How to prevent oil and power loss in a Kia Soul GDI engine
compiled and written by westslope with valuable input from GeekOnTheHill, GeoSoul and SportsterDoc
Gasoline Direct Injection (GDI) engines can be more efficient than multiport injection (MPI) engines but require more pro-active maintenance as the intake valves in the GDI engines are not washed in fuel and can carbon up. Increased oil loss signals problems that could lead to increased operating costs, lower fuel efficiency, more polluting emissions, and in the worst case scenario catastrophic engine failure.
Here are a couple of pictures of intake valves. The first is from an MPI engine, the second is from a GDI engine. The intake valve is noticeably dirtier in the second photo. h/t bwdz75
![136985]( "136985")
![136986]( "136986")
This thread outlines a maintenance schedule that should prevent or solve problems and keep your Kia Soul GDI engine operating smoothly for years to come. It is primarily aimed at do-it-yourself mechanics but also contains suggestions on how to best use the dealership or qualified independent mechanic.
Strict minimum must do maintenance
Best practice maintenance suggestions
Synthetic oil suggestions
Synthetic oils have continuously improved over the years in ways that reduce engine wear, in particular timing chain wear, reduce oxidation and deposits, help prevent low-speed preignition (LSPI) problems in turbocharged gasoline GDI engines, and so on.
Popular brands of oil rated GF-6A and API SP are Pennzoil Platinum, Mobil 1, Castrol Edge Advanced and a promising new oil from Valvoline. Valvoline Restore and Protect.
Extended oil change interval varieties of motor oil can last 24,000 km / 15,000 miles and even longer in some multiport engines. They cost a little more. Examples: Pennzoil Ultra Platinum, Mobil 1 Extended Performance, Castrol Edge Extended Performance. Some of us shop them on sale but still stick to short oil change intervals.
The Kia dealerships sell a box of oil filters that are good, inexpensive and protect the warranty.
Do it yourself treatments
Two treatments are popular. They can be performed a week or month prior to regular, scheduled oil changes, or every few months depending on the condition of the engine and available fuel quality:
Intake valves
Clean out the intake valves with a spray can such as CRC GDI IVD Intake Valve and Turbo cleaner, Berryman Intake Valve and Combustion System Cleaner or Lucas Deep Clean GDI. This procedure works better with two persons but may be insufficient for vehicles already suffering significant oil loss. For serious oil loss, see below.
Fuel additives
Add a bottle of fuel additive which will dissolve carbon deposits in the engine and help keep the injectors clean. PEA stands for polyether amines and is a critical component of many fuel additives. Chevron Techron Complete Fuel System Cleaner is popular; Chevron does not currently report the PEA concentration preferring to keep it a 'Trade secret'.
Red Line SI-1 fuel system cleaner also has a high PEA content (25% to 30%). Gum Out All in One Fuel System Cleaner + Ethanol Treatment reports a PEA concentration of 3 to 7%. The product has a good reputation on-line.
Do not exceed concentration recommendations.
Note that any PEA is being immediately diluted when added to the fuel tank. So strictly speaking the concentration level in the bottle is not that important seeing how the volume of fuel treatment/injector cleaners can be increased or decreased.
Fuel tank sizes vary widely so there are relatively few useful rules of thumb. Fuel tank information is important; look it up. Follow manufacturer recommendations.
Fuel additives may not be required if constantly using Top Tier gasoline.
Option: Some who regularly fill up on discount brand gasoline, could add small amounts of PEA fuel additive every fill up though adding some every forth fill up might be sufficient.
Technically Advanced Option: Pull and examine the condition of the spark plugs. They should be dry and exhibit brown or grayish-tan deposits. Oil deposits on the plugs likely point to oil leaking into the cylinders.
Short jaunts only
If the vehicle is frequently driven short distances, the motor never gets a chance to fully heat up and boil off condensation. This can be partially resolved by occasionally taking the Soul out onto the highway and driving more aggressively at high speeds, the infamous "Italian Tuneup".
I am jealous so I will rename it the "Canadian Tuneup". Canadian Tuneups are popular with many experienced mechanics, auto technicians (modern mechanics with almost the equivalent of a university degree) and do-it-yourself wrenchers. Drive in a lower gear if you want to avoid exceeding the speed limit.
If only driven short distances, intake valve cleaning should perhaps start before the first oil change. Shorter oil-change intervals should also help. For severe driving conditions such as short jaunts only with no highway travel, the oil change interval should be shortened to as little as 5,000 km or 3,000 miles. Kia recommends that the oil be changed every 6000 km or 3,750 miles under severe usage conditions.
For serious oil loss
If the vehicle is already experiencing noticeable oil loss between oil changes, consider more frequent, perhaps monthly fuel treatment and intake valve cleanings as well as reducing the oil change interval.
If there is a serious oil loss problem that appears not to be correcting with the above methods, a few more radical methods are available: 1) BG Air Intake & Valve cleaning, 2) piston soak, and 3) walnut blasting.
The BG Air Intake & Valve Service and walnut blasting of the intake valves must be performed by a qualified shop, and in most cases that shop will be a Kia dealership.
The BG Air Intake & Valve Cleaner service appears to be a cost-effective option compared to continued oil loss, higher emissions and substandard performance. A more comprehensive BG Fuel System Service is also offered that includes intake valve cleaning and cleans the air throttle body and plenum, fuel injectors and the combustion chamber.
Kia dealerships in the USA charge roughly $140 for a treatment. Downtown Kia in Vancouver, British Columbia offers the service for C$179.95. (early 2021)
Anecdotal evidence suggests that the treatment is most worthwhile.
Pro-active maintenance
Kia auto technician bwdz75 uses this induction/carbon cleaning service every 30,000 miles (~48,000 km) on the two GDI engine vehicles he personally owns (Kia and Mazda).
A piston soak can be performed by a lay mechanic willing to acquire the right tools and chemicals. A piston soak seeks to clean the piston rings/oil control rings. Here is a video that might help: How to Clean Piston Rings Or Oil control rings after head Gasket failure / CCV Failure On Any Car.
The author of the video recommends a British product that may not be easy to find in North America. One can easily substitute with popular fuel injector cleaners mentioned above. Other products such as Sea Foam and even Lacquer thinner have been reported to work.
Less frequent maintenance
► Emission system components should be occasionally inspected and either cleaned or replaced.
The PCV valve is easy to remove and inspect. PCV refers to positive crankcase ventilation. It can be cleaned with degreaser, throttle body cleaner or brake cleaner and then blown out with pressurized air. Or it can be inexpensively replaced with an OEM part from the Kia dealership. Perhaps do this once every 40 to 50 thousand miles / 64 to 80 thousand kilometers.
Option: some enthusiasts replace the PCV valve with an oil catch can.
► Infrequently, clean the air throttle body intake and valve with throttle body cleaner, a soft cloth and a tooth brush. This will help the engine idle and accelerate smoothly as well as reduce carbon deposits.
Dealership or other qualified mechanical shop maintenance
For background reading
TOP TIER™ Detergent Gasoline Brands
Kia Soul: Maintenance under severe usage conditions
Kia letter to US owners of 2012 to 2019 Souls dated 31 July 2020 regarding maintenance
AAA FUEL QUALITY RESEARCH: Proprietary research into the effectiveness of fuel additive packages in commercially-available gasoline
Latest Oil Categories API Introduces Three New Gasoline Engine Oil Standards, ILSAC GF-6A, GF-6B, And API SP
and viewing
compiled and written by westslope with valuable input from GeekOnTheHill, GeoSoul and SportsterDoc
Gasoline Direct Injection (GDI) engines can be more efficient than multiport injection (MPI) engines but require more pro-active maintenance as the intake valves in the GDI engines are not washed in fuel and can carbon up. Increased oil loss signals problems that could lead to increased operating costs, lower fuel efficiency, more polluting emissions, and in the worst case scenario catastrophic engine failure.
Here are a couple of pictures of intake valves. The first is from an MPI engine, the second is from a GDI engine. The intake valve is noticeably dirtier in the second photo. h/t bwdz75
This thread outlines a maintenance schedule that should prevent or solve problems and keep your Kia Soul GDI engine operating smoothly for years to come. It is primarily aimed at do-it-yourself mechanics but also contains suggestions on how to best use the dealership or qualified independent mechanic.
Strict minimum must do maintenance
- Check the oil level often between oil changes. Once or twice a month when the engine is cold.
- Make sure the oil level is full but not overfilled.
- Change your oil and oil filter on time.
- Err on the side of shorter oil change intervals.
- Check the oil level shortly after an oil change. And then check it a week later.
- Use full synthetic motor oil.
Best practice maintenance suggestions
- Use top quality synthetic oil rated at GF-6A and API SP.
- Although top quality synthetic oil can last much longer than standard synthetic oils, oil changes on GDI engines should be kept to shorter intervals. Many advise changing the oil frequently, at intervals not exceeding 8,000 km or 5,000 miles. Kia recommends changing oil and filter every 12,000 km or 7,500 miles under ideal driving conditions.
- Many council switching to 5W30 synthetic oil after the break-in period to forestall deposit build up that can later lead to oil loss. Switch immediately to the heavier grade 5W30 oil if oil loss is or becomes a problem. A few of us still use 5W20 synthetic oil with success but remain vigilant. Both grades were originally recommended by Kia but in recent years Kia seems to have evolved to recommending only the 5W30 grade. 10W30 would also work in warmer climes.
- Use Top Tier brand name, detergent-rich gasoline. If not available in your region, consider frequent fuel treatments (see below under Do it yourself treatments).
Synthetic oil suggestions
Synthetic oils have continuously improved over the years in ways that reduce engine wear, in particular timing chain wear, reduce oxidation and deposits, help prevent low-speed preignition (LSPI) problems in turbocharged gasoline GDI engines, and so on.
Popular brands of oil rated GF-6A and API SP are Pennzoil Platinum, Mobil 1, Castrol Edge Advanced and a promising new oil from Valvoline. Valvoline Restore and Protect.
Extended oil change interval varieties of motor oil can last 24,000 km / 15,000 miles and even longer in some multiport engines. They cost a little more. Examples: Pennzoil Ultra Platinum, Mobil 1 Extended Performance, Castrol Edge Extended Performance. Some of us shop them on sale but still stick to short oil change intervals.
The Kia dealerships sell a box of oil filters that are good, inexpensive and protect the warranty.
Do it yourself treatments
Two treatments are popular. They can be performed a week or month prior to regular, scheduled oil changes, or every few months depending on the condition of the engine and available fuel quality:
Intake valves
Clean out the intake valves with a spray can such as CRC GDI IVD Intake Valve and Turbo cleaner, Berryman Intake Valve and Combustion System Cleaner or Lucas Deep Clean GDI. This procedure works better with two persons but may be insufficient for vehicles already suffering significant oil loss. For serious oil loss, see below.
Fuel additives
Add a bottle of fuel additive which will dissolve carbon deposits in the engine and help keep the injectors clean. PEA stands for polyether amines and is a critical component of many fuel additives. Chevron Techron Complete Fuel System Cleaner is popular; Chevron does not currently report the PEA concentration preferring to keep it a 'Trade secret'.
Red Line SI-1 fuel system cleaner also has a high PEA content (25% to 30%). Gum Out All in One Fuel System Cleaner + Ethanol Treatment reports a PEA concentration of 3 to 7%. The product has a good reputation on-line.
Do not exceed concentration recommendations.
Note that any PEA is being immediately diluted when added to the fuel tank. So strictly speaking the concentration level in the bottle is not that important seeing how the volume of fuel treatment/injector cleaners can be increased or decreased.
Fuel tank sizes vary widely so there are relatively few useful rules of thumb. Fuel tank information is important; look it up. Follow manufacturer recommendations.
Fuel additives may not be required if constantly using Top Tier gasoline.
Option: Some who regularly fill up on discount brand gasoline, could add small amounts of PEA fuel additive every fill up though adding some every forth fill up might be sufficient.
Technically Advanced Option: Pull and examine the condition of the spark plugs. They should be dry and exhibit brown or grayish-tan deposits. Oil deposits on the plugs likely point to oil leaking into the cylinders.
Short jaunts only
If the vehicle is frequently driven short distances, the motor never gets a chance to fully heat up and boil off condensation. This can be partially resolved by occasionally taking the Soul out onto the highway and driving more aggressively at high speeds, the infamous "Italian Tuneup".
I am jealous so I will rename it the "Canadian Tuneup". Canadian Tuneups are popular with many experienced mechanics, auto technicians (modern mechanics with almost the equivalent of a university degree) and do-it-yourself wrenchers. Drive in a lower gear if you want to avoid exceeding the speed limit.
If only driven short distances, intake valve cleaning should perhaps start before the first oil change. Shorter oil-change intervals should also help. For severe driving conditions such as short jaunts only with no highway travel, the oil change interval should be shortened to as little as 5,000 km or 3,000 miles. Kia recommends that the oil be changed every 6000 km or 3,750 miles under severe usage conditions.
For serious oil loss
If the vehicle is already experiencing noticeable oil loss between oil changes, consider more frequent, perhaps monthly fuel treatment and intake valve cleanings as well as reducing the oil change interval.
If there is a serious oil loss problem that appears not to be correcting with the above methods, a few more radical methods are available: 1) BG Air Intake & Valve cleaning, 2) piston soak, and 3) walnut blasting.
The BG Air Intake & Valve Service and walnut blasting of the intake valves must be performed by a qualified shop, and in most cases that shop will be a Kia dealership.
The BG Air Intake & Valve Cleaner service appears to be a cost-effective option compared to continued oil loss, higher emissions and substandard performance. A more comprehensive BG Fuel System Service is also offered that includes intake valve cleaning and cleans the air throttle body and plenum, fuel injectors and the combustion chamber.
Kia dealerships in the USA charge roughly $140 for a treatment. Downtown Kia in Vancouver, British Columbia offers the service for C$179.95. (early 2021)
Anecdotal evidence suggests that the treatment is most worthwhile.
Pro-active maintenance
Kia auto technician bwdz75 uses this induction/carbon cleaning service every 30,000 miles (~48,000 km) on the two GDI engine vehicles he personally owns (Kia and Mazda).
A piston soak can be performed by a lay mechanic willing to acquire the right tools and chemicals. A piston soak seeks to clean the piston rings/oil control rings. Here is a video that might help: How to Clean Piston Rings Or Oil control rings after head Gasket failure / CCV Failure On Any Car.
The author of the video recommends a British product that may not be easy to find in North America. One can easily substitute with popular fuel injector cleaners mentioned above. Other products such as Sea Foam and even Lacquer thinner have been reported to work.
Less frequent maintenance
► Emission system components should be occasionally inspected and either cleaned or replaced.
The PCV valve is easy to remove and inspect. PCV refers to positive crankcase ventilation. It can be cleaned with degreaser, throttle body cleaner or brake cleaner and then blown out with pressurized air. Or it can be inexpensively replaced with an OEM part from the Kia dealership. Perhaps do this once every 40 to 50 thousand miles / 64 to 80 thousand kilometers.
Option: some enthusiasts replace the PCV valve with an oil catch can.
► Infrequently, clean the air throttle body intake and valve with throttle body cleaner, a soft cloth and a tooth brush. This will help the engine idle and accelerate smoothly as well as reduce carbon deposits.
Dealership or other qualified mechanical shop maintenance
- You can either ask for top quality synthetic motor oil or supply it yourself (but ask the shop first).
- Check the oil level immediately after you leave the shop. Then check it a few days later. Look where the vehicle is parked for any signs of oil leaks.
- Many of us shy away from quick oil change shops but if you use one, please note that actually seeing new clean oil on the dipstick under fluorescent lighting can be difficult. Make sure the quick oil change shop does not overfill the motor oil.
For background reading
TOP TIER™ Detergent Gasoline Brands
Kia Soul: Maintenance under severe usage conditions
Kia letter to US owners of 2012 to 2019 Souls dated 31 July 2020 regarding maintenance
AAA FUEL QUALITY RESEARCH: Proprietary research into the effectiveness of fuel additive packages in commercially-available gasoline
Latest Oil Categories API Introduces Three New Gasoline Engine Oil Standards, ILSAC GF-6A, GF-6B, And API SP
and viewing
