25000 miles on same oil - what viscoity?

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I have Amsoil Signature 5W-20 sitting in my e-cart, but should I go to a thicker 5W-30? What is likely to happen after such a long interval? The oil gets thinner over time (or thicker)?

2003 Civic Hybrid 1.3 liter
 
I personally would use 5w30 but the 5w20 should also work if you check its level and do a UOA.
 
Oil viscosity will end up going down initially before rising again late in the OCI. Think of a NIKE swoosh in reverse. The degree of the viscosity drop and subsequent rise is highly dependent on the oil, engine, and operating environment so getting a good prediction can be tough.
 
If you have leaky fuel injectors, then you would get fuel dilution, and viscosity goes down.
Fuel dilution and reduction of viscosity from excessive blowby can also occur from worn rings.
You have an older car, so I'd go with 5w30 there just in case.

If you don't get fuel dilution, then gradual oxidation increases viscosity over time.

Its usually "safe" for bearing/wear for an increase in viscosity, but a decrease in viscosity can be bad enough to cause more wear, maybe even a spun bearing (guessing when HTHS
I'd recommend putting in a seal conditioner on an old car going 25k between oil changes. Put it in halfway thru your long interval when the original oil's seal conditioner chemicals might be broken down. http://www.stp.com/products/oil-additives/high-mileage-oil-treatment

Fram Ultra oil filter beats Amsoil Eao on 4548-12 tests.
 
IMAG2605.jpg

Yikes! Lots of random stuff for friends!

But seriously I would pass on the Amsoil if you really are just looking for 4 stroke PCMO.

Go with the M1 from walmart with rebate. Especially if you are planning on running typical OCI.

23,780 miles on Amsoil same engine
 
Originally Posted By: veryHeavy
I have Amsoil Signature 5W-20 sitting in my e-cart, but should I go to a thicker 5W-30? What is likely to happen after such a long interval? The oil gets thinner over time (or thicker)? 2003 Civic Hybrid 1.3 l


Curious.... have you ever done a UOA? I'd like to see the results.
 
Same engine.... good to see the oil held up in an 08 Civic hybrid. And it got thicker with time.
Quote:
If you don't get fuel dilution, then gradual oxidation increases viscosity over time.

There's the answer I was looking for. At 30,000 miles Blackstone said the car had no fuel dilution in the oil, and at 80,000 it's probably still good. It sounds like the 5W-20 will gradually move towards a thicker oil (due to oxidation).

Honda recommends 0W-20 but the 0W costs $2/gallon more than the 5W, so I chose the 5W. It's interesting how Amsoil SS changes the price based on the viscosity. Strangely 0W-40 is the cheapest of all, even with its wide Viscosity Index:

0W-40 $2035 (fifty-five gallon drum)
10W30 $2076
5W-30 $2076
0W-30 $2156
 
Originally Posted By: veryHeavy
It's interesting how Amsoil SS changes the price based on the viscosity. Strangely 0W-40 is the cheapest of all, even with its wide Viscosity Index:

0W-40 $2035 (fifty-five gallon drum)
10W30 $2076
5W-30 $2076
0W-30 $2156


I dont think amsoil prices based on viscosity per say

I think their prices were based on what it costs them to produce X product.
 
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This does not seem like a good idea. What is your driving conditions? If you do all highway miles, hundreds of miles a day, 60k a year, then 25k might work. Use a long life synthetic filter like Fram Ultra or WIX XP

Either way, please get a UOA for us at the end of the 25k OCI. Napa has the best price on it, $14, and it includes TBN. Ask for part #4077
 
I drive 110 miles round trip to work / day, 5 days a week.. usually end up with about 600 miles on the clock per week including trips to the store/lunch.. and there is no way I would ever run a 25k OCI, even using Mobil EP. 15k, MAYBE.. using a Fram Ultra.. but never 25k.

I don't care what AMSoil says, 25k is too long on any SN/SM oil.
 
Originally Posted By: SirTanon
.. and there is no way I would ever run a 25k OCI, even using Mobil EP. 15k, MAYBE.. using a Fram Ultra.. but never 25k. I don't care what AMSoil says, 25k is too long on any SN/SM oil.


That's a wonderful opinion, But I've seen vehicles go MUCH further than 25,000 miles on Mobil 1 - back in the 1990's.(SG-SH oil?)

There was no such thing as synthetic filters back then. Two vehicles I know of first hand ran over 50,000 with Mobil 1 and the engines seemed to be fine from a cursory examination.

I'm not saying it's a good idea for everyone, but there's probably enough science to suggest that it's possible without causing major problems.
 
Originally Posted By: SirTanon
I don't care what AMSoil says, 25k is too long on any SN/SM oil.

This guy did it. Do you see any flaws with his analysis which may have damaged the engine?
23,780 miles on Amsoil same engine

So anyway I picked-up a jug of Amsoil SS 5W-30 for $27 flat (plus tax). I figured that's as cheap as it will ever be, so I'm ready to do my 25000 mile run.
 
Originally Posted By: veryHeavy
I figured that's as cheap as it will ever be, so I'm ready to do my 25000 mile run.


How far are you into it?
 
Originally Posted By: Linctex
Originally Posted By: veryHeavy
I figured that's as cheap as it will ever be, so I'm ready to do my 25000 mile run.

How far are you into it?

You may be waiting a long time for that response since user veryHeavy was escorted off the premises. Unless of course a reincarnation answers you, which is quite possible.
 
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