[blake997]

Hey all,

I've seen a fair few posts on this issue and had my own experience with it, so just thought I'd set the record straight on what is actually happening as there seems to be incomplete information getting around.

Background - I'm a vehicle builder by trade, and have quite a few years under my belt preparing and spannering on race cars and all things mechanical.

My daily is the 2014 i30 Active petrol, 6 speed manual. 185,000kms on the clock.

The car is great, really awesome chassis, if a very under-powered engine, and lacking a little on reliable and consistent build quality from the Koreans. (Dead head unit, dead wheel bearing, so on). Thankfully, pretty well designed and easy to work on. Nothing like the god awful Astra / Vectra from Holden.

Anyways:

Issue that presents itself on these cars / engines. -

Car gets hard to start, initially.

Car does not want to rev. Especially doesn't want to rev past 3,000rpm - 5,000rpm. First under load when driving, and then even in neutral.

Car seems like it is in a limp mode.

Car stutters and even conks out after revving. As if it is losing fuel or spark.

Car seems like it is down on power, runs rough.

Car functions somewhat like an engine that has worn valve springs.

Car functions like an engine with a bad or dirty MAP / MAF sensor.


NOW:

My i30 developed these issues over about a week or two, until I really got a chance to look at it. It was due for its 180,000 service, so I started doing the typical things just to check them off the list regardless.

Plugs, coils, injector service, new fuel pump and filter.

I wasn't having much success and the engine started throwing bad MAP sensor codes. So I proceeded to do the extra (as in extra expensive ancillaries).

MAP sensor, new throttle entirely (TPS is one piece elec sensor), knock sensor, both cam sensors. Still no bueno.

As the title would suggest, the part that is causing this issue (and was the next item on my list) is the manifold cat.

Hyundai are well aware of this issue. And this is the aforementioned "warranty claim issue for catalytic converter" that frequented the forum over the years. Even on new and low kilometre cars.

So, what is actually happening here and why would Hyundai be wary of replacing this part?

At the back of the engine, between the firewall and the block, the exhaust header manifold sits on the engine.

WITHIN this manifold collector is a ceramic catalytic converter element, quite tightly fitted (but not tight enough alas) with a myriad of honeycomb shaped holes running through its length from one side to the other. This element nearest the engine is a "quick warm up" cat, and in it sits the upstream Lambda sensor. There is ANOTHER cat in the next muffler down, just behind the downstream LS. These downstream ones are typically O K.

Despite theories and rumours, this manifold cat converter element DOES NOT "get blocked up" with gunk in the sense many seem to profess. What it does do is CRACK. Due to heat and vibration. Of which, even the slightest mis-alingment of the holes running through its length will cause an effective seal on the entire exhaust system, which then starts choking the engine, robbing power and throwing a number of (unrelated) engine codes. They APPEAR fine upon removal. Until you take a grinder to the manifold collector canister, peel back its sheetmetal covering and look inside to see the cracked cat element blocking the path of flow.

Back to the "why would Hyundai be wary of replacing it under warranty".

Well, now here's where things get interesting. The Manifold Cat-type is a $5,300 spare part to buy from Hyundai Service. No, that is not a misprint. Verified twice. Yup. FIVE THOUSAND THREE HUNDRED DOLLARS AUD. Ferrari money for a Hyundai part. And of course, PLUS labour if you aren't handy. A car like mine is a $10,000 purchase for the entire i30, so naturally that isn't even a consideration for a serviceable item.

And it's a real bastard to fit. It must be taken out under the car with the driver's side upright mostly disassembled to slide the drive-shaft out of the way, allowing the manifold to slip out underneath the car.

Thirdly, using such a delicate ceramic material instead of a metallic cat so close to an exhaust port is just foolish (however stainless metallic elements shouldn't be that close to that much heat either as they can melt and block up). So in my view it is poor design and a known 'fault' if you will.

The only *real* option to repair, is to get a second-hand one, but obviously this presents a rather blatant issue. A second-hand one, despite trying to obtain one in as low kilometre a condition as possible, could still be cracked - especially if from a salvaged accident car - OR even imminently about to crack, after you spend all the time taking it out and replacing it. The element cannot be purchased separately, either.

FAILING THAT:
You can do what I did. Slice the manifold open, take out the entire cracked element, and weld it back up. Reinstall.
This will present persistent starting issues (which are liveable with, 5 - 7 seconds to start the car when cold) as the quick warm up Lambda is now getting odd readings with no backpressure on the engine, and an odd hollow sound under load as the little engine is now breathing through a giant 5.5in exhaust collector, also. FYI, removing the second downstream cat and leaving the manifold cat installed (if in good condition) will provide a VERY nice sounding engine.

In addition, it is likely that simply putting "any old metallic aftermarket cat pipe" in its place there will not fix the issue either. As the manifold system is very carefully designed for that specific cat element and backpressure design.

When I get some time, I will pull it back out and weld in a narrower collector or an auger barrel to help displace all the volume and bring back back-pressure., which should improve things. But at the moment it is functioning just fine and driving with full RPM power again.

Hope this helps.

Also, kicking myself I didn't take any pics of the elements etc!

EDIT - I'm also aware of some aftermarket options in Europe, but it's hard to see compatibility.
In that same vein, there are lots of 2017 - 2019 manifold cats available lowish kilometre second hand (still expensive) but again I'm unsure of compatibility. They LOOK the same. But the heat shielding I believe is different. Potentially more.

[CraigB]

Yeah it's a strange header design they did, I went another option...got some aftermarket headers and threw the factory one's in the bin

"Note" 2017 to 2019/20 PD petrol models use either the 2ltr or 1.6 turbo in Australia so their manifolds wont be compatible with the GD 1.8ltr.

[Dazzler]

Hi Blake.

  and thanks so much for doing that amazing 1st post. I can safely say that is by far the longest 1st post ever on this site in its 12+ year history.

Now, they say you learn something every day. As co-founder of the site and having owned four i30s in the last 12 years, I know as much as anyone and more than most about i30s. Surprisingly, I wasn't aware of this being a big issue with the 1.8 motor.

There is plenty of discussion on here about the 1.6 diesel going into limp home mode and refusing to rev past 3000 rpm (mainly due to fuel pump/fuel filter housing issues) but very seldom does the petrol 1.8 get flagged on here with the fault you described.

Now I'm not doubting you. Sounds like you have great credentials and plenty of experience.

[blake997]

Yeah it's a strange header design they did, I went another option...got some aftermarket headers and threw the factory one's in the bin

"Note" 2017 to 2019/20 PD petrol models use either the 2ltr or 1.6 turbo in Australia so their manifolds wont be compatible with the GD 1.8ltr.

Hey mate, can you recommend me some (if they're made for my 1.8)?

I can only find the German stuff, and as mentioned, it's hard to glean the compatibility when translating! Haha.

Hi Blake.

  and thanks so much for doing that amazing 1st post. I can safely say that is by far the longest 1st post ever on this site in its 12+ year history.

Now, they say you learn something every day. As co-founder of the site and having owned four i30s in the last 12 years, I know as much as anyone and more than most about i30s. Surprisingly, I wasn't aware of this being a big issue with the 1.8 motor.

There is plenty of discussion on here about the 1.6 diesel going into limp home mode and refusing to rev past 3000 rpm (mainly due to fuel pump/fuel filter housing issues) but very seldom does the petrol 1.8 get flagged on here with the fault you described.

Now I'm not doubting you. Sounds like you have great credentials and plenty of experience.

Cheers mate, and yep I hear you 100%.  Just also including heaps of talks with those in the industry and Hyundai themselves etc also within that recurrence of the issue. They were even considering talking me into an entire motor rather than just the manifold cat. Lol.

My hope is that if anyone else gets the issue, they'll at least stumble across this when Googling, so I tried to fill it with as many buzz words as possible.

I sensed it may have been a manifold cat issue from the beginning but was hoping it wasn't because they are a real pain to do. And in many ways it's not quite a Hyundai-specific thing. IMO you should never place one so close to the exhaust ports. BUT. Particularly, it should be snug enough inside its casing that it also *cannot* crack, which appears to me that the i30 ones aren't. And you can imagine the kind of vibrations that rattle through that part, and the delicate material.

One thing is for sure though. They do bloody work, and a HELL of a lot better than the old cats in the 90s and early noughties used to.

The old Commodore ones would clog up in a few months use. These ones do a great job of converting the gases - and you can definitely notice now with it removed how fuely and unruly the exhaust smell now is without that catalytic conversion.

[CraigB]

With the 1.8 not used in Korea or the US it makes performance parts a rarity, you’ll likely have to get some made up.

If you can get the headers off a wreck and get a good exhaust fitter/welder to copy should be doable.

I was going to do the same through a local Sprint car builder but managed to find some Maintec headers for my 1.6 via Shark Racing Korea.

[blake997]

With the 1.8 not used in Korea or the US it makes performance parts a rarity, you’ll likely have to get some made up.

If you can get the headers off a wreck and get a good exhaust fitter/welder to copy should be doable.

I was going to do the same through a local Sprint car builder but managed to find some Maintec headers for my 1.6 via Shark Racing Korea.

Thanks mate, I figured so. Could fab some up but kinda don't want to put in the effort lol. A lot of time, plus argon to purge the stainless piping when tigging.