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**kjchernov** · 03-26-2011, 11:12 PM

Well, there are no need to change oil viscosity when your engine is going to high-mileage stage. Engines are designed to run on a certain motor oil. As far as I know, Festiva's engines are designed to run on 5W-30 motor oil.

A fairy tale about "increasing viscosity of motor oil with increasing your car's mileage" is just a PR action. You should use the same motor oil which was in your engine from beginning.

I'm using "Mazda Golden SM 5w30" oil, and can say that it costs its price.

**Team Lightning** · 03-26-2011, 11:23 PM

I've run 10w-30 in mine for 20 years. Still going strong.

**Zanzer** · 03-27-2011, 03:16 AM

Most new cars are spec'd to run 5W oils because many newer cars have much tighter oil tolerances than they did 15+ years ago. They did this to insure that, with the tighter tolerances, oil gets to the places it needs to be faster. This is especially true in OHC engines where the cams are in the highest part of the motor and typically don't have cam bearing inserts like older motors. They want to make sure these parts get oil as soon as possible. Another reason is that most 5W oils have a synthetic component (plus being thinner) help give slightly better CAFE numbers. If I recall correctly there was a Ford bulletin floating around that suggested switching to 5W oils even in older model vehicles. Partially due to aid in startup lubrication and partially due to slightly better fuel efficiency (tenths of a mile per gallon). The bulletin is probably why it's showing up in his computer different that the original owners manual.

I own quite a few vehicles who's models cover at least 3 decades and I switched everything (including the Festy) over to 5W-20 in the winter and 5W-30 for summer a few years ago without any issues. One reason was so I didn't have to keep 5 different viscosities of oil "in stock". The only exception is my F-450 7.3 diesel that still gets Rotella 15W-40. I've always ran 5W oil in my 98 Mustang GT in the 11 years that I've owned it and I've had 4 sets of cams in the car over the years; NPI's, PI's, SHM's, and the Comps that are in it now. Every time I've went in to swap cams the engine is pristine inside and the cam journals look like new.

**Zanzer** · 03-27-2011, 04:24 AM

EDIT: The "thinner" comment was in reference to 5W-20 vs. 5W-30, 10W-30, and 10W-40

**rmp2711** · 03-27-2011, 07:07 AM

Back in the 90's my Mom's 76 Nova (250ci. straight 6) started smoking and had a blow-by problem. Took it to a shop to have a rebuilt motor installed. The shop owner said the only oil he would use,and recommend to his customers is Castrol GTX. So I have been using 5W 30 in my Festiva ever since. I have almost 300,000 miles on my car and its the only oil I use.

**Twistiva** · 03-27-2011, 07:14 AM

Originally posted by kjchernov View Post

Well, there are no need to change oil viscosity when your engine is going to high-mileage stage.

kjchernov -

I think you misunderstood my post. I'm not saying that Jiffy Lube's database recommends 5W-30 because my Festy is a high mileage car. I'm saying they recommend 5W-30 because they claim it's a better viscosity for Festys. The 'why' is what I don't know. Again, he said most new cars run on 5W-30 oil nowadays. He showed me I could get 10-30W 'high mileage' oil, which is what I did. The issue of viscosity and specialized high mileage oil are 2 different questions. If I don't hear any overwhelming arguments against 5W-30 I guess I'll be switching to that next time.

**Twistiva** · 03-27-2011, 07:18 AM

Originally posted by Zanzer View Post

Most new cars are spec'd to run 5W oils because many newer cars have much tighter oil tolerances than they did 15+ years ago. They did this to insure that, with the tighter tolerances, oil gets to the places it needs to be faster. This is especially true in OHC engines where the cams are in the highest part of the motor and typically don't have cam bearing inserts like older motors. They want to make sure these parts get oil as soon as possible. Another reason is that most 5W oils have a synthetic component (plus being thinner) help give slightly better CAFE numbers. ......

Zanzer -

Thx for the detailed post. Makes sense to me. I welcome inputs from anyone else on here.

**kjchernov** · 03-27-2011, 07:48 AM

Originally posted by Twistiva View Post

The issue of viscosity and specialized high mileage oil are 2 different questions. If I don't hear any overwhelming arguments against 5W-30 I guess I'll be switching to that next time.

No, I havent misunderstood your post. I'm only saying, that 'high mileage oil' is just a PR action, and nothing more.

You will get no arguments against 5w30, because it's a vicosities your engine was designed to run on. It is a viscosity your engine needs. Nothing else will fit. (ofc, your motor will run even on 15w60, but it's not optimal for it). If you want, you can play with first number (5w30, 10w30, 0w30) depending on your temperature (in winter, when the temperature were -38C outside, I used 0w30, because otherwise my engine wont start), but not with second one, because it's a viscosity which oil will have on a hot engine, and by changing it you will cause your engine to warm up, then calm down again, again and again.

The main feature in motor oil is a viscosity. All other things like cleaning abilities etc. are 10th factor.

P.S.> I dont know about USA, but here, in Russia, we avoiding using of Castrol, Shell and Mobil oils, because they can cause damage to your engine. Hope, that situation with them in your country are much better.

**FordFestiva** · 03-27-2011, 07:56 AM

I use 5W30 in summer and 5W20 in the COLD winter. The thinner oil enables for quick lubrication throughout the engine.

**Zanzer** · 03-27-2011, 10:42 AM

Twistiva - Glad I could be of some assistance

There is TONS of debate on the net about oil viscosities and what is best. I did a lot of reading and research before making the switch. It's been a few years now and so far I've had zero issues...and I drive most of my vehicles pretty hard at times.

kjchernov - It's interesting that you have trouble out of Castrol, Shell, and Mobile oils in your country. I run Castrol in my Harley Davidsons and in my Suzuki Katana because it doesn't foam at high RPM's like some other oils and I've had great luck with it in cars. I've always used Shell Rotella in my diesels and I know a few people who run it in their flat tappet motors due to it being one of the few oils that still has some ZDDP in it. As for Mobile, I know a few guys that would walk before putting anything else than Mobil 1 in their engines LOL :mrgreen:

I wonder if they use different formulations or something in your country? Personally, I think the dubious oils here are Quaker State and Pennzoil..although I'm sure (as with any other product) you'll find those that swear by it and wouldn't use anything else.

**kjchernov** · 03-27-2011, 10:48 AM

Well, there is an easy explanation. In Russia many things are poor. Here, all that people do is earning as much money as they can by doing nothing. We can't find REAL Castrol/Mobil/etc. here, because they are always tampered by someone else.

I just dont know about such things in USA, so I decided just to warn you. Sorry, if I did something wrong.

**Zanzer** · 03-27-2011, 11:02 AM

Oh no, you're totally fine! Sorry if I sounded accusatory or anything, I was just curious if it had something to do with formulation or just the quality as you stated. And what you say makes perfect sense. We're lucky here because when we go get something off the shelf we can be pretty sure what we're getting is the real deal straight from the manufacturer. In many ways it's made us complacent because we can grab just about anything sitting on the shelf and have a high level of confidence that it is what it is.

**kjchernov** · 03-27-2011, 11:08 AM

Originally posted by Zanzer View Post

Oh no, you're totally fine! Sorry if I sounded accusatory or anything, I was just curious if it had something to do with formulation or just the quality as you stated.

Thanks

I'm rarely talking with foreigners, so I can sometimes be not very polite, because I'm not sure what is considering as polite and what is not.

**Twistiva** · 03-27-2011, 11:09 AM

Again, I welcome even more comments on viscosity. Based on Zanzer's posts, I'll probably use 5W-30 in something other than Penzoil. Maybe Valvoline?

However, anyone care to address my question about using oil specially formulated for 'high mileage' vehicles?

We've heard from at least one member that it's just PR bunk. He may be right. As I said, until yesterday I didn't even know there was such a thing.

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