Benefits from Synthetic Oil

[snigma]

I have a 97 Prizm 4A-FE, with 125k miles on it, no problems but the engine seems sluggish and rough.

Now, what benefits can I expect from Synthetic Oil after a good flush? Any kind of mileage improvements? I'm getting 27MPG City right now, pretty bad for a 1.5L engine

[Bitter]

4afe is 1.6L
correct tire pressure will do more than switcing to synthetic oil will.

[3S-GTE pRIZM]

well even if it didnt do anything for your motor it would help the economy...YAY ECONOMY

[Bitter]

lol, i run synthetic blend mobil1 since its a little cheaper. the 7500 mile oil lasts me about 6 months between changes, or i do one if i hit about 4000 miles.

get a new cap, new rotor, plugs, wires, topend cleaner treatment, run a cleaner through the oil, and check your compression.

[snigma]

Yeah, the tire pressures were low (around 22-25), so I upped them all to around 32-35 (a range, because I had already driven a bit to the pump, and i'm sure the guage is not entirely accurate, and might as well, 2-5psi over shouldnt hurt. I'll also watch the economy as it gets closer to 30 to see if it helps any).

The tire pressure increase helped 1.6MPG over the course of a tank of gas. But this time, I also drove the car more normally instead of more economically. Decent starts instead of crawling starts, 99% AC usage instead of leaving window open.

Will Synthetic make the engine run smoother? I think it would just be an expensive thing that won't do much except for the placebo factor maybe?

Also, Bitter, reading your post. Haha, excellent suggestion. Only thing: I'm looking to just get a really really cheap enhancement out of this car. Maybe I should change the AIR filter, something about the car just seems anemic. The 1996 Corolla with 1.8 7A-FE (although, that only has 55k miles on it) seems a lot more peppy and really smooth compared to the Prizm. Think its cuz of mileage difference?

[Bitter]

could be the mileage, ya i did forget to mention air filter. a compression test will give an indication of how worn the engine is, post up what your numbers are for each cylinder and i can advise from there on.

[snigma]

How much are compression tests?

[AVANT]

Don't worry about diagnosing cylinder compression when it's running fine. Run a bottle of chevron techron concentrate (it's a lot more than the techron amount you get from the gas station) in your gas tank the next time you do your oil change and call it a day. When your gas is techron treated, drive it normal if not a little harder.

Changing to synthetic is not necessary, and on tired motors, it can be a bad thing because it can clean possible seals caused by your conventional oil which leads to leaks. Keeping up with your oil change and stick with conventional oil would be my recommendation to you.

[Flashmn]

Additives dont do shit. Nowadays it doesnt really matter if you have synthetic or mineral, they'd still fill the norms. Some speciality VW, Audi, Mercedes, etc might require some special formula, but for your corolla you can basically use anything.

I'd change the fuel filter, maybe get the injectors cleaned (if the filter hasnt been changed in a long time). Also check the plugs, rotor and cap.

[Bitter]

the tester is about $30 and you can do it yourself very easily. no harder than changing sparkplugs infact!

[fistofmeat]

Originally Posted by Bitter

4afe is 1.6L
correct tire pressure will do more than switcing to synthetic oil will.

not true, when i replaced my oil pan and gasket on my ae92 4afe, i used (recommended by a friend) royal purple 10w30 full synthetic. paid an arm and a leg for it, but before the the oil change, i had a leaky head bolt (oil leaked from the seal around it, slowly, but it was leaking never the less). after the synthetic oil change, head bolt seal stopped leaking. sounds and feels less old now too...

[toyota_b]

From what i read on all of the posts a good tune up would be your best bet... cheap or not you probably need it.

[w203]

Originally Posted by fistofmeat

not true, when i replaced my oil pan and gasket on my ae92 4afe, i used (recommended by a friend) royal purple 10w30 full synthetic. paid an arm and a leg for it, but before the the oil change, i had a leaky head bolt (oil leaked from the seal around it, slowly, but it was leaking never the less). after the synthetic oil change, head bolt seal stopped leaking. sounds and feels less old now too...

It should be the other way around. Synthetic is thinner and would seep through any leaks/holes while conventional oil is thicker. But you did change the oil pan and gasket so that should have fixed the leak.

I too use Royal Purple, switched from lesser known synthetic and experience no difference. And this was on a high performance car/engine. With a Corolla I highly doubt there will be a difference felt. Your only paying for the name RP.

[Bitter]

Originally Posted by fistofmeat

not true, when i replaced my oil pan and gasket on my ae92 4afe, i used (recommended by a friend) royal purple 10w30 full synthetic. paid an arm and a leg for it, but before the the oil change, i had a leaky head bolt (oil leaked from the seal around it, slowly, but it was leaking never the less). after the synthetic oil change, head bolt seal stopped leaking. sounds and feels less old now too...

he was asking if syn would give him better fuel mileage, which it wont.

[fistofmeat]

i don't get how an oil pan and gasket can fix a leak oin the head... and to bitter, he asked for benifits, so i gave my experience which expressed the benifit that it may improve the health of the engine, and from my experience, it did, unless it is possible for a head bolt to stop leaking from repairs i did on the bottom of my engine... the engine was replaced and has about 15k on it, head bolt leaked for about the last 2 yrs or so, then i was doing stupid stuff, which resulted in the oil pan getting crushed a couple of months ago, so i replaced it, used better oil, and had good results.