High Mileage Oil switch no leaks/consumption

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If you aren't burning any oil or have any leaks is it still a good idea to switch over to a HM oil at 75-80k? Is the main reason it's recommended due to preventive high dosages of seal conditioners so future leaks don't start? I've read/watched conflicting information regarding a lot of previous searches on the topic. A lot of it being old threads that might not apply with new formulations. Is there really a difference between a Seal Sweller & Seal Conditioner?
 
All motor oil contains seal conditioners, the high mileage oils will contain a higher treat rate though, roughly double from my understanding. Yes there's a difference between conditioners and swelling agents.

If you're using high mileage earlier on its preventive maintenance to help keep the seals conditioned before they can get too dirty. Of course you want to make sure it meets all the other requirements your engine needs such as API service classification, which most are now current SN anyway.
 
HM oil won't hurt anything, but it's not really necessary. I was a little different on the company Transit 3.7-I used MaxLife to get a synthetic blend oil (VIOC doesn't use Durablend anymore). But, when Valvoline started making their 5W20 a syn blend (not that I believe a GF-5 oil doesn't have at least a little syn in it), I switched it to VWB 5W20. Still zero consumption, now cranking along at over 61K. Proof that HM oil doesn't cause seal leaks when switched back to regular!
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Good to know you switched back with no issues. I plan on continuing with GTX HM as a preventive measure but possibly switching over to Edge HM since I used Edge 5w20 from around 25k to 75k in the 08 Santa Fe. Castrol Edge from what I've seen in UOA/VOA on here is more like Pennz/QS than it's counterpart GTX on the add packs. I'm sure the GTX HM is capable of getting the job done though. Thanks for feedback appreciate it.
 
I've always received different responses on whether to switch to a HM oil as a preventative measure. The seals you're dealing with are primarily the rear main and valve stem. Valvoline MaxLife was always recommended for new cars too, but I'm not sure what type of seal conditioner they are using. In engine makes that are known to eventually leak, I'd be more likely to use one before it leaks. What I do like about some of the newer HM oils is they meet SN Plus, often reduce oil consumption by minimizing the viscosity spread and contain slightly better detergency.

I like the Mobil 1 HM 5w20 and M1 HM 5w20 EP, both of which have a HT/HS of 2.75 and 2.8 respectively. They also ony have a VI of 150-160. Not a bad choice, especiallly for a fuel diluter.
 
Most HM oils don't meet Dexos spec so if that matters as most think Dexos is a better add pack then you will have to go with Valvoline HM Advanced Synthetic which is also good for new cars.
 
People have used oils where there is no high mileage alternative like Motul or Redline way past the 75k mark no problem. If the care and oil start out good in the very beginning then there might not be a need for HM oil at all for those people.
 
My only experience with a HM oil is that it did more harm than good. My Mustang was burning oil at a rate of about 1 qt/1,000 miles. No idea where it was going at the time, but I fixed the only leak it had from the oil cooler gasket and there were never any drops under it after that but I still had the consumption. Gave MaxLife high mileage a try and within about 300 miles, the consumption actually got worse and it started smoking. The smoke was consistent with valve seals (it didn't smoke at startup like most, but did smoke when taking off after idling at a light for a while, and then stopped smoking until it had another chance to idle, at which point the cycle repeated) so I replaced those, and not only did the smoke go away, but all oil consumption immediately stopped. I guess I have the MaxLife to thank for finally making the problem bad enough that I could identify it, but it certainly didn't fix it.
 
"75,000 miles = high mileage" is total bunk. A well-designed, well-built and well-maintained engine is in the prime of its life at 75k if it isn't abused. Modern oils are excellent and I won't use a HM oil until the engine shows signs of wear: oil consumption, oil leak(s), engine knock when hot, etc. Oil leaks don't always indicate engine wear, often a seal or gasket replacement is needed (although I won't pull the engine to replace one seal LOL). Also, rough idling is not always a sign of engine wear, maybe it needs an injector or TB cleaning, ot some other maintenance item. You get my point.
I guess my one exception would be if I reach 300k miles and no signs of wear, I might switch to HM anyway. We will see...
 
Originally Posted by DGXR
"75,000 miles = high mileage" is total bunk.

I agree and that's why I would use HM oils in a new car off the lot.
 
My brother's old 2001 Toyota developed a rear main seal leak. Mobil 1 HM fixed it. He sold the car years ago and recently ran into the guy that bought it. It has 426,000 miles and still going strong.

It is true that all oils contain seal conditioners. I don't see the point of using one until you maybe start seeing some small leaking, or the car is over 8 years old 100k miles. Another factor is the engine quality. Some engines are just made better with better materials and don't leak much. Most Toyotas don't leak. Other brands seem to leak more. So it's often the engine family as well I think.

The Mobil 1 EP HM 5w20 oil has a VI of 150 and a HT/HS of 2.8. It would probably help reduce consumption in some engines with burn-off issues, but that can also be due to other things like worn rings etc.
 
I have 182k on my 2010 Sebring and still don't use HM oil. I also go 6k between oil changes and the level never drops more than 1/2 qt from full. If you're not seeing any ill effects from the mileage, then really no need to switch to an HM oil.

L8R,
Matt
 
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