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We have a local radio station here that a master mechanic has a 2 hour call-in show every week and he was just going nuts this weekend, that manufacturers (not just KIA) use 5-20w oil instead of 0-30w. He says that 20w oil is just too thin for us southern folks, while 0w gets to the engine quicker on cold start up. My dealer says that they use 5-20 "blend".
Note that the oil grades are properly written as 5W-20 and 0W-30, where the W part refers to the viscosity rating at or near start-up temperature, and the other part is the viscosity rating at operating temperature (100°C).
There is a tendency to advocate 20-grade oils in the interests of fuel economy, but many people (including myself) consider them "too thin". The problem is, 20-grade covers a wide range of viscosities (5.6 to 9.3 cSt), and some brands may in fact be "too thin", especially when they've been in service for a few thousand miles and have degraded somewhat.
KIA Australia recommends 10W-30 for many of its cars, and especially in the "Deep North" where I live, it seems to be the right choice. I use 10W-30 in the KIA and 5W-30 synthetic in my other car. These 30-grades have a working viscosity of about 10.2 cSt - just a bit lower and you could call them 20-grade.
A 5W-20 "blend" probably means synthetic/conventional mixture. Dealers are often misinformed about oil, and are usually tied to using whatever the dealership gets in bulk. One service department (non-KIA) told me that I needed 40-grade because our temperatures often get up to 40°C.
Don't know what to think. Either you are not as sensitive to the noise, or I am over sensitive to it, or...some KIA engines (both 4 & 6 cy) have it and others don't. I do not hear it as much when in the car during start up, but when the wife starts it up and we are in the garage, I just cringe.
We have a local radio station here that a master mechanic has a 2 hour call in show every week and he was just going nuts this weekend, that manufacturers (not just KIA) use 5-20w oil instead of 0-30w. He says that 20w oil is just to thin for us southern folks, while 0w gets to the engine quicker on cold start up. My dealer says that they use 5-20 "blend".
Dunno what to tell ya. After 3500 miles, I bounced the factory fill and only use Pennzoil Ultra 5W-20 full synthetic. I've never heard any rattle.
I only heard a slight rattle a couple of times when the car was new.
You could experiment with different oils and listen for any improvement. The 0W-20 oils might flow more easily at start-up, but they might also drain more quickly when you stop the engine, leaving less oil behind to help things along next time. Castrol "Magnatech" oils are supposed to take advantage of this principle at start-up. e.g. Castrol Magnatech 10W-40.
I am attracted to 10W-30 for general use because of the lower amount of viscosity improvers and this would tend to make the oil more stable. e.g. Caltex 10W-30.
Various KIA dealers recommend different brands of oil. I'm sticking with the most recent recommendation (10W-30 Caltex), and will do so once it's out of warranty. One of my other cars is still in warranty and the dealer doesn't mind if I supply my own oil.
Some oils damp noise better than other oils. It has nothing to do with the oils quality, i. e. the oil's protection of the engine. Try a different brand of oil next time you do an oil change.
There is always a lot of discussion about the oil viscosity. First, the "W" winter viscosity is measured at very low temperatures...-35°C for 0W, -30°C for 5W, -25°C for 10 W. These are all part of the SAE J300 spec. The other viscosity number is measured at 100°C. It is important to match the viscosity of the oil to the temperatures actually inside the engine at the bearings, not the water temperature. In very hot weather, especially if the car is driven hard, it might be prudent to go up to 30 wt. The film strength of the oil, other things remaining equal, relates to the viscosity of the oil. If the bearings are of adequate size, then lighter oil is fine--the load on the bearing is spread over a large enough surface area so the the force is spread and the oil film remains intact. Keep in mind that a 747 jet engine uses oil of about 5 wt. Kia warrantees our engines for 100,000 miles if you use a 5W-20 oil and change it on schedule. I'm just guessing that they know more about the engines than we do.... Even a very large diesel engine putting out 7,500 hp per cylinder only uses a 30 wt crankcase oil. In general the viscosity used won't make any difference. I wouldn't use 10W-30 in a northern Canadian winter, and I'd be loathe to use a 5W-20 in the hottest parts of Oz or Death Valley. Caltex is a Chevron brand and good stuff.
Blend, schmlend. Some synthetic base oil can be mixed into the conventional base oil for a couple of reasons. Really cheap conventional oil can be used and add some cheap so-called syn, the whole mixture now comes up to spec, and it can be marketed as something special...synthetic blend oil. Or, a top syn can be mixed with a top conventional oil to improve the mixture and make an excellent oil. Yes, there are synthetic oils of varying qualities. Some are little better than the best conventional oil and not worth any extra price.
In very hot weather, especially if the car is driven hard, it might be prudent to go up to 30 wt. The film strength of the oil, other things remaining equal, relates to the viscosity of the oil. If the bearings are of adequate size, then lighter oil is fine -the load on the bearing is spread over a large enough surface area so the the force is spread and the oil film remains intact.
I wouldn't use 10W-30 in a northern Canadian winter, and I'd be loathe to use a 5W-20 in the hottest parts of Oz or Death Valley.
I think we are generally reading from the same song-sheet. Most manufacturers give charts for oil grades and expected ambient temperatures. Also some engines have oil-coolers to keep things under control in high-performance situations.
BTW, Australian extreme temps range from -20°C to +50°C, but mostly it's +5°C to +35°C.
Good to hear that it's improving. If it was a "bad" noise it wouldn't improve.
You'll always get quite a response when the subject of oil comes up. Some of the information is useful, but very little is based on subjective testing. Use the correct grade (or something close!) from a reputable company and change on a regular basis. Try looking at BITOG; too much info on oil is never enough!
I use Castrol oils because I've been using them for a long time, picking the varieties that have evolved over the years. For the price (about $40 per 5 litres), they seem to do a good job, and I've never had an engine failure. Castrol Synthetic is about $75 per 5 litres, so look to buy it on special.
Caltex (Havoline) was recommended by the KIA dealer that my son went to for service, so we're sticking with that. Apparently it has a good reputation. Only available at service stations, not Auto Marts.
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