do is get hold of an oxygen sensor socket. It's dead easy to recognise, it looks like a deep spark plug socket, but with a section out of the side to allow the wire to poke out the side. When you get one, all will become clear

Here's a piccy -

Then what you need to do is open your boot lid and you'll see your domed manifold heatshield directly infront of you. Coming out of each side of that is your oxygen sensors. Use your new socket to unscrew them, grab a torch and have a gander inside the manifold - you should see a white honeycomb intact. Replace the sensor and do the same for the otherside.
IF your white honeycomb is broken or there's a size'able hole in it, it tends to mean bad news.

A more comprehensive walkthrough with pictures is somewhere on the forum if you search, it's talked about often enough!

Thanks for this info. Just a question though. Is the oxygen sensor likely to break if I try removing it? I've had it break on my Punto when the garage went to replace a section of my exhaust and it ended up costing me an extra £70 to have it fixed. OR, might the manifold bolts corroded and therefore likely to shear?

eurgh.... my partner reckons it "sounds like a nightmare" and we are more worried about other things around it breaking in the process of looking and potentially removing the precats. My girl has had three previous owners, all female, and by the sounds of it from the people I bought it from, all unlikely to have been club members. So its highly likely the buggers are still there.

[KTM_RIDER]

just gutted mine (2000 W with 98k miles) will do a more detailed post in due course.

Is the oxygen sensor likely to break if I try removing it?

No. Perhaps the one on your fiat was more exposed to road salt and had therefore corroded solid. the sensors on the '2' are fairly well protected from the elements.

OR, might the manifold bolts corroded and therefore likely to shear?

Given the age of your car it is possible that one or more of the manifold to cat bolts will be awkward to remove.

eurgh.... my partner reckons it "sounds like a nightmare"

Even for someone with reasonable mechanical aptitude who has access to a decent range of tools, it can still be a bit of a hassle I would agree, but nothing like the hassle of what might happen if you leave them in.

The idea of having to spend a grand on a new engine for a car I've barely driven was my idea of a nightmare!!!

[catkins]

Thanks very much for the reply.

I do appreciate that the hassle of the checking, even if they are not there, is less hassle and expense than risking it!! Just wanted to check really before we went ahead with it, thinking we could do it in a few hours and be on. I can't be without a car as I travel a lot with work so the thought of something breaking and me having to arrange to get to a garage is more what Im worried about in the short term.

I guess we will have to put a date in our diaries to do it on a Saturday morning and when we are not busy on the Monday (and that I have just been paid ) so that if anything does need more time and expense, it's not going to be a panic job.

PIcs would be greatly appreciated. It looks like the pics on the first post of this thread dont work any more

[KTM_RIDER]

took some pics, will upload in the next few days.

First things first, buy the socket, you can get one here:

http://cgi.ebay.co.uk/DRAPER-55540-LAMB ... 1098wt_706

and if you're very lucky you wont see any white mesh (the precats) when you shine a torch down the holes.

On the assumption that they are still there (and given that unlike me you don't have the use of another car) I strongly suggest that you either get a second hand manifold or go for a new 'che' manifold. This is because I found that easily the worst part of the job was not getting the manifold off the car, but preparing the manifold for re-use (specifically replacing the 3 mani to cat studs, as none were re-usable on my manifold).

Say you go the s/h manifold route - then obviously any time you may need to spend prepping it (i.e knocking out the pre-cats and /or replacing mani to cat studs) can be done at your leisure without interfering with you using the car.

[uktotty]

But if you do it that way you need 2 gaskets

[KTM_RIDER]

er, I count 3 actually (2 mani to cat and 1 mani to engine)

But yes, I recognise she would need to buy a new engine side gasket, but presumably this would cost alot less than the manifold anyway (new or s/h). She said she needs her car, whereas mines just an occasional toy so I could put up with the hours of swearing at my ugly stock manifold.

To be fair though, i would have got there quicker with a mains drill instead of my battery powered crap 'n' decker that lasted about 15 mins between charges................

[catkins]

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!)