How does a modern 5w30 compare to a 1990s 10w30

[TallPaul]

I find it hilarious that nobody ever suggests doing a leakdown test to determine if it is rings. Just FYI, dumping a teaspoon of oil down a cylinder and doing a compression test is a bs test. It will artifically inflate numbers on practically any engine regardless of health.

If you're eating a quart every 300 miles it's probably something in the valve train. Compression test coupled with a leakdown test should narrow it down and if it doesn't then it needs to come apart to determine why. This is assuming emissions stuff is good like PCV not plugged, etc.

And all appearances are that quart per 280 miles is mainly the one cylinder. If the valve train, why is only one plug fouling. The rest are fine.

Have not done a leakdown test but the car performs very well, so I think we are getting good power on that piston regardless of the consumption. Next time it is in a shop I will have them do the leakdown test. I put a new PCV filter in it some time ago. The old one was pretty plugged. But that did not help the oil consumption.

Really, with 150,000 miles, the car runs great (can chirp tires in second gear--Uniroyal Tiger Paw Touring), it is no longer smoking excessively and in fact is not even noticeable (maybe some should follow me to observe), I see no reason for any major surgery. This engine could go on for 10s of thousands of miles yet before we really need a rebuild.

 

[TallPaul]

A quart in less than 300 miles is severe consumption. No oil will fix that and suggestions of futzing with the winter rating is laughable. The only thing that might help is using a -50 grade, and at that level of consumption I would doubt it makes much difference.

That engine needs a rebuild.

Not 50 grade. I ran a 15w40 (franken oil mix of Valvoline MaxLife 10w30 with VR1 20w50) and the car smoked worse than ever. I think the thicker oil ended up having longer residence time in the combustion chamber and/or just being thicker made it produce more smoke. Also I get spec oil pressure with the Valvoline Restore and Protect 5w30 so a 40 weight would not necessary be the best move, though I never checked oil pressure with the 40 weight in it. .

 

[TallPaul]

A great candidate for Valvoline Restore and Protect and some Techron with 93 Costco gas!

We run regular I can't remember the octane here in Michigan, maybe 87 or 89, not sure, but what would a higher octane do for me? Isn't it mainly that the fuel companies put goodies like fuel system cleaners in the higher octane gas? If so, just an additive. We did put some Amsoil fuel treatment in and maybe I should do that every tank.

 

[TallPaul]

In that case is reasonable to try Berryman's B-12 piston soak before opening the engine.

I thought about the piston soak option but seems there is a possiblity of creating a nasty sludgy mess in there that could be counter productive at least initially but hopefully would blow out. Sometimes I think it is best to go gently with this, nothing drastic. She's runing great and that is what really counts for me. Adding oil gives me a chance to play with oil more anyway. And it is always fun to play with oil, right?

 

[4wd]

This is BITOG, bud. Valvoline Restore and Protect cured my baldness and fixed the pitting on my valve seats.

Colds, moles, and sore … never mind …

 

[maraakate]

I thought about the piston soak option but seems there is a possiblity of creating a nasty sludgy mess in there that could be counter productive at least initially but hopefully would blow out. Sometimes I think it is best to go gently with this, nothing drastic. She's runing great and that is what really counts for me. Adding oil gives me a chance to play with oil more anyway. And it is always fun to play with oil, right?

If you like wasting money instead of doing a proper diagnostic then sure.

 

[kschachn]

Not 50 grade. I ran a 15w40 (franken oil mix of Valvoline MaxLife 10w30 with VR1 20w50) and the car smoked worse than ever. I think the thicker oil ended up having longer residence time in the combustion chamber and/or just being thicker made it produce more smoke. Also I get spec oil pressure with the Valvoline Restore and Protect 5w30 so a 40 weight would not necessary be the best move, though I never checked oil pressure with the 40 weight in it. .

Yes I’m sure residence time in the combustion chamber was the problem.

 

[TallPaul]

If you like wasting money instead of doing a proper diagnostic then sure.

I guess I like wasting money. Went to the grocery store today. It is 4 miles away, but I went right past it to the one that is 9 miles away so I could drive the Mustang more.

Anyway, I am not averse to a piston soak but would want to do a bore scope first to see what things are looking like.

 

[maraakate]

Also, you'd be amazed at how many customers bring me bikes that claim it "runs like a top" and it's only been firing on one cylinder while leaking gas into the other.

"It's cold blooded to start, but they're all like that. Once it's idling and you leave the choke up a bit, it run's great"

 

[maraakate]

I guess I like wasting money. Went to the grocery store today. It is 4 miles away, but I went right past it to the one that is 9 miles away so I could drive the Mustang more.

Anyway, I am not averse to a piston soak but would want to do a bore scope first to see what things are looking like.

Do a real diagnostic. You're just going to chase your tail. What is so hard about doing a leak down test?

 

[OVERKILL]

I don't know that the valve guides are an issue. Wouldn't that cause a puff on start up after it leaks down the guides after sitting? That does not happen. It is always on acceleration, which to me suggests rings, but since it has great power, it must only be the oil control ring, and primarily that one cylinder. No other cylinder has fouled. The smoke is focused on the left tailpipe too.

You need to do a compression and leak-down test. The ECM does have the ability to run a cylinder balance test, I can give you the instructions for it if you want.

These engines are notorious for the PCV screen/filter under the PCV valve on the back of the intake getting packed solid with carbon and then they drink oil. If you've never changed that out, I'd pull it out and take a look at it.

If the PCV is fine, then that cylinder is probably scored, which will show up in both a leakdown test and compression.

 

[TallPaul]

Do a real diagnostic. You're just going to chase your tail. What is so hard about doing a leak down test?

Maybe the next time it is in the shop. Also a compression test. But seriously, the car runs strong so I am not sure it matters that much. Personal preference IMO.

AI says,
"Readings between 26% and 40% leakage are considered "fair" and are usually accompanied by reduced performance. Anything above 41% indicates serious problems that prevent the engine from performing as it should."
Maybe that one cylinder has reduced performance but you would never know it by the way she moves out. Also, a fouled plug did reduce performance.

Hot Rod Mag says,
"We talked to racers whose engines had leak-tested at 40 percent—and then they went out and set a new record."
https://www.hotrod.com/features/leakdown-lowdown-january-1987-982-1320-90-1

I just don't see a dire need for a leak down test, compression test, or even a bore scope. It will be more a curiosity, though it would be interesting to see what are the results. But, even i the cylinder has 50% leak down I am not going to have the engine rebuilt. I can buy a whole lot of oil and put the rest of the cash in the bank by not paying for a rebuild, and still have a ton of fun driving this thing. What if the shop does the tests and say the engine will eventually self destruct if you don't do a rebuild. Well then, let her self destruct, then the rebuild can be done with performance aftermarket block. All the better. As I see it I cannot lose in this situation.

 

[ThirdeYe]

Welcome back @TallPaul. I tend to take some long hiatus as well. How’s the ketchup stash?

 

[TallPaul]

You need to do a compression and leak-down test. The ECM does have the ability to run a cylinder balance test, I can give you the instructions for it if you want.

These engines are notorious for the PCV screen/filter under the PCV valve on the back of the intake getting packed solid with carbon and then they drink oil. If you've never changed that out, I'd pull it out and take a look at it.

If the PCV is fine, then that cylinder is probably scored, which will show up in both a leakdown test and compression.

I changed the PCV screen. Old one was packed solid. The new screen did not reduce oil consumption. What ever is going on in the cylinder can't be too bad if it is putting out good power. I think the oil control ring is the main culprit.

 

[TallPaul]

Welcome back @TallPaul. I tend to take some long hiatus as well. How’s the ketchup stash?

I don't keep a lot of ketchup anymore as too much gives me heartburn, but I do like my ketchup! It is good on mac and cheese too!

 

[ClutchDisc]

Main thing is no rebuild or anything like that is happening for now, it doesn’t get driven that many miles, so consumption isn’t a huge issue here. So for now, it’s running well and that is what matters.

 

[OVERKILL]

I changed the PCV screen. Old one was packed solid. The new screen did not reduce oil consumption. What ever is going on in the cylinder can't be too bad if it is putting out good power. I think the oil control ring is the main culprit.

Even if the oil control ring was packed solid, you still wouldn't be consuming this much oil. When we tore down my buddy's high mileage (>200,000 miles) HO, that had like no oil pressure (~12psi on 20W-50), we found all the oil control rings were plugged solid. It didn't consume anywhere near as much oil as you are.

Another HO we tore down (bought the car with the engine known bad) was like yours: #8 was a disaster, fouling plugs, drinking oil, it had some rather major scoring in the bore, which, IIRC, was due to a broken ring, though I may be misremembering, it's been a while. And yes, it still ran strong, just like yours does, which is why I suspect that there's damage to that hole unfortunately.

 

[TallPaul]

Heard AI says. Im done. good luck promptard

It links to
https://nasaspeed.news/tech/engine/how-and-why-to-do-a-cylinder-leakdown-test/
So not just garbage AI

 

[Japanese]

I thought about the piston soak option but seems there is a possiblity of creating a nasty sludgy mess in there that could be counter productive at least initially but hopefully would blow out. Sometimes I think it is best to go gently with this, nothing drastic. She's runing great and that is what really counts for me. Adding oil gives me a chance to play with oil more anyway. And it is always fun to play with oil, right?

Here, a recent report by a Valvoline Restore and Protect and B-12 user. His oil consumption in Audi Q7 was 1 qt every 400 miles. Now he doesn't burn any oil even at 5,000-6,000 miles.
https://bobistheoilguy.com/forums/threads/valvoline-restore-and-protect.381635/post-7558766

 

[Duukt]

My GS350 burned a quart in 300 miles on the highway at one point. It took two Valvoline Restore and Protect changes of 5K each to take it back to not burning at all. I didn't feel any change in power generation.