Motor oil question: Delo Diesel 5W-40 synthetic in a gasoline car? - Page 2 - PeachParts Mercedes-Benz Forum

tjts1 · #16 09-12-2014, 02:23 AM

Quote:

Originally Posted by upshift

I've heard of that controversy and have done my research. The older modular motors called for 5w30. This was before 5w20 was commonplace. The simple answer is that the motor was designed for thin, 20 weight oil, and thicker oil actually accelerates engine wear in that motor. I've talked to Ford engineers, city fleet managers, and have owned probably 15 Ford modular v8s. I've heard personally of two oil related failures: chain guides worn out after running 15w40 for 50,000 miles and 75k miles - separate cars.

And yet Ford Australia never stopped recommending 10w30 on the modular engines, long after the US went to 5w20. Can you imagine the millions of broken Ford V8s they must be dealing with? Maybe we should tell them about CAFE and how they're killing the penguins and what not.

Simpler=Better · #17 09-12-2014, 10:14 AM

Not with that engine, but with a Ford 2.3 (timing belt drivbes the oil pump...) I run whatever is on sale. 5-20, 10-30, 15-40, straight 30, etc. 60k of doing this and no problems.

I tihnk changing it regularly is more important. FYI, the place that sells rock bottom ford parts has wix 51515 filters for something like $5.20/pc when you buy a 12 pack.

Idle · #18 09-12-2014, 12:42 PM

Quote:

Originally Posted by aklim

What exactly does "wore out" mean? How did the mechanic determine what was wrong? Was a teardown done?

I just pulled off the valve covers of my GM 350 L98 motor. The holes are pretty large (at least 3/8 inch if I am viewing it right)

Doesn't say much. Without a teardown, how would anyone know why it failed and how the oil helped?

Prior to my friend taking the car to a mechanic he asked me to listen to it since it had 'a noise'. I figured perhaps a water pump or harmonic balancer. Maybe a lifter.

Nope. It was pretty clear the crank bearings were hammered.

Like I said: I don't know much about Fords and don't really care to. I was only repeating what I was told.

Idle · #19 09-12-2014, 12:43 PM

Quote:

Originally Posted by aklim

Only way you can tell besides anecdotal "evidence" is if you have other engines outside and they are dirty and this one is clean.

Yawn......

Zulfiqar · #20 09-12-2014, 01:09 PM

Quote:

Originally Posted by Idle

I knew a guy that wore out his Mustang motor in 72,000 miles. The mechanic told him he was using the wrong grade of oil.

According to the mechanic (and I don't know much about Fords so I am just repeating what I have been told) the oil return holes in the heads are too small for the higher weight oil to run though at a speed needed to supply the oil pump. Therefore oil tends to get trapped on top of the heads and is not getting back to the oil pan fast enough to be pumped in the correct volume.

He started using the correct grade of oil and after nine years he still has the same used engine that was installed to replace his original.

Isnt this more true of Nissan engines like the CA18 and RB25 - their oil drain holes were the size of pencils

aklim · #21 09-12-2014, 01:13 PM

Quote:

Originally Posted by Idle

Prior to my friend taking the car to a mechanic he asked me to listen to it since it had 'a noise'. I figured perhaps a water pump or harmonic balancer. Maybe a lifter.

Nope. It was pretty clear the crank bearings were hammered.

Like I said: I don't know much about Fords and don't really care to. I was only repeating what I was told.

I suspect what you were told was simply jumping to conclusions if there is no proper analysis done.

aklim · #22 09-12-2014, 01:13 PM

Quote:

Originally Posted by Idle

Yawn......

Sorry, I didn't take Voodoo and Ouija Board 101.

barry12345 · #23 09-12-2014, 01:38 PM

I had wondered why engine recommendations had gone to 0-20 synthetic on our Toyota in Canada.. At first I suspected that material finishing and tollerances had vastly improved. They have to some extent I suppose.

That did not make total sense to me either. There was a chance that the old expression that most engine wear occurs at start up may have been true. The lighter weight oils will get into clearances faster has to be a given if so. Can the oil separation barrier be as effective though when hot?

Engines will not break in on synthetics. Do they have some form of additional inherent protective ability in comparison to dino oil? I am starting to consider that synthetic oil may have a much larger molecular size composition compared to dino. .

For example if you are far from home and your water pump starts to leak. Dumping the anti freeze and introducing straight water may shut the leak. I have sen the reverse in the old days where installing anti freeze made both front water pumps start to leak. They had never even seeped with water in them.

The water is less slippery than anti freeze. I have thought it was because the water molecules are just much larger perhaps. It does probably work sometimes.

What I am thinking is that if the car specifies 0-20 synthetic do not put in a dino oil of the same viscosity scale. For example it may take a 10-30 weight dino to replace the protection effect of the larger molecules in the synthetic oil.

I hope someone on site can clear this issue up. I am just guessing.

aklim · #24 09-12-2014, 01:51 PM

Quote:

Originally Posted by barry12345

Engines will not break in on synthetics. Do they have some form of additional inherent protective ability in comparison to dino oil?

I am starting to consider that synthetic oil may have a much larger molecular size composition compared to dino. .

What I am thinking is that if the car specifies 0-20 synthetic do not put in a dino oil of the same viscosity scale. For example it may take a 10-30 weight dino to replace the protection effect of the larger molicules in the synthetic oil.

They won't? Why is that? There are more and more manufacturers sending out cars with synthetics which are more expensive. Wouldn't they benefit by that excuse to give you some cheap oil (for break in purposes and the betterment of your car) with that excuse?

IIRC, molecular size is standard for synthetics whereas conventional oil has different sizes.

Recommendations have been to stick with the weight of oil recommended be it synthetic or conventional. I don't think, and I might be wrong, but I don't believe synthetic oil manufacturers have told you to change the oil weight if you use synthetic, have they?

barry12345 · #25 09-12-2014, 02:50 PM

On a lot of cars the original oil in the engine from the manufacturer is dino or some form of oil mix. At the first oil change it is changed to the recommended synthetic.

That is just a guess by me on many brands. There is no reason to inform customers of this I can think of. Engines will not break in on dino is known. Actually this speaks well for synthetic oils one would think.

aklim · #26 09-12-2014, 03:43 PM

Quote:

Originally Posted by barry12345

Engines will not break in on dino is known. Actually this speaks well for synthetic oils one would think.

Known to whom? I hear urban legend but why would a manufacturer put it in if so?

w123fanman · #27 09-12-2014, 03:47 PM

While all this discussion is interesting, does anyone want to provide ideas on my previous question?

Quote:

Originally Posted by w123fanman

It's just that I have like 33 gallons of the stuff sitting in the basement. HE has decided to just go ahead and use 5W-20.

Which leads me to my next question: I have 3 MB diesels that don't leak or burn any oil that I could put it in:
my 190D with almost 320,000 miles now
my brother's 300SD with 181,000 miles
and our Sprinter with almost 185,000 miles now

We have ran conventional in my 190D the past 2 oil changes (10w-40 then 5w-40, 3,000 mile interval instead of the recommended 5,000 miles) but according to the PO, it was ran on synthetic Rotella.

The 300SD seems to have been ran on conventional by the PO and we have not changed the oil on it yet (haven't driven it much).

The Sprinter has been ran on synthetic Mobil 1 Turbo Diesel Truck oil (5W-40, changed at 7,500 miles instead of 15,000 miles as recommended by manual) since new. My understanding is that the Mobil 1 oil is a higher grade synthetic, but should that really even matter if we change that oil at half the specified interval?

INSIDIOUS · #28 09-13-2014, 09:52 PM

Quote:

Originally Posted by Idle

I knew a guy that wore out his Mustang motor in 72,000 miles. The mechanic told him he was using the wrong grade of oil.

According to the mechanic (and I don't know much about Fords so I am just repeating what I have been told) the oil return holes in the heads are too small for the higher weight oil to run though at a speed needed to supply the oil pump. Therefore oil tends to get trapped on top of the heads and is not getting back to the oil pan fast enough to be pumped in the correct volume.

He started using the correct grade of oil and after nine years he still has the same used engine that was installed to replace his original.

So then would too thick an oil show up as low pressure on the gauge (hot) and replacement with thin oils would increase hot temp pressure readings? edit, the reason I put that out here is the idea that perhaps in most cases of low oil pressure indication developing it is just that the old oil is gunking up, moisture or what not, and just needs changing and perhaps the viscosity was not the issue? Mechanical issues can be ruled out if a simple oil change rectifies the low pressure indications. Right?

aklim · #29 09-13-2014, 10:52 PM

Quote:

Originally Posted by w123fanman

While all this discussion is interesting, does anyone want to provide ideas on my previous question?

So far, all I can see is that it would hurt the fuel economy. Assuming it is approved for your weather, I don't see the issue. OTOH, if it gets too thick in the winter, it might be an issue

Skippy · #30 09-14-2014, 05:29 AM

Quote:

Originally Posted by w123fanman

While all this discussion is interesting, does anyone want to provide ideas on my previous question?

My 300D has essentially the same engine as the 300SD you're asking about. I've run it on 5W40 synthetic (Rotella T6) for about 35,000 miles out of its total 335,000. I change it at my earliest convenience after 3000 miles. This is probably excessive, but I haven't done oil analysis to determine a safe longer drain interval. I've had no oil related engine problems to date except for some weeping oil cooler lines that I changed out, and a filter housing to block gasket that got leaky after about 30 years. Delo should perform about the same.

You say the 190D has already been run on Rotella T6 without incident. Delo should do about the same.

The only one I would have concerns about is the Sprinter. Some newer vehicles spec very specialized oils to be able to run very long drain intervals. Less specialized oils should be fine as long as you change them sooner. Oil analysis will give you a better idea of how much sooner.

Aren't you at Tech now? If so, wander around MRDC looking for a tribologist or two to discuss this with. A fun and informative (or possibly very confusing) conversation may ensue.