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Engine Sludge and what to do

Hello to all, I’m new here and my question concerns my 2012 Hyundai Sonata. I purchased the car in January 2014 as a certified pre owned vehicle with 66,496 miles. In the 2 years I’ve owned the car I’ve driven under 12,000 miles with 2 oil changes. Mileage now at 77,840. The problem is on Christmas day 12/25 I noticed for a split second the oil light came on and went out when I was making a left turn. I pulled into a gas station to check the oil and observed no visible oil on the stick. I then sat with the engine off for 30 minutes and checked the oil level again. This time there was oil on the stick but only on the tip. I did not see any signs of a visible oil leak so I added 2 quarts that day. I just recently had the oil changed at Hyundai on 11/19 so I was concerned they had not done something right while servicing my car. I took my car back to Hyundai yesterday and the service guy told me the engine has sludge and they would need to preform an oil consumption test to determine the extent of the problem. He also researched the vehicles history reports and found the original owner purchased the vehicle from the that particular dealer. The car was brought in for an oil change and service at 5000 miles, then brought back in at 22000 miles and then they did not see the vehicle again until 42000 miles. While Hyundai has no way to know if the previous owner was getting regular oil changes and can’t say for sure what has caused engine sludge build up, they have informed me the engine does have sludge. I’ve done some research and have found opinions differ on what can be done. From replacing the long block to disassembling the engine and cleaning it with harsh solvents to engine cleaning additives. It is frustrating to me, in a time with so much information on hand there is also just as much as disinformation and varying opinions. I still owe $10K on the car and don’t have a lot of money to pump into the repair. I have an extended warranty but it’s not going to cover replacing the engine block due to engine sludge build up.
Here is my question; What are my options to extend the life of this car for 2 possibly 3 more years? My driving habits are local driving only around my home town here in Florida. As stated previously I’ve put less than 12,000 miles on the car in 2 years. I understand driving a car for short periods can cause engine sludge to build up. While I do occasionally drive it to the store less than 2 miles, most of my driving consists of between 4 to 60 miles round trip. I drive a company vehicle for work so the Sonata sits parked for days at a time. Thank you for taking the time to read my post. Sincerely Macy in Florida

First off, you PAID for the extended warranty to address exactly these kinds of issues. It wasn’t your fault that the previous owner didn’t get enough oil changes. If you have proof that you did oil changes on time while you owned the car, I’d talk to a lawyer that specializes to these type issues. You could argue the case with the warranty company yourself but a lawyer doing it applies more leverage. It could be the best money you ever spent.

That said, the engine oil consumption is a problem that may not be due to sludge buildup. But that is the excuse used to avoid the warranty paying for the problem. I would have the dealer use an engine oil flush additive and change the oil, but use a full synthetic oil “for high mileage cars”.

In my experience, it has so many detergents in the oil, it tends to flush out the sludge. Check the oil EVERY time you add gas and carry a quart or 2 of the synthetic you put in. Change the oil again in 1500 miles making sure you get the engine fully warmed up before taking it in for the change. Use synthetic again and run it for 3000 miles taking note about how quickly the oil on the dipstick gets again and how much extra oil you use in that 3000 miles. If it uses a quart in less than about 1000 miles, its time to go back to the lawyer to go after the warranty company.

Good Luck, post back with what you find.

If your engine has sludge build up, it does not need a complete disassembly to clean it up. I say if because they cannot tell if there is a sludge build up without removing the valve covers and it doesn’t sound like they did that.

For the most part, sludge build up is harmless. It mostly accumulates under the valve covers on top of the head. It becomes a problem when it clogs the return passages and I suspect that my be the issue in your situation. When this happens, oil accumulates under the valve covers because it can’t drain back as fast as it is being pumped up there.

If oil accumulates under the valve covers, it can get high enough to be sucked down into the combustion chambers around the valve stems and valve stem seals so you have some oil consumption issues. It can also lower the oil level in the oil pan to the point where the pick up tube is not under oil, particularly in a turn.

The quick fix is to take off the valve covers and remove as much sludge from the top of the head as possible. Then use a large screwdriver to clean out the return passages so that oil can freely return to the pan. This will result in chunks of sludge getting into the pan so an oil change is needed, along with new valve cover gaskets.

Do a second oil change in the next 500 to 1000 miles and possibly a third in the same interval. No need for a synthetic oil for these. After that monitor the oil closely keeping the engine full as needed and change the oil when it gets really black, or at its normal recommended interval, which ever occurs first.

If you have the 4 cyl engine, you should Google “Sonata engine recall”. and read this article

What I’d do in this situation – presuming the only symptom was that the oil was discovered low on the dip stick – is just change the oil and filter every 2000 miles for a while. It could clear things up just by doing that. Make sure to use the exact oil spec’d in the owners manual. I’d probably use an OEM filter bought from a dealership. If you are having a shop do these changes, be sure to check the oil on the dipstick immediately after the change before leaving the shop, and again the next morning, before starting the car.

Oil consumption as much as one quart every 750 miles is considered normal for many newer cars. This is b/c to get the needed mpg to meet EPA fuel mileage fleet requirements the engine is designed to use low viscosity oil. It’s good for mpg, but tends to leak into the engine cylinders and burn away faster. So you pretty much have to check the oil at least that frequently, and top off if it is down a quart between changes, even with brand new cars. That’s just the way it is with newer cars.

Depending on how much sludge - you may need to disassemble the engine to fix it. Sludge can be very bad for the engine. It starts forming at the top end of the engine…but also forms/settles in the pan. This can end up clogging the oil screen and starve the engine of oil.

If sludge buildup has just started then changing the oil regularly with good oil and filter can clean it out. You can substitute a quart of oil with a quart of Rislone every oil change. Rislone does a great job at disolving sludge. I would NOT recommend using Rislone for heavily sludged up engines…it can cause large chunks of sludge to break away and that can destroy an engine.

Thank you to all of you. You all obviously have a lot of automotive knowledge and the information you have given me will be of great help when dealing with the service guy at Hyundai. To Mustangman, I really appreciate your advice about talking with a lawyer about my extended warranty. edb 1961, You are the man. I’ve printed out that article and I’m taking that with me to the dealer. I’m keeping my fingers crossed. Thank you! The service guy at Hyundai tells me, he’s submitted a PO to Hyundai motors explaining the details of my situation and that he feels positive that Hyundai Motors is going to work with me on fixing this problem. I’ll find out what that result is later today. Again thanks so much to all of you. Sincerely Macy in Florida

“he feels positive that Hyundai Motors is going to work with me on fixing this problem”

I would certainly hope so.
Otherwise…what is the supposed benefit of paying extra for a used car that is “certified”?

Normally, when somebody buys a used car, he/she bears the effect of the maintenance habits of the previous owner(s), whether those habits were good or bad. However, in this case, since it is a “certified” used car, the manufacturer or the dealership should be responsible for this remedy to the sludge situation.

Was this a mfr certified used car, or is it merely certified by the dealership?
Either way, whichever entity certified that it was in tip-top condition should be the party that pays for the repair costs.

They are doing you a favor by trying to replace the engine under the oil consumption warranty.

If authorization for a replacement engine is submitted under the service contract, an inspector will likely be sent to inspect and take pictures of your vehicle and engine and sludge is usually an indication of poor maintenance. Next will be oil change receipts during the time you owned the vehicle and 2 is not enough. The oil should be changed every 7,500 miles or 6 months under the normal driving conditions schedule.

To every one who has offered me so much advice. You have all been of great help thank you! Hyundai has informed me they are going to replace the entire engine for free. Again, thanks to all.

Good news @Macy_Fl_16!

Thank you for posting the results of your action. We always like to hear the good outcomes as well as the not-so-good.

It is nice to hear that Hyundai is going to do the right thing