Can i use reg oil after using sny blend - 2006 Hyundai Sonata

Castrol 5W30 Synthetic Blend. Do not use full Synthetic, always use synthetic Blend, Full synthetic may not be compatible with engine seals and could result in oil leakage

I would check with an oil/lube co on this issue.I personally would not.Sometimes when you change blends a vehicle will start burning oil.

ENGINE OIL

You will need to use a 10W-30 grade engine oil, such as any of the following Mobil products.
"Fully synthetic" oils are more expensive. Conventional oils or syn blend engine oils are fine for the vehicle but need to be changed more frequently.

Mobil 1 Extended Performance 10W-30
fully synthetic motor oil ;
Mobil 1 High Mileage 10W-30
fully synthetic motor oil;
Mobil 1 10W-30
fully synthetic motor oil;



Mobil Clean 7500 10W-30
synthetic blend motor oil ;
Mobil Clean High Mileage 10W-30
a conventional motor oil;
Mobil Clean 5000 10W-30
a conventional motor oil .

I like to say that sysnthic oil is great but engines that are oil enought to have built up deposits from the ordinary oil these deposits can turn hard and scratch up the motor if the engine is near new or newly rebuilt nothing but pu the oil in and go. if it's older you can get benifits from the blended oils. As for longer change intervals the oil it'self may be OK but engine wear and tuning problems can get contanimants in the oil and the oil will need to be changed to get them out. so the ecomomy of the better oil and longer change intervals willbeovercomed by the added drit so often changs=es with ecomony oil may be cheaper and better. If the oil stays clear for a long time the full sysnthinic and longer change times may be the way to go. The higher price of the full synthic oils and then chnge it less often than the difference in price may be too long and therfore no savings

It will be on the cap you fill it with oil. (Probably 5w-30)

You can use either a full synthetic blend oil 5W30 or 5W40, and even a semi synthetic blend oil 10W40.
If you have the last invoice for service , it should state which grade of oil was used, or you can check under the bonnet to see if they put a service sticker or tag , showing which oil they used.
Hope this helps

Long story short, on oil, they all work.

Use exactly what is specified on the oil fil cap, or the owners manual, ESPECIALLY the weight (5w 20 wt for example).

If your question was asking about synthetic, that answer depends on how much oil the engine consumes. Synthetic is not forgiving and will make consumption worse. If you can use synthetic, that has to be better.

One other option is syntehtic blend. These are typically high mileage oils, Caster oil makes one...It uses a blend of regular and synthetic, and also helps lower consumption.

Doc

what I would try first is replace the oil pump. you say you're not getting oil to your lifters. no oil pressure is a sign of bad oil pump. I had a ford fairmont do the same thing, and once I replaced the oil pump; put a WIX oil filter on. and used a blended(syn and reg) oil, it fixed it. don't start anymore until you've done this.

The VW specs for oil is way over-hyped.

Use a Brand Name Full Synthetic 10W40 oil and you'll be OK.

The motor oil from the factory is motocraft synthetic blend 5w-30 for normal conditions and motocraft synthetic blend 5w-20 for cold environments. But any synthetic blend or full synthetic of equal weight will do just fine and you will require 5 quarts of oil. DO NOT USE A THICKER WEIGHT OIL, OIL ADDITIVES OR NON SYNTHETIC. Thicker oil like 10w-30, 10w-40, 20w-50 will not be thin enough to lubericate the tighter clearences of the motor and coventional oil breaks down faster than a synthetic blend or synthetic. And be sure to change the oil every 5,000 miles