Help me understand the Hyundia / Kia 2.0 and 2.4 problem?

[KGMtech]

Sorry if this seems like a beaten horse, but I am trying to be fair and understand where did the Theta engine manufacture process or original engine design mess up.

So we all know that Hyundia admitted that manufacture of the Theta crankshaft left out the proper cleaning of debris in this crank that led to debris circulating in the engine and causing knocking and failure of the engine.

My question is: if they did a proper job of manufacturing with all the proper post machining cleaning, would this be a reliable series of 4 cylinder engines? or is there something else that was also done poorly to lay the trap for the engine? Additionally if this engine was made in other markets, did they also skip the same cleaning step or was it just in North America?

Let me know if just 1 big mistake caused this or was it more than just this?

 

[MParr]

Something I learned from a recently retired Hyundai Master Tech is something I didn’t know. Hyundai and KIA uses 8mm bolts for the cap screws with aluminum alloy connecting rods and caps. An 8mm bolt is very close to 5/16” SAE.
It’s not only the USA made Theta II engines with the grenading problem. There are many different problems causing the engine failures. The “official “ cleaning process was one. I had a 2013 Optima 2.4. It was included in the recall, tested, and Orange dipstick added. We put 60,000 miles on that car and it never gave us a minute of trouble. We used 5W30 oil and changed every 5,000 miles. NAPA Gold or Hyundai OE oil filters were used. We ran 93 octane gas in it and we never hit the Eco button. Using the Eco mode lugs the engine. That is not a good thing.

 

[Greasymechtech]

That cover story about debris was a joke.

Too many drivers short trip their engines. This adds fuel to the oil. The oil becomes worthlessly thin while accelerating wear. Add in the majority don't want to change their oil at a sensible interval, or ever top it off, leads to a short life and blaming the automaker.

They couldn't tune GDI high compression for power and emissions without running pig rich too often, especially with an 87usa fuel recommendation.

Other markets aren't forced to use the thinnest best MPG oil.

My mistake was treating it like my previous Mazda/Honda/Toyota's...

I've seen dozens of these failed and all were either sludged up or without oil. Automakers underestimate the US consumer too often.

Hyundai was too kind to too many negligent owners after the class action, and not kind enough to others that had well maintained failures and denied warranty help.

 

[Robster]

The problem exists, but as a percentage of engines produced worldwide, it's not a big number. The debris theory came out early as the problem became well-publicized, but the problems persisted years after they'd allegedly fixed that problem. Personally, I think it's the confluence of a high-tech (GDI, GDI-T) engine being mass produced, combined with Hyundai customers who as a whole are not as maintenance-savvy as the usual BITOG member. These engines NEED routine maintenance (oil changes at shorter-than-you'd-think intervals), along with fuel system cleaners at every OCI. Some of these engines burn oil and many owners won't check anything under the hood until a light comes on. These factors conspired to give these otherwise reliable engines a bad rap IMHO. I'm on my 2nd Theta II and I haven't had any issues with either one, but I'm on top of maintenance.

 

[GR_CoB]

Can't remember where I read this, but there was something specific about wristpins. It's been a while, and I can't find that article anymore. But something about the metallurgy of the wristpins caused them to seize in piston without a warning in high heat conditions, instantly throwing a rod through the block. That theory was backed up by the fact that majority of thrown rods happened while vehicles were going highway speeds continuously for 2 hours or more.

 

[doitmyself]

I'm not sure if this is relevant, but the Dundee, Michigan versions of the GEMA engine don't seem to have the issue's of the Hyundai/Kia versions. This makes me think that Hyundai/Kia made other mistakes beyond the debris claims. The newer Tigershark GEMA engine from Dundee had some initial oil use issues, but it is claimed that was fixed with engine computer program changes.

 

[wemay]

That cover story about debris was a joke.

Too many drivers short trip their engines. This adds fuel to the oil. The oil becomes worthlessly thin while accelerating wear. Add in the majority don't want to change their oil at a sensible interval, or ever top it off, leads to a short life and blaming the automaker.

They couldn't tune GDI high compression for power and emissions without running pig rich too often, especially with an 87usa fuel recommendation.

Other markets aren't forced to use the thinnest best MPG oil.

My mistake was treating it like my previous Mazda/Honda/Toyota's...

I've seen dozens of these failed and all were either sludged up or without oil. Automakers underestimate the US consumer too often.

Hyundai was too kind to too many negligent owners after the class action, and not kind enough to others that had well maintained failures and denied warranty help.

This, pretty much hits the nail on the head.

 

[MParr]

That cover story about debris was a joke.

Too many drivers short trip their engines. This adds fuel to the oil. The oil becomes worthlessly thin while accelerating wear. Add in the majority don't want to change their oil at a sensible interval, or ever top it off, leads to a short life and blaming the automaker.

They couldn't tune GDI high compression for power and emissions without running pig rich too often, especially with an 87usa fuel recommendation.

Other markets aren't forced to use the thinnest best MPG oil.

My mistake was treating it like my previous Mazda/Honda/Toyota's...

I've seen dozens of these failed and all were either sludged up or without oil. Automakers underestimate the US consumer too often.

Hyundai was too kind to too many negligent owners after the class action, and not kind enough to others that had well maintained failures and denied warranty help.

Thank You!

 

[KGMtech]

Thanks for the insights that explain why some engines last with good maintenance and so many fail BIG because of either no oil, too much dilution by fuel or just no oil changes period.

 

[dubber09]

I may be wrong by I beleive they started installing oil squirters to oil and cool underside of the pistons in engines built in Korea soon after they ran into the issue. NA engines didn't get those for a long time.

 

[Blinker]

I may be wrong by I beleive they started installing oil squirters to oil and cool underside of the pistons in engines built in Korea soon after they ran into the issue. NA engines didn't get those for a long time.

The Theta II 2.4 and 2.0T have had piston oil squirters since the engine came out for the 2011 model year. I'm not sure about the naturally aspirated Theta II 2.0 though

 

[Number_35]

Something I learned from a recently retired Hyundai Master Tech is something I didn’t know. Hyundai and KIA uses 8mm bolts for the cap screws with aluminum alloy connecting rods and caps. An 8mm bolt is very close to 5/16” SAE.

Is 8 mm too small for this application?

What size do Toyota, Honda, and Mazda use?