truth or dare, synthetic blend or not in a ea81

[bheinen74]

1. will running synthetic blend in a ea81 have any bad side effects, ie leaks.

 

2. is this synthetic blend (castrol) really oil or man made- i think it could just be highly refined.

 

3. will this make my engine last longer

 

4. will i get better gas mileage

 

5. 5w-30 too light weight, i have been using regular gtx castrol 10w-30 but might switch for this winter

 

expecting answers from a few mods....and anyone else.

 

I searched but nobody said its okay on ea81 era.

Edited October 17, 2010 by bheinen74
b for n

[ettev]

Just my opinion:

 

1. I've been told by some pretty good wrenches that unless you're rebuilding the engine with all new gaskets stay with the oil you've been running. So, unless you're rebuilding your EA81 stay with the dino oil or run the risk of leaks out of gasketed joints.

2. It's a Group III oil, which I believe is considered natural oil. If I'm not mistaken there was a lot of flack about the name "Syntec" in that it was misleading in making people think it was pure synthetic.

3. So they claim. But so will dino oil if it's changed regularly.

4. Not sure.....never use it. But all the articles I've read claim synthetic yields slightly better mileage.

5. Oh boy, here comes a flame war. I like heavier oil weights especially on higher mileage cars. One of my good mechanic friends tells me I'm nuts and that anything over 10W30 is too heavy for anything regardless of mileage. I run 10W40 or 20W50 in my EA81's with no ill effects.

 

1. will running synthetic blend in a ea81 have any bad side effects, ie leaks.

 

2. is this synthetic blend (castrol) really oil or man made- i think it could just be highly refined.

 

3. will this make my engine last longer

 

4. will i get better gas mileage

 

5. 5w-30 too light weight, i have been using regular gtx castrol 10w-30 but might switch for this winter

 

expecting answers from a few mods....and anyone else.

 

I searched but nobody said its okay on ea81 era.

[GeneralDisorder]

Sythetic is amazing stuff - but it's sole benefit IMO is that it simply lasts a lot longer. Easily twice as long as typical non-synthetic oil. It resists heat much longer before breakdown. Unfortunately there's no way to tell when it's got to be changed without oil analysis so for the typical car on the road it's not worth the price when you are just going to go with X number of miles for a change interval anyway.

 

It could expose gasket leaks but on the EA81 that mean valve covers and oil pan - which are not a huge deal to replace anyway and if they are indeed old and subject to leaking they probably should be done regardless of the type of oil you run. Either way those three gaskets are not a concern IMO as two of them take 10 minutes to change and the other about 30 minutes.

 

Run 10w30 - that's the only thing you should be using. Having tore down many EA81's and other Subaru engines I can tell you that the clearances in the engine don't change to any appreciable degree - I've pulled apart engines with over 200k to find the bearings and crank still well within spec. The argument that "heavier oil will fill in enlarged bearing clearances" is simply not born out in the data I've collected - I would submit that anything (clearance wise) large enough to need a heavier oil is way too far gone to get any benefit from it and is sure to blow up shortly regardless of what you put in it. Oil that is too thick will cause accelrated start-up wear mostly. It won't do much when the engine is up to temp. Heavier oils in the SAE rating are mostly for things like Diesels where the bearing pressure's are much higher. The insanely thick oil will not hurt an EA81 when at operating temp - but that thick sludge will cause serious engine wear when cold.

 

It's also best to avoid oils that have a very low "w" rating in comparison to their SAE rating. This indicates a higher level of viscocity modifier - which is basically little plastic cork-screws that uncurl as they heat up. It means less oil in your oil. So unless it gets down to zero degree's where you live (in which case you should have a block heater ) then you should run 10w. IMO just about everyone should be running 10w and if it's cold where you live then get a block heater - they are a whopping $35 from the dealer.

 

GD

Edited October 17, 2010 by GeneralDisorder

[mcbrat]

I've run it in mine without any issues...

 

I've run 5w-30 in the winter sometimes, but not always...

[NV Zeno]

Here's my 2 bucks...

 

I've got 333,000 miles on my EA81. Oilpan gasket changed once, valve cover gaskets maybe twice. Heads and intake have never been removed. Sure, there were/are some small leaks, nothing major. Runs perfectly.

 

I've run 10w30 and 10w40 it's whole life, just about every brand. I make sure the level is up, and change the oil and filter every 4000~5000 miles. I live at 6000 feet, and it gets to around zero overnight for a few weeks a year in winter..no trouble at all.

 

I think GD covered it: just make sure the oil is changed regularly and topped when necessary, good to go.

 

Just my 2 bucks

[spazomatic]

flat tappets=conventional

rollers=synthetic

[NoahDL88]

Seriously, if it works for NV Zeno, it works, he's got a stack of license tabs on his plates about half an inch thick.

 

 

 

You could always start with a semi-synthetic blend, but conventional wisdom is that synthetic is more likely to leak out of older seals. (this info seems to be somewhat dated though, as syn oils have improved dramatically over the last 10 years)

 

Try Bob the oil guy, his site seems to have some good info.

[4drbrat]

My understanding is that putting synthetic in a high mile rig, like any subaru, has a potential of causing leaks and lowering compression. The theory is that gunky buildup that the rig has been running with inside the engine is cleaned out by the detergents in the synthetic oil. Since there are years of buildup all running through that engine at once, it can cause damage.

I have run synthetic in my POS subie without any problems so far, but I also rebuilt the heads right before that, so that previous post might be on to something, too.