CAT/exhaust replacement for 03 petrol Avensis - OEM or not?

[Christyt999]

Hi all - grateful for any advice on this.

After service my non Toyota garage said my GS VVT-I hatch 1794cc 03 petrol Avensis had a small leak in join between the secondary (back?) CAT and back part of exhaust.

They said the CAT and exhaust section looked corroded and would need replacing before long anyway and though I could probably get a weld for now, the job would need doing soon. They said it would be cheaper to do both together.

There's no engine light coming on at this stage.

They've quoted around £300 to fit an aftermarket CAT and £120 for a rear pipe - presumably not stainless steel.

I've been reading that aftermarket CATs tend to be very shortlived. The car has been rock solid so far though oil consumption is high.

It's quite an old car but I'd like to keep it going but the quandry is whether to go aftermarket or not? And if so, what brand of CAT would be the best option? I've heard Magna-something and in one forum EUROFLO was recommended.

Can anyone advise what to do? Get a weld and soldier on until the engine light comes on and the exhaust falls off? Or bite the bullet now?

Many thanks

 

 

[Konrad C]

From experience, if you intend to keep the car for a long time, then go for the original. The fitting will be better. Euroflo is fine and most exhaust seem to use a mix of aluminium, zinc coated steel and stainless steel. 

I bought an exhaust from Euro Car part for my old Mk1, but the rear box shape was slightly different. This meant it touched the undershield. I changed it to Euroflo and it was far better. 

For some reason, it is hard to source the original exhaust outside Toyota, unlike items like Denso spark plugs and O2 sensors.

Make sure you use mild steel nuts and bolts. Stainless steel has issues with heat and the nuts and bolts weld together. I know from experience when trying to adjust the exhaust later. 

Another thing. I used angle grinder on the old corroded bolts, and the exhaust came part okay. If the mid/cat section is not too bad, then the rear may be all you need. Also there is a gasket that can be replaced. It depends on the corrosion and condition.  

[TomdeGuerre]

4 hours ago, Konrad C said:

From experience, if you intend to keep the car for a long time, then go for the original. The fitting will be better. Euroflo is fine and most exhaust seem to use a mix of aluminium, zinc coated steel and stainless steel. 

I bought an exhaust from Euro Car part for my old Mk1, but the rear box shape was slightly different. This meant it touched the undershield. I changed it to Euroflo and it was far better. 

For some reason, it is hard to source the original exhaust outside Toyota, unlike items like Denso spark plugs and O2 sensors.

Make sure you use mild steel nuts and bolts. Stainless steel has issues with heat and the nuts and bolts weld together. I know from experience when trying to adjust the exhaust later. 

Another thing. I used angle grinder on the old corroded bolts, and the exhaust came part okay. If the mid/cat section is not too bad, then the rear may be all you need. Also there is a gasket that can be replaced. It depends on the corrosion and condition.  

Very good advice Konrad, stainless steel nuts are legendary for thread galling. Don't know if they ever developed an effective anti-seize for them I know copper grease (Copaslip) didn't work but maybe there's some wonder lube out there. Back in the day they used brass nuts on steel studs for all the manifolds. Sure they'd slacken off and go bell ended and even strip out the threads but they didn't give the trouble stainless does. 

[+robster+]

soldier on wait till next mot see whats what

[Christyt999]

Thanks so much for your replies.

I went back to the garage and the guy seemed a bit more relaxed. He said if it were him, he'd wait for the MOT and see if it passed. He said it was a very small leak so he'd expect it to pass at this stage.

Then he said he thought the whole back section of the exhaust (and back CAT) needed replacing due to corrosion (though no engine light's come on as of yet and I don't know if you can tell from the outside if a CAT needs replacing????) but he said whether I went for official parts or aftermarket depended on how long I wanted to keep car for - as you said Konrad.

He's also flagged weak front and back links though I'm not hearing any noises yet.

It's got 85,000 on the clock and so far has been rock solid engine wise so far.

I'll see how the MOT goes - it's in 2 weeks - and then probably run it until the next service and see what's what then.

Thanks for the tip on the stainless steel nuts though - I'll be sure to mention it if I get anything fitted.

Out of interest, how long did your Euroflo exhaust last Konrad?

[Konrad C]

The Euroflo was on the car since August 2015. The back box fitted better than the Klarius version I fitted the year before. The Euroflo system looks more like the original than the React/Klarius combo, I bought from Euro Car Parts. The both brands come with stainless steel catalytic converter sections. The shapes differ. I actual have a used React Cat' for a Mk1. I will sell that as it is mint. 

Here is a picture after cutting off the corroded bolts. Original Mk1 back box joint after 17 years.

The issue is the fit. Make sure it is not touching anything, and that is aligned and not transmitting any resonance. 

The Mk2 "should" be easier, but you never know what to expect. I sold my Mk1 a few months back. Hopefully I should not need to touch the Mk3 yet.

There is a lot of reading and even though your car is different the principals are the same. A friend had a new back box fitted on his Mk2, and it seemed fine.  

[marty_c83]

My mk1 1.8 (non vvt) has a non Toyota centre section and rear box, sounds very raspy like a bad sports exhaust and it does rattle the heat shields. Not too fussed as its just a work run about instead of a van but can see that it would annoy most folk. Not sure what brand it is tho.

Sent from the moon using telepathy