Car question: Synthetic vs conventional motor oil

[chunglii]

My 2005 Hyundai is low on oil so I need to put more in. I go to the auto parts store and am about to buy a quart of oil then realize it might make a difference if I top off the oil with one type when the other is already in the car. I ask an employee at the store and he tells me it makes a huge difference and could damage the car. Unable to remember if the service station that changed my oil put synthetic or conventional oil in my car, I left without buying anything, not wanting to risk hurting my car.

however, everything on the Internet I've seen says mixing the 2 types of oils will NOT hurt my car. So, what say you, car guys of Mayberry? If my car has synthetic oil in it already, would topping it off with conventional make a difference? Or vice versa? And if the dude at the auto parts store was incorrect, why would he give me a bullshit answer?

 

[Xplosives]

just drain the oil and then fill it up fully if your concerned.

 

[jefferz]

You're fine, just make sure you use the same weight.
As for the auto parts salesman he wanted to sell you oil and a filter.
Biggest issue is why your car was a quart low, fix that immediately.

 

[Adamant]

Personally, I would just drain the existing oil out completely, chance the oil filter, and fill it up with 100% full synthetic. Just make sure to get the proper weight for your car.

Also, I would have the thing checked for leaks. Wouldn't hurt.

As for brands of oil, go with Pennzoil Ultra Platinum. Can't go wrong with that. It has a reputation for being the best on the market.

For filters, I like BOSCH Distance Plus. It holds the most dirt and crap of any filter on the market.

These two together, I can run my car for 15,000 miles between oil changes (have actually done it multiple times) and the thing runs just fine. No problems whatsoever.

Good luck.

 

[emefer]

You should be using Wesson. F the auto parts store. Just go to the supermarket.

 

[ramsiN]

do not mix synthetic with normal oil. im more then sure whoever changed your oil used regular crap motor oil, you should know when they use synthetic cuz they charge you like $55+.

if you dont want to use synthetic, just buy "High Mileage." if you are looking for a thicker oil that can hopefully somehow plug the hole even if a lil bit, then "High Mileage" or synthetic is what you need. they are thicker oil blends, High Mileage oil is actually used for obviously high mileage cars because the engine supposedly develops leaks over time and this thicker blend supposedly helps with plugging up leaks. but if you got a stripped oil pan or a hole in it you're fucked and thicker oil wont really help, a new oil pan only will. if you have stripped threads on the oil pan you can always have them re-threaded, but its only a temporary solution and when compared to changing the actual oil pans price it really doesn't make much financial sense, but it also depends on your car.

 

[chunglii]

I know the best option for me would be to drain the oil myself and put 100% synthetic in, which I'm sure even with my limited car skills I could do sometime soon but if I buy a quart of synthetic oil and top off my car will it be fine?

 

[jefferz]

Yes

 

[SwtTeaStrangler]

How close are you to needing an oil change?

Don't mix oils. Not good for the car.

 

[thetruth2709]

dude you can tell if it was synthetic or conventional by how much you paid... Im sure the difference of how much they charge in those places is very noticeable

 

[emefer]

I believe pennzoil platinum full synthetic is fine to mix with any other type of oil but with the price of oil just change it and throw on a new filter and do it yourself, takes a whole half hour and that's with drinking some beers.

 

[Adamant]

I know the best option for me would be to drain the oil myself and put 100% synthetic in, which I'm sure even with my limited car skills I could do sometime soon but if I buy a quart of synthetic oil and top off my car will it be fine?

Yes, that would be fine. But you're not fixing the problem. It'll get low again.

Don't mix oils.

But you can also buy the new oil and oil filter and then take them into the car shop and tell them you want them to use your stuff. They'll change it out and give you a discount. Walmart does this for sure.

 

[Stump]

Don't mix oils. Definitely don't mix synthetic and conventional.

Drain all the oil out, buy a brand new filter and fill the bitch right back up with brand new synthetic oil. Problem solved.

 

[lts5025]

There's a reason why the guy is working a counter at an auto parts store instead of fixing cars for a living. As for mixing conventional and synthetic oils together? You should never do that, I mean it's not like there are oils on the shelf at the auto parts store that are already blends of synthetic and conventional, right?

Oh, wait...

Spoiler

 

[Michaelangelo]

I doubt you have synthetic. They normally use that oil for Mercedes and BMW. It costs about a 100 bucks for a synthetic change.

Vs a regular at 20 bucks.

 

[philth]

I mean it's not like there are oils on the shelf at the auto parts store that are already blends of synthetic and conventional, right?

Oh, wait...

Spoiler

This.

Mixing synth and dino will not hurt anything.

Mixing weights on the other hand, could potentially cause long-term damage. I don't think it's actually been proven without a doubt though.

Synth is a better oil overall though. There are always deals on synth at places like walmart or whatever - pick yourself up a bottle and new filter (try to steer clear of Fram oil filters) and do the change yourself. You'll save money, get to know your car, and feel like a 'man' doing it.

brand of OIL DOES MATTER FOR YOUR CAR - just make sure its FULLY synth and the proper weight for your engine - brand of filter matters.

 

[Goodfoot]

Its fine to mix synthetic and conventional oils
http://chemistry.about.com/b/2013/07/17/what-happens-if-you-mix-regular-and-synthetic-oil.htm
Just don't make a habit out of it due to possible additives from different manufacturers reacting to each other badly.

 

[jefferz]

Don't mix oils. Definitely don't mix synthetic and conventional.

Drain all the oil out, buy a brand new filter and fill the bitch right back up with brand new synthetic oil. Problem solved.

Mixing it won't hurt anything. I'm staring at a shelf full of oil at work and there's at least 6 synthetic blends.

 

[genki sugoi]

I'm 99% sure you don't need synthetic in your 05 Hyundai. Any SAE oil should be fine. The only benefit you would get from synthetic is being able to go longer without an oil change. All the people who say don't mix synthetic and dyno I guess have never heard of synthetic blends which are the 2 mixed. My auto shop teacher always said it's better to have the wrong kind of oil (SAE approved) in than running low. So I follow that rule.

 

[BigJaw McCarthy]

Why not just call the quik lube place that changed the oil to find out what they put in? Most keep fairly detailed records on what they do to cars that come in. They'd be more than happy to let you know.

In my worthless opinion as a former grease monkey and gearhead, I don't think mixing dino/syn or weights matter (within reason) unless the car sits for a long time right after mixing oils (like months) and possible unknown chemical compounds are created and counteract each oils viscosity, eat bearings, etc....basically like a petri dish. But that doesn't happen overnight; its not like oil and water. And damn sure not while the crankcase is slushing around under pressure while driving everyday.