I put synthetic blend in my used 09 focus like about 2 weeks ago. 123k miles. No maintenance history. Driving it daily. The oil on the dipstick still looks clean but from where you put oil in, it looks like there might be sludge build up. Should I go ahead and put a high milage oil with its additives or just keep using synthetic blend? Or upgrade to a non hm full synthetic oil?
Just use the type of oil recommeded in the Ownerâs Manual, and focus on very frequent oil changes in an effort to get some of the sludge out. Ask your mechanic to remove the valve cover in order to determine the extent of the sludging, and see if he recommends flushing the engine to get some sludge out.
What does âHMâ stand for?
High milage. Theres synthetic blend hm oil and full synthetic hm oil. Detergents and additives added to the oil.
If i upgrade, im thinking of going with supertech full synthetic. Really cheap but I wish they had a synthetic blend. They only have conventional.
High mileage oils contain additives designed to reduce oil leakage by softening/swelling the seals. To the best of my knowledge, they donât have a higher detergent content.
When high mileage oil swells the rubber seals, that means itâs starting to dissolve them. It will work for a while, but if you plan to keep this car for a few years, I would just use regular mineral oil and change at least as often as Ford recommends for severe service.
The OP might want to consider using something like this product a few minutes before his next oil change. Please be sure to read all of the info on the following website and on the productâs packaging, and to follow the directions precisely.
https://www.valvolineglobal.com/en-ksa/engine-flush-what-is-it/
It is cold. Happens in winter. That does lead to some scummy stuff on oil fill cap. Could be frequent short trips in cold weather.
You contradict your self, did you mean to say supertech is only available as synthetic, rather than blend?
Full synthetic will not hurt your engine.
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Tester
Iâm confused. Is the oil clean or are you seeing sludge? I seriously doubt that you could see any sludge from the dipstick. At the very least youâd have to pull a valve cover or drop the oil pan.
Iâve never used high mileage oil before. Even on vehicles with well over 300k miles. Never an issue. Some people swear by it and have seen great results. It wonât hurt. But whatâs considered high mileage?
Thatâs not necessarily an indication of sludge. That could be the engine not getting up to proper temps and water is mixing with oil. I see it on many cars.
Tester
No maintenance history? Did you just buy the car? Anyway, a little sludge build up under the cap is normal. Just wipe it off and carry on.
If you can take a flashlight and look down into the oil fill area and see a lot of sludge, then the no maintenance history is an indication that very little maintenance was done.
If the sludge is brownish in color, then some moisture is getting into the engine. This could be nothing or could be a sign of real trouble coming. Mostly it is just the seal on the cap is dirty and allowing some moisture to get into the area, cleaning the seal will solve the problem. Worst case is a blown head gasket or worn out rings. If you have a blown head gasket, you would notice some coolant loss, if you have worn out rings, then you would see significant oil loss, like a quart every 500 miles or less.
Moisture can also get in through the PVC system, usually an easy cheap fix.
If you want a synthetic blend, buy 4 quarts of dino oil and one synthetic. To my mind, semi synthetic has no purpose. They donât tell you the percentage of synthetic and today if you are buying the oil yourself, synthetic is pretty cheap in a 5 qt jug.
I run HM oil on all my vehicles starting at 75K miles, never had an issue, also recommend HM to all my customers with over 75K miles on the engine, in 17 years with the same company, never had an issue through out the company due to using HM oils, nor since I retired in 2021 (I keep in touch lol)âŠ
Now HM oil is not a repair, so if seal blown out or gasket leaking bad, replace itâŠ
I suggest checking the crankcase vent system THOROUGHLY.
Bottom line: use the grade and type (conventional, blend, or synthetic) oil specified in the manual. Itâs that simple. If OP wants to be âniceâ to the engine, no harm in using synthetic and/or HM of the proper grade even if itâs not specified. Iâd use synthetic if cold weather was involved.