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Discussion Starter #1
I have to change my engine oil soon and I am thinking of flushing the engine with Gumout motor flush. The reason I want to flush is because my car has extreme high mileage over 300,000 miles and I guess it might have lots of sludge inside the engine. Is the engine flush safe and worthwhile?
 

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Somewhere in this video, they do an engine flush, and it seems successful. On such a high mileage motor, I would seafoam it, and use a motor flush. They say seafoam could be bad for the cats though because high amounts of carbon might clog them up.
 

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i was told that motor flush is best for regular use on keeping an engine clean. the problem with high mileage is that the sludge will fall out and clog elsewhere. the proper way is to open it up and clean it all out by hand.
if its high mileage but has regular oil changes, then it shouldnt be too gunked up anyway. it is 300k miles, so maybe. but im betting it got there with regular oil changes.

also, seafoam works as a motor flush if you put it in the crank case.

and most people i know dont like gummout brand in general. Gunk brand makes a motor flush as well.
 

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Discussion Starter #4 (Edited)
1. Re: Seafoam is bad for cat: I used Seafoam when my Elantra has CEL P0420 code, it cleared up the code. It could be coincidence, but it helped me several times.
2. Re: Sludge will fall out and clog elsewhere: I read about this from other website. This is the risk using motor flush. Too see whether my Elantra really has sludge, someone suggest that I should check under the engine oil filler cap. I checked mine and it was clean. I remember my old Oldsmobile oil filler cap had lots of sludge underneath and I had to clean it often. I didn't know what it was at that time. Last year I opened the valve cover of my Elantra to change the gasket. I looked it up and all the valves and oil were super clean and I didn't see any sludge anywhere. I acknowledge that I used motor flush a few times in the past.
 

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Never flushed, Always run full synth Mobile 1 Extended Performance 5w30 oil and a purolator "one" filter, Changed every 3-4k miles. Needless to say, The inside of my engine looks as close to new as a 225k mile engine should...Maybe better...
 

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Discussion Starter #6
Mobil 1 EP oil is guaranteed to last 15,000 miles. If you changed the oil every 3-4,000 miles, you wasted money and it's bad for the environment.
 

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04 GLS - Low, Slow, Angry
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The filter isn't good for 15k miles, And that 15k mile isnt exactly true. Breakdown depends on how often your car is driven and the other elements.
 

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Only use the OEM Hyundai filter on the elantras (otherwise you get a tick - there is TSB on this). I usually run the Mobil 1 EP oil for 7,000 miles with a change of oil filter in the middle and top off the oil.
 

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Royal purple is good right.? since my car is on 87k-90k miles should I use 10w-30 or 5w-30 whats a good filter to go with it I heard fram sucks

KDM_STANCE_XD2
 

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Discussion Starter #11
5W-30 is for very cold climate down to -20F. I use Mobil 1EP or Microguard synthetic filter.

Of course, I use full synthetic oil. That is my secrete to have 30mpg even after 306, 000 miles.
 

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opening the valve cover is the better way. that and the bottom of the oil pan. on my 06 elantra, under the oil cap had a lot of burnt oil. i was thinkin the previous owner didnt change the oil too frequently the first 30k. but i didnt find any sludge in the engine.

as far as what causes sludge, ive always figured it was neglect and old oil. but i was told that years ago (like, 80s maybe?), you could tell if a car primarily used quaker state by the sludge buildup. quaker state today supposedly fixed that problem.

and i think what he meant by seafoam being bad for the cat, is the same concept of the motor flush. might knock too much loose and get clogged. but even then, it should still clean the cats. it does however, foul out spart plugs, so get ready to change those.
 

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I've never used it on the Elantra, but we used to use it on our cars back in the 80 and 90's. It worked so good that all of the leak-plugging sludge would be removed and you'd wind up leaking oil in places you didnt know got oiled. LOL
 

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Only use the OEM Hyundai filter on the elantras (otherwise you get a tick - there is TSB on this). I usually run the Mobil 1 EP oil for 7,000 miles with a change of oil filter in the middle and top off the oil.
I haven't gotten the tick yet, Been running Purolator One filters since brand new, As well as Mobile 1 EP 5w30 Full synth.


& I don't exactly have "low miles" lmao. 225k on the chassis, 181k on the engine.
 

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I agree with those on here running Mobil 1 full synthetic, I've been changing my oil with the 5w-30 for the last 9,000 miles or so and my engine looks very clean for having 165,000 miles on it. I recently changed my valve cover gasket, when I saw the cams I was surprised. I used to run the gumout and the chevron concentrated techron formula every so often until my old shop teacher told me that stuff ruins your cats over time, he seemed to know his stuff; plus I didn't see any noticeable performance or fuel economy gains with the additives.
 

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Okay so whats a good oil brand to use with a filter so I can use it at my next oil change I dont wanna use royal puprle since its expensive, I wanna use another synthetic oil like mobile 1 EP

KDM_STANCE_XD2
 

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AVOID Quakerstate...I used QHP for 100k, Swapped to Mobile 1 EP and haven't seen any "golden" color to my internals since...I think Quakerstate is alright for the buck, Works like any other oil, I think it may still have some detergent though because it likes to leave behind a heavy film

Sent from AutoGuide.com Free App
 

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So should I start using synthetic mobile 1 EP I wanna keep it nice n clean in the engine not like some other oils who leave engine all sluggish n all black in the inside.? What filter should I use

KDM_STANCE_XD2
 
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