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The things I think about.

So both my cars that use Royal Purple 5/30 engine oil do not exhibit oil consumption or HG leaks. The one is the VDC and HG leakage is a non sequitur , the other is an EJ253 in an Impreza. The "test" vehicle.

The Impreza is the curious one because when I picked it up the HGs were showing signs of an oil leak with wet oil buildup and I had decided to pull the engine and swap in MLS gaskets for correction and long life without worrying about it after I got the VDC back up. But, I did the catch up maintenance on it - timing components, plugs, cleaned the PCV - I changed the oil with Royal Purple 5/30 and used a "Full" oil filter. I run 93 octane gasoline in it for reasons plenty of members know about - it's better for it - and it's getting 24 mpg.

Given that the VDC doesn't use oil and now the Impreza after 1600 since I put in the Royal Purple is still on the full dot, I am starting to wonder whether it's the oil or not. The HGs and bottom of the Impreza engine is "dry" with only dirt build up where the wet oil was. I've not cleaned the bottom of the engine.

Now I drive my cars. The Impreza sees good highway speeds in the morning and can't get past 2nd gear in the evening (thank you bonehead drivers) during most of a 21 mile drive that takes up to 1.5 hours. So it gets a variety of driving styles. The AC is on all the time. Oh, and it's an automatic.

What I am going to do is at the next oil change I am going to put in a different oil and monitor the "leak" and consumption over a 3k miles interval. I'll use a synthetic blend Castrol 5/30 High Mileage. Depending on the results, I'll either go back to RP or use a different oil to continue the experiment.

I would like to have volunteers who own cars with the EJ 251, 2, or 3 that have HG leaks to switch their oil type to Royal Purple and see if a change in the usage/leaks transpires. I wouldn't want anyone to clean or change their PCV valve yet, just the oil brand and maybe viscosity the first go.

If you do your own oil changes, Wal Mart has 5 qt Royal Purple at a reasonable rate for online ordering. Other suppliers have good pricing also. Use your same filter brand you have used in the past. This is to see if the Royal Purple is the catalyst for slowing/stopping oil consumption and leaks.

After the first 3-5k miles with RP oil, then I'd want the PCV cleaned or replaced to further determine the loss factor.

Anyone willing, post up. There's only a few dollars more cost in the oil, but if the leak stops that means the HG repair will be offset.

If anyone has seen this type of change in their engine oil use or loss with another oil, let us know.
 

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My EJ253 has had the HG repairs done, and although at 137k miles it's consuming a little bit of oil, it's not the HGs (1 qt between changes; doesn't really start dropping until 2k miles after the change). I simply monitor it and add as needed.

But your experience with RP suggests it might be a worthy test to perform even with sound HGs. I'll consider it next oil change, given the reasonable cost at Walmart (and I see my local store has it in stock on the shelf!).
 

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My EJ253 has had the HG repairs done, and although at 137k miles it's consuming a little bit of oil, it's not the HGs (1 qt between changes; doesn't really start dropping until 2k miles after the change). I simply monitor it and add as needed.

But your experience with RP suggests it might be a worthy test to perform even with sound HGs. I'll consider it next oil change, given the reasonable cost at Walmart (and I see my local store has it in stock on the shelf!).
Are you running synthetic?
 

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Are you running synthetic?
No - dino. Chevron 5W-20, only because it's low cost and easily available at Costco.

Theory is that at this rate of consumption, and my relatively short change interval (4000 - 4500 miles), it doesn't matter much what I put in. @cardoc's experiment with RP might change that; we'll see.
 

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I've got a 2009 legacy I can probably test for you. I still need to clean it up and confirm but I think it's still leaking oil from the head after i replaced the oil puking pressure switch.

it's not the HGs
it seems that's exactly what the purpose of this test is intended to isolate.
 

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it's not the HGs
it seems that's exactly what the purpose of this test is intended to isolate.
OK, fair comment. What I should have said was "This time I don't see any sign of HG external oil weeping or leaks, which was the symptom shown with the original HGs around 101k miles, prior to replacing with multi-layer HGs - and a quart of consumption would easily be seen if it were a leak".

Note also that I replaced mine fairly early after discovering the HG weepage, simply because it was almost due anyway for timing belt replacement, and it made sense to combine the labor for that work into the HG replacement (which my indie mechanic had offered to do). The amount of oil weeping at that time would probably not have been enough to register on the dipstick, and I would thus caution anyone participating in this test that they should follow your procedure - clean up the bottom end, then periodically inspect underneath for evidence of weepage or leaks, rather than depend on the dipstick.
 

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This piqued my interest because I have an '09 Impreza EJ253 2.5 NA and it's leaking oil at the heads. How's the bottom of your engine under the heads at 2300 miles?
 

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Discussion Starter #10
This piqued my interest because I have an '09 Impreza EJ253 2.5 NA and it's leaking oil at the heads. How's the bottom of your engine under the heads at 2300 miles?
Dirty. Just dirt that has gathered around what was once wet. It's all dry.

I haven't washed the engine bay at all, nor the undercarriage. I just eyeball it every once in a while.

I will note that I check the oil level every morning before the first start up, so it's not after it's been run, only after it's sitting. This gives a more accurate measure of use. Or in this case, non-use.
 

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I may try the RP at the Impreza's next oil change (another 1500 miles, I go 5000). Kind of expensive but if it saves a head gasket job it'll be worth it. I know what you're saying about replacing the PCV valve and oil brand at the same time, but I probably should look at the PCV, the car has about 83k on the clock, 10 years old, and as far as I can tell it's never been changed. Just got it last fall.
 

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Discussion Starter #12
Something that came up in a text with another member is the cost of the Royal Purple.

If the oil is in fact the reason the car stopped using and leaking oil, then the cost is offset by not having to replace the lost/used oil.

So here's the math.

5 quarts of RP 5W30 is about $35 from Wal Mart online. Another quart for a 6 quart oil change in an H6 would be an additional $9-10. So we'll go with $10. That's $45 for oil at the time of the change.

5 quarts of Pennzoil 5W30 is about $20 plus an additional $5 for the 6th quart. That's $25 at the change.

If the car uses a quart between oil changes, interval of about 3k miles, then you have to buy a 7th quart at $5 for Pennzoil, which puts your oil change cost at $30.

If the Royal Purple is the catalyst for stopping a HG leak, then that HG repair at $2000 average is offset even more.

The Royal Purple lets me go 10k miles on the VDC H6, and I don't have any loss except from the oil filter change at 5k miles which means I have to buy another quart. That puts my oil cost at $55 over 10k miles which when you cut it in half would be $27.50 plus the oil filters for 5k miles interval. I get Full oil filters for less than $2 each. And actually, I only use about 1/2 quart with the filter change and the other 1/2 goes on the shelf for the next 5k mile filter change, so it's less than $27.50.

If I was to use another oil in the VDC, I would have to change it every 3k miles, probably have to have the extra quart between and that would put my cost over $105 for 3 oil changes, plus the filters, and it's still 1k miles shy of the 10k mile RP use. Which would actually come out to more than $110 over 10k miles.

So just having the benefit of a 10k mile oil change is saving oil cost. Not to mention the no loss/no use factor in the VDC.

The Royal Purple is cheaper to use and more beneficial. At least in my VDC. We'll find out about the Impreza in the next 7-10k miles.
 

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The more the merrier. I have decided to run the Royal Purple to 5k miles and since Castrol GTX is a popular oil, I'll put that in and we'll see what happens.

Since I don't drive a great distance any longer, this car about 50-70 miles a week, it may take a while to get the 5k mark.
 

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Welp, did the oil change today, RP, cleaned the head gasket areas under each side. No other parts. Honestly I’m skeptical this will solve the minor oil leak at the heads but we’ll see.
 

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I started driving the one with an oil leak. Fixed a typical leaky valve switch/sensor and need to clean it up first to verify HG. After that I’ll do this. Thanks for the RP sources, I thought I had to find a small local dealer.

Im sure you’ve thought this through and have rolled eyes at anecdotal local HG explanations and commentary. In general it is a stretch to assume universal principles from one example. What’s the difference here?

What’s the history, have the HG ever been replaced, and could it have been PCV valve related?
 

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Discussion Starter #20
I run RP in my VDC and it doesn't use any oil. I thought it was because I keep everything proper on the car and it breaths great.

The Impreza had 114...k miles on it when I got it. I'm the second owner. It's out of NY. The maintenance record does not indicate HG repairs. The typical oil residue is on the bottom of each head seam and running to the back of the engine and front of the front diff indicates a HG leak. No oil cooler on this one. Nothing leaking from above the oil pan line and the oil pan is definitely not leaking. Original Fuji Bond is on it. There is no indication that the rear seals are issues either.

I've cleaned PCV valves on a lot of EJs and not had this result. As I stated above, it is odd that the EZ30 is not using oil at all and now the EJ25 has stopped leaking.

Royal Purple sticks to everything and doesn't clean off easily. I had a PCV valve jam closed on the EZ30 at the dragstrip one night and the dipstick popped out from crankcase pressure and sprayed the front of the engine with RP. I cleaned it as much as I could with brake cleaner from another crew at the strip, but the belt slipped on the pulleys all the way back to Austin from Little River Dragway. I had to change the belt and scrub the pulleys with a stringent degreaser and a brush to get the RP off.

I'm not saying with certainty that the RP is key in stopping the HG leak. Time will tell. But how many owners do not go through ANY measurable oil in 2800 miles.
 
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