Just put AMSOIL 5W30 in my 1998 Subaru Forester.

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The Forester was my fathers car and he put 116,000 miles on the car over the years. He decided to get a new car so I took the Forester off his hands. Besides some hickups in the transmission and normal old age the car is running well. The only bad thing is that it is only gettign about 21 MPG and I can't figure out why.... COuld be a transmission issue but I don't know (Part is due to driving at 70-80MPH but the other part I can't figure out)

He got the oil changed every 3-4K miles and alwyas got it done at a local shop so they probably used a cheap regular type of oil.

I decided to try goign to synthetic to protect the engine better and see if I coulf get some better milage by doign a engine flush. I purchased the engine flush fluid from AMSOIL and used it and then put AMSOIL synthetic 5W30 in the car with an EA AMSOIL filter.

Any comments/suggestion/ideas about this switch? How long do you guys think I can go with this oil and filter before changing it?
 
I guess that depends on which Amsoil 5W30 you got. I would also suggest you look at the Amsoil ATF fluid.
 
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I guess that depends on which Amsoil 5W30 you got. I would also suggest you look at the Amsoil ATF fluid.




I got the 100% Synthetic 5W-30 Motor Oil (ASL) from AMSOIL.

As for the ATF I am goign to avoid synthetic because I have heard it is bad to put a synthetic into a transmission that has run regular oil for so long and one that is having some minor issues already.
 
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I guess that depends on which Amsoil 5W30 you got. I would also suggest you look at the Amsoil ATF fluid.




I got the 100% Synthetic 5W-30 Motor Oil (ASL) from AMSOIL.

As for the ATF I am goign to avoid synthetic because I have heard it is bad to put a synthetic into a transmission that has run regular oil for so long and one that is having some minor issues already.




I'm not sure where you heard that because it wrong. On my truck, it has shifting issues at 105k when I changed it for Amsoil ATF. Now it doesn't have any problems shifting. I did have the whole transmission flushed and replaced which in my case was 16qts.

The ASL is a great oil, you'll be happy with it.
 
It has a studder between 1 and 2 gear and 2 and 3. IT does not catch and then jerks you a but. IT is just not smooth. IT is actually bettr if you get on it and drive fast thru the gears. SLower and it is worse.
 
[COuld be a transmission issue but I don't know (Part is due to driving at 70-80MPH but the other part I can't figure out)]

If the transmission is not working properly you may need a rebuild so I wouldn't worry about the ATF. If it was me I would try the ATF Amsoil because what you've heard I haven't seen proof. Amsoil is good ATF.

[Any comments/suggestion/ideas about this switch? How long do you guys think I can go with this oil and filter before changing it? ]

ASL is a very good oil you're using. If you have an old manual go by the manufacturer's OCI's. Me? anywhere from 5-7K miles before you change oil and filter. Get a UOA at 5K miles maybe you can save money leaving the oil in longer.
 
Heck on this car I am goign to leave it in there for at least 8K if not 10K miles.
 
If the transmission has never been changed, change it using non-synthetic. If that helps, drive it a thousand miles or so the make sure it is sound.
Then change it again, using the AMSOIL ATF.

You should be able to run at least 15,000 miles or a year on the engine oil.
 
My car was run on conventional dealership oil for the first 13 years of its life (130k miles) and I ran one Auto-RX phase, then I switched to Amsoil 5W30. No leaks before, no leaks after. I personally think that if the engine's relatively clean (take a look under the filler cap if applicable) and it has no leaks right now, it's not gonna leak on synthetic.
 
Thanks guys. I am probably goign to try to go to around 10K miles usign the oil and then do another change using AMSOIL again. Depending on the time of year I may go a little higher or lower with the oil weight....
 
Heck on this car I am goign to leave it in there for at least 8K if not 10K miles.

Sounds good the oil certainly won't be a problem.
 
Word of warning, but nothing major:

You may notice a little oil consumption with the first use of Amsoil synthetics. Don't be alarmed, it is common for higher than normal oil consumption to happen on the first use of synthetics due to cleaning of internal passageways.

I had this happen within 2,000 miles, but after changing the filter and topping off, I never had it consume oil after that.
 
A Forester is not the gas mileage champ. It's boxy and a little on the heavy side with somewhat low gearing. Plus it's AWD. Driving 10mph over the speed limit, 21 mpg is probably pretty good.
 
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A Forester is not the gas mileage champ. It's boxy and a little on the heavy side with somewhat low gearing. Plus it's AWD. Driving 10mph over the speed limit, 21 mpg is probably pretty good.




I agree with what you are saying but 20-21 MPG is still ----. Even when I try to use cruise control and maintain the RPMs under the 3K range I might only get 21.5-22 MPG. It is consistently low and I remember this car gettign 24-26MPG earlier in its life....

Has a new air filter and regular maintenance. I am not 100% sure when the spark plugs were last changed so that coudl be an item of concearn but I think they were changed not long ago.. Most I can do is just use good quality oil and keep up with mainteenance....

I had the ATF replaced by the dealer- regular fluid used.. Did not change anyhting.....
 
I would change the ATF and diff fluids to Amsoil as well.
There's actually a gas mileage forum over at subaruforester.org.

-Dennis
 
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I've heard of Amsoil ATF "fixing" shifting problems. But of course if it's too far gone nothing will help. It sure made my trans shift a lot better. But the trans only had 15k on it when I switched.

I guess one way to think about it is this; A full fluid change with Amsoil ATF will be around $150.00 if you have it done professionally. It might work, might not.

But a rebuild, oh I don't know, $1500.00 - $2000.00.

The Amsoil might be worth taking a shot.
 
My 2000 Forester 124,000 miles yields 27-28 mpg @ 72 mph on cruise and ~ 22mpg local with air on. As a side note the timing belt is due to be changed at 105,000 miles and this is an interference engine so don't skip changing it.
 
Interesting- Timing belt has been replaced 2 times. The 98 required it at 60K and I think 110K

GOign to leave the transmission as is for now...


My gas milage should be better I will look at subaruforester.org for more info
 
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