Oil type, no big difference | GDI carbon

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wemay

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From what I've seen after visiting a few (mostly Santa fe Sport [2013-present] and Sonata [2011-present] forums over the past few weeks, oil type does not matter. Noack %, Synthetic vs Conventional, OCI, catch cans, fuel octane, driving style, ambient temps, nice looking UOA... nothing makes a definitive difference. Some folks using full synthetic get deposits early and some using Conventional haven't had any issues yet, and vice versa. Most of these are around 50-80K miles (this is typically when symptoms begin to show, like hard starts, knocking, pinging, vibration under acceleration and stumbling at low RPM). But nailing down who gets it based on oil used seems fruitless since dino, blend and syns get it, and dino, blends and syns....don't.

Now to be clear, most on those boards have not had any carbon issue regardless of the paranoia they exhibit. I am referencing those who have posted that they have, which is a decent amount of folks.
 
Everyone talks about carbon deposits with GDI, but how do they know how much this happens? Where can you see this? Sounds like a lot of speculation from people who haven't torn their engine apart to check whether it even happens or not.
 
I wouldn't be surprised if that were the case. I would think the biggest driver of carbon build-up is how much oil mist/vapor is actually passing through the PCV system from blow-by.
 
Originally Posted By: Nick1994
Everyone talks about carbon deposits with GDI, but how do they know how much this happens? Where can you see this? Sounds like a lot of speculation from people who haven't torn their engine apart to check whether it even happens or not.


It happens a lot. Every single DI BMW engine I have seen has serious carbon build-up in the intake ports and on the valves.
 
Originally Posted By: 1JZ_E46
Originally Posted By: Nick1994
Everyone talks about carbon deposits with GDI, but how do they know how much this happens? Where can you see this? Sounds like a lot of speculation from people who haven't torn their engine apart to check whether it even happens or not.


It happens a lot. Every single DI BMW engine I have seen has serious carbon build-up in the intake ports and on the valves.
BMW had carbon issues when they had port fuel injection in the early years.
 
My model/year car is plagued with deposit issues. The TSB work I have seen done on majority of the cars read about was around 35k. On mine, they couldn't replicate until 73k, and even then I wasn't having any consistent trouble with it. The offered and I told them sure. So new rings went in and whatever else. I am a believer in low NOACK for DI deposit, but then the ring tension was so low in the IS's that the PCV would shoot a stream of oil into the intake. Beat on the car for a little while, and you need to top off the oil.
TSB or anything else has not been able to replace the cleaning power of gasoline though, still have to clean the carbon off. Just depends how often.
 
It happens on every single Kia and Hyundai GDI car. Every single one over 30k Miles I’ve had apart has had junk on the intake valves. MPI engines USUALLY don’t. I’ve had hundreds of Kia intakes off over the last 5 years. I’ve seen some MPI cars with a quarter million miles with spotless intake valves. GDI is a joke.
 
Kia/Hyundai is bottom of the line anyways so I would expect problems. I would move towards something known for better reliability if you don't have mechanical skills to fix your issues.
 
Originally Posted By: Silverado12
Kia/Hyundai is bottom of the line anyways so I would expect problems. I would move towards something known for better reliability if you don't have mechanical skills to fix your issues.


LOL
crackmeup2.gif

Here we go again. Clearly not up with the times.
 
Hah!! Knee jerk invitation for Hyundai/Kia bashing just waiting for the next next opportunity.

My question would be if I have an over 5 year old Hyundai DI car with no apparent DI-related issues and 80K miles ( as I do ) does that make it a joke...or does the joke center around getting 120K-150K miles ( how long I typically keep a car ) with none of these issues?? Does that make it an anomaly at that point??

I know too many people with DI cars and heavy miles to take this incessant B.S. seriously as a blanket statement.

Personally, I'm waiting for the 2019 Excel to come out because it's supposed to have side draft carbs.
 
Originally Posted By: Nick1994
Everyone talks about carbon deposits with GDI, but how do they know how much this happens? Where can you see this? Sounds like a lot of speculation from people who haven't torn their engine apart to check whether it even happens or not.


The best people to ask are the techs servicing them at the dealerships. One or two people's personal experiences don't mean much.
 
I have to believe that driving patterns and possibly fuel choice matter here. A typical GDI vehicle that sees 80% of its trips less than a few miles running on cheap generic 87 octane gasoline would seem to me one of those mentioned with buildup at 30k. There are a lot of these situations out there. Many drivers who own a GDI don’t even know what it means.
 
Originally Posted By: Vuflanovsky
Hah!! Knee jerk invitation for Hyundai/Kia bashing just waiting for the next next opportunity.

My question would be if I have an over 5 year old Hyundai DI car with no apparent DI-related issues and 80K miles ( as I do ) does that make it a joke...or does the joke center around getting 120K-150K miles ( how long I typically keep a car ) with none of these issues?? Does that make it an anomaly at that point??

I know too many people with DI cars and heavy miles to take this incessant B.S. seriously as a blanket statement.

Personally, I'm waiting for the 2019 Excel to come out because it's supposed to have side draft carbs.


As do I. The 2.0T in my sig...100K miles, no drivabilty issues or anything else to speak of. It's been the most reliable vehicle I've ever owned or leased. Yes, anecdotal.
 
I installed a catch can on our new Impala 3.6 DI (will post photos this weekend) as a bit of insurance against intake valve deposits. Whether or not it is needed, who knows for sure. I believe it should help prevent oil from getting to the intake. It wasn't hard to install, and can be removed easily if warranty is a concern. I like tinkering, so I didn't mind installing it.
 
Last edited:
Originally Posted By: wemay
Originally Posted By: Vuflanovsky
Hah!! Knee jerk invitation for Hyundai/Kia bashing just waiting for the next next opportunity.

My question would be if I have an over 5 year old Hyundai DI car with no apparent DI-related issues and 80K miles ( as I do ) does that make it a joke...or does the joke center around getting 120K-150K miles ( how long I typically keep a car ) with none of these issues?? Does that make it an anomaly at that point??

I know too many people with DI cars and heavy miles to take this incessant B.S. seriously as a blanket statement.

Personally, I'm waiting for the 2019 Excel to come out because it's supposed to have side draft carbs.


As do I. The 2.0T in my sig...100K miles, no drivabilty issues or anything else to speak of. It's been the most reliable vehicle I've ever owned or leased. Yes, anecdotal.


Yep. At a certain point, the empirical and the anecdotal come together...and my guess is that blanket statements about DI, carbon deposits, and what to expect and when, don't pass the smell test for people who take care of their cars or might have designs that are more or less prone to coking, etc.
 
Originally Posted By: demarpaint
Originally Posted By: Nick1994
Everyone talks about carbon deposits with GDI, but how do they know how much this happens? Where can you see this? Sounds like a lot of speculation from people who haven't torn their engine apart to check whether it even happens or not.


The best people to ask are the techs servicing them at the dealerships. One or two people's personal experiences don't mean much.


Think 69 Torino is a Kia tech …
 
Originally Posted By: 4WD
Originally Posted By: demarpaint
Originally Posted By: Nick1994
Everyone talks about carbon deposits with GDI, but how do they know how much this happens? Where can you see this? Sounds like a lot of speculation from people who haven't torn their engine apart to check whether it even happens or not.


The best people to ask are the techs servicing them at the dealerships. One or two people's personal experiences don't mean much.


Think 69 Torino is a Kia tech …


And there you have it! I've spoken to a few myself, it is also brand specific in many cases.
 
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