I have no idea what the previous owner used I. My corolla (mostly local garages all over the state depending on where he was working). I got the car with 180k and put synthetic in. I have no leaks.

The leaks tend to be more of an issue with old motors and crappy gaskets, I would throw synthetic it. If you notice weeping then go back to conventional.

 

I won't tell you what to do, but I'll relate my experience and opinion.

I bought the '08 CE model new. I used 5-30 conventional oil (which ever major brand was on sale) up to 47,000 miles. I generally change oil qt 3 months/3,000 miles. Less frequently if lots of highway miles, e.g. a 2,000 mile road trip involved. Never more than 5,000 miles/6 months.

At 47,000 miles I switched to WalMart SuperTech full synth 5-30. Toyota filter every other oil change. No leaks, no squeaks. Runs like a top.

I believe that the proposition, that synthetic oil causes leakage, is just plain old B.S.

 

mine had conventional until about 90K switched to full synthetic no leaks. The car has about 210K now.

 

Thanks for the feedbacks. Makes me feel more confident to switch to full synthetic this week. Already got the gallon of the good stuff.

 

Yeah my local wallymart (austin) has been really low on large jugs of motor oil, for months.

As others said, no problem switching over to full synth, pick your brand. I would recommend though, you look for a High Mileage type, those have more of the additives to help an engine's internal seals stay sealed and not leak.

I've used Mobil 1 and Castrol (both high mileage full synth). Mobil claims theirs will 'clean' out your engine's innards of carbon/oil deposits in one OCI while Castrol claims theirs has a phosphorus substitute that helps extend cat convertors lives. Don't know about all that yet I think even a Wally Full Synth High Mileage would be a great motor oil, its probably one of the above....

 

Switched my Camry over to high mileage synthetic at ofer 100k miles (it was also pretty old as well). My 07 corolla has had synthetic for a long time (maybe since new?) and has been fine.

if it starts leaking after you switch to synthetic, it was going to leak anyway. Fix it and enjoy the benefits of synthetic oil

 

if it starts leaking after you switch to synthetic, it was going to leak anyway. Fix it and enjoy the benefits of synthetic oil

What are the benefits, other than it being easier to find and buy?

 

I switched to synthetic in my 2005 4runner with 200,000 miles but I had to switch back to conventional the same day. I got leaks everywhere.

Once the conventional 0W 30 was back in the leaks slowed and eventually stopped completely (i.e., a drop now and then!).

If you change your oil every 5000 miles, Conventional is better IMO (especially in an older V6 Toyota 4runner). I get one drip a week in my 17-year-old 4runner - which starts and runs like a new truck.

My runner was built in Japan.

BTW. I never put any oil additives into my oil in the 17 years I've owned this 4runner.

 

Here’s my experience with synthetic oils.

I got my corolla xrs used with 68k. Immediately went to mobil1 synthetic oil. Around 120k, I noticed the oil pan weeping. This was right around 2018 and I noticed that the oil I was buying was mobil1 high mileage synthetic. Didn’t realize that it wasn’t the original mobil1 full synthetic. The weep became a leak. Had to reseal my oil pan. It wasn’t too bad of a job to do.

It all depends on the seals. Specifically you front and rear seals. Last thing anyone wants, is a blown oil seal.

 

Use synthetic without a worry. Just extend your drain intervals or else it's just more expensive.
I routinely switch from synthetic Mobil 1 to Pennzoil, which ever one is on sale at the time.

 

Right now I change my oil around every 3K miles. If I switched up to full synthetic, how longer can I go before an oil change?

 

Easily 5-6 thousand miles. I change my oil every 10-12,000 kms. Most people change their oil too early.

 

I did every 5k oci. Just keep an eye on your valve cover gasket and timing chain tensioner. Timing cover leaks too.

When I did my valve cover gasket, I used felpro blue gasket set. It was ok, but I had a blow out in about 20k. Use oem if you can get it still from a dealer.

 

Speaking motor oil for your Corolla...I stumbled across this a while back:

. I actually had no idea that routine 10,000 mile oil changes were becoming a fact. It's worth watching the whole thing, but basically the Lexus owner followed the factory minimum oil service requirements. No issues up to and beyond the warranty period, but by 180,000 miles the pistons and cylinders were junk. That's a Lexus, not a Kia mind you.

 

Thanks for the video. Good to know that 10K oil change is not a good idea. I think I'll stick close to 3K since it's an old 2005 car.

 

Change oil once a year with 0w-30 Mobil 1 synthetic (about 12,000 miles) Oil still clean & no burning or leaks @ 190,000 miles. Car runs great & still averaging over 41MPG. (41.4 over the last 4 years)

 

For those of you experiencing problem getting oil at Wally World, you can buy most motor oils from Home Depot. I use Castrol Synthetic and it is literally pennies more than WM. I order online, drive by and pick it up. PLUS, I don't have to go to Walmart. Win-Win

 

Shell Rotella T4 15w40 Diesel Engine Oil works really well for older cars, as it conditions the seals, rings, and gaskets. And it works well in motorcycles, as it's MA rated. Most "synthetic oil" isn't all that "synthetic". There is a whole website by a chemist that goes through all of it, with additive break downs and so forth. But in reality, "full synthetic" is better oil, and can work longer. But the sooner you change it, the longer your rings will last. Mobile 1 is the winner in most testing, but Walmart's and Costco's are up there and a lot cheaper. So then it becomes a balancing game of how often can I budget the oil change vs. how long I want the engine to go before a very expensive ring change? 3000 miles and/or 1 year is the old school timing, and it works to extend you rings for a very long time.

 

You are over thinking it. Just put the correct weight oil and amount and get on with life. If you to see a bickerfest about what brand or syn then you’ve started the right post.

 

Hoarding at its best now.

 

Noticed a shout out for Pennzoil rebate above. Got some Platinum full synth, very fast fulfillment on it. Mobil1 also currently has a hefty rebate: $10/jug (I think the Pennz was the same) on the full synth, on until 9/30. They have it every year. Note, Walmart is not listed as one of their retailers, but they have always honored it.

 

Hi everyone,

My 2005 Corolla has about 147K on it. I've been using the Mobil Super conventional 5w-30 for years but the other day, I checked Walmart and Advance Auto and they all seem to be out of this type, and only have the full synthetic oil from Mobil. It's 2022 now and I'm concerned that switching to full synthetic could cause leaks. I've had to replace the engine gasket and the intake manifold gasket before due to leaks but that was five years ago or so.

Has anyone switched up to full synthetic and did you have any leak afterward?

I also see Pennzoil has a great deal on full synthetic oil. Should I stay with Mobil or can I safely switch over to Pennzoil with this upcoming oil change?

I use Shell Rotella 15_40 and wix filters on my 94 . I have almost 404,000 miles now , i dont like synthetic oils much .

 

Oil can't cause an oil pan leak. Can't remember when Toy stopped using oil pan gaskets, but once sealed and cured, that sealer shouldn't allow a leak.

Any problems switching to synthetics are supposed to come from oil that wasn't changed often enough forming sludge that covers the seal.,when the seal goes bad, the sludge acts as a seal, and the synthetic cleans the sludge away, letting the seal leak. Maybe poor crankcase ventilation building up pressure? Loose fasteners?

 

Oil can't cause an oil pan leak. Can't remember when Toy stopped using oil pan gaskets, but once sealed and cured, that sealer shouldn't allow a leak.

Any problems switching to synthetics are supposed to come from oil that wasn't changed often enough forming sludge that covers the seal.,when the seal goes bad, the sludge acts as a seal, and the synthetic cleans the sludge away, letting the seal leak. Maybe poor crankcase ventilation building up pressure? Loose fasteners?

Blow out is possible. The seal doesn’t last forever. Mine looked to be factory and failed at 120-140k.

edit : pressure build up plus thin fipg or rtv can create a weak spot.

 

Like others here OP, my Corolla didn’t get synthetic until about 120k miles. It’s currently at 170k - I’ve switched multiple times between syn blend and full synthetic as well as between 5w20 and 5w30 - the car keeps running like a champ. I do my oil changes between 5k - 5.5k miles.

 

No

 

Hi everyone,

My 2005 Corolla has about 147K on it. I've been using the Mobil Super conventional 5w-30 for years but the other day, I checked Walmart and Advance Auto and they all seem to be out of this type, and only have the full synthetic oil from Mobil. It's 2022 now and I'm concerned that switching to full synthetic could cause leaks. I've had to replace the engine gasket and the intake manifold gasket before due to leaks but that was five years ago or so.

Has anyone switched up to full synthetic and did you have any leak afterward?

I also see Pennzoil has a great deal on full synthetic oil. Should I stay with Mobil or can I safely switch over to Pennzoil with this upcoming oil change?

The last time I read anything about this issue was some years ago, but I would think the info is still valid. When your motor has that many miles with dino oil, sludge builds up in the motor. This sludge helps to seal any cracks that develope in your seals, which is normal. If you start with full synthetic from the jump, when motor is new, or switch to full synth before ~75K miles you should be fine. However, with high miles on the motoer, switching to full synth can be counter productive because it will break down the sludge which is filling the cracks in your seals, thereby causing potential leaks. Using full synth from the start helps prevent seals from drying out in the first place. Almost all, if not all new Toyotas (and other brands) come with full synth from the factory and recommend it for all oil changes. Maybe there's some additive that you can use to help your seals, allowing you to switch, but I've never heard of any myself. Worth exploring, I guess. My '06 Corolla has had full synth since the first change. I bought it new. It still runs perfect and uses/burns no oil between changes...with over 370K miles on an untouched motor. Only routine plugs, oil/filter, O2 sensors, shocks, brakes, battery. Still original exhaust.

 

I do not know why synthetic oil would "cause" any leaks. This was I think a thing on much older vehicles back in the day with synthetic oil when it first came out. But now days seals and synthetic oils are compatable with eachother, should not Cause any leaks or issues at all.

If you have a more modern vehicle and starting synthetic oil and got a leak, it most likely was a bad seal to begine with.

Now what could cause a seal to leak would be for instance using a "high Mileage" oil in your car before it ever had any leaks or issues. High mileage oil has additives in it that cause the seals to swell. If you have a seeping seal somewhere, adding a high mileage oil will help that old seal to swell and pinch off the leak. If you then later switch to a non high mileage oil without the additives, the seal will eventually shrink back down and your leak will come back. OR..... a mistake some people make, they have seals that are fine and do not leak, but the car is older so they think high mileage oil (Conventional or synthetic) will be something good for their car, like old people vitamins for an old person. So they use the High mileage oil with the seal additives, the seals that do not leak now swell and deform a little, then one day the owner does an oil change with an oil that does not contain the additive and over time the seals shrink a bit and now you have a leak from a seal that was caused from a change in oil, once you go high mileage oil in your car, you kind of have to stick with it or you risk developing a leak from a seal/gasket.

 

I do not know why synthetic oil would "cause" any leaks. This was I think a thing on much older vehicles back in the day with synthetic oil when it first came out. But now days seals and synthetic oils are compatable with eachother, should not Cause any leaks or issues at all.

If you have a more modern vehicle and starting synthetic oil and got a leak, it most likely was a bad seal to begine with.

Now what could cause a seal to leak would be for instance using a "high Mileage" oil in your car before it ever had any leaks or issues. High mileage oil has additives in it that cause the seals to swell. If you have a seeping seal somewhere, adding a high mileage oil will help that old seal to swell and pinch off the leak. If you then later switch to a non high mileage oil without the additives, the seal will eventually shrink back down and your leak will come back. OR..... a mistake some people make, they have seals that are fine and do not leak, but the car is older so they think high mileage oil (Conventional or synthetic) will be something good for their car, like old people vitamins for an old person. So they use the High mileage oil with the seal additives, the seals that do not leak now swell and deform a little, then one day the owner does an oil change with an oil that does not contain the additive and over time the seals shrink a bit and now you have a leak from a seal that was caused from a change in oil, once you go high mileage oil in your car, you kind of have to stick with it or you risk developing a leak from a seal/gasket.

Good point. I would have stayed with the conventional oil I used from Mobil 1 but couldn't find them at Walmart or elsewhere. Only place I found it was in another state's local chain store. My Walmart now only has full synthetic.

 

Scotty Kilmer's synthetic vs regular oil
Synthetic Oil vs Conventional Oil - Which Type For Your Car Engine
Synthetic Oil vs Conventional Oil - Which Type For Your Car Engine - YouTube