High Mileage Oil Vs. Mobil 1 Synthetic

[BOUNDER]

question

I don't understand the mechanics/engineering behind this, but could the stock/factory oil pressure gauge in the 80 LC originally calibrated for dino oil be misreading the new synthetics? I too noticed my OP gauge riding lower than normal after changing to Mobil 10W30 semi-synth - and the NAPA Gold 1515 filter. Is there such a thing as a newly engineered aftermarket gauge or oil filter for synthetics - or am I just being silly? Wondering what the gauge is like in an '05 Mercedes SL 600 V12, for example. I believe M1 is used from the factory.

 

[RavenTai]

Same here when warm,

When cold it shoots to the 3rd mark on start (relief pressure) and sits until it warms up

This behavior jives with how oil, oil pumps and relief vales interact.

If yours is not doing so I would connect a mechanical gage and confirm.

 

[Jim_Chow]

I was using Rotella T synthetic & Delvac 1 and tried M1 10w30. It merely dragged my fuel economy down by 5% in both vehicles (one is a newer honda, then my 86 toyota truck). I switched back to Rotella T syn and Delvac 1.

 

[e9999]

a pressure gauge like this would normally measure the pressure directly though some mechanical device (diaphragm, spring, piezo etc), so it wouldn't be "misled" by a different oil. Just reads a different pressure...

 

[tarbe]

It's all about the viscosity of the oil you are using...not whether it is dino or synthetic.

Mobil 1 10W-30 often shears to about 9.5 to 9.8 cSt and will always register lower pressure than say Shell Rotella 5W-40 which is closer to 15 cSt (all at 100C).

When I run a 15 cSt (Schaeffer's 15W-40) oil my gauge is at the third mark or even just a touch above at 2400 rpm. With a 10 cSt oil (various 5W-30) it is halfway between 2 and 3.

With a thick 5W-30 (Valvoline MaxLife synthetic which is 11.5 cSt) it is just below the third line.

Remember - it is not pressure that lubes your engine, it is FLOW! Abnormally high pressure could result from poor flow ie, very viscous oil or blocked passages.


Higher flow also cools your engine better...GO with the flow!

Not to mention a 15cSt oil makes my Cruiser a slug....well, more of a slug!

 

[RavenTai]

a pressure gauge like this would normally measure the pressure directly though some mechanical device (diaphragm, spring, piezo etc), so it wouldn't be "misled" by a different oil. Just reads a different pressure...

nope, pressure is pressure, as long as the fluid is not to thick to flow you will get the same reading for a given pressure weather it be 0w20 or 20w70

 

[e9999]

nope, pressure is pressure, as long as the fluid is not to thick to flow you will get the same reading for a given pressure weather it be 0w20 or 20w70

unfortunately not, RT, you will get different pressures with different viscosities at the same flow rate. So it is really a function of the head / flow curve of the pump, i.e. what it can provide. But typically, higher viscosity will get you a higher pressure and lower flow rate (unless it is a true positive displacement pump with no leakage).

 

[Aseif007]

Have you guys ever noticed the difference in oil pressure when you use the old style coffe can Toyota oil filter vs. the new "supposedly better" smaller Toyota filters? I get higher oil pressure readings at idle with the old style big filter. What kind of filters are you guys using when you see the lower idle oil pressure? And has anyone ever used Swepco oil?

 

[RavenTai]

unfortunately not, RT, you will get different pressures with different viscosities at the same flow rate. So it is really a function of the head / flow curve of the pump, i.e. what it can provide. But typically, higher viscosity will get you a higher pressure and lower flow rate (unless it is a true positive displacement pump with no leakage).

Sorry E I miss read your post (replace wouldn't with would), and I believe you have mis read mine, I think you missed the “for a given pressure” part.

I thought you were saying that the oil pressure sender would read differently for the same actual pressure depending on oil type. Witch would not be correct

After re-reading your post and the one above I see you were not saying that.


Yes oil pressure changes with viscosity weather it be from how the oil is made or viscosity changes of the same oil through temperature. The 80’s oil pump is positive displacement but it has a relief valve. Flow follows RPM of the pump up until relief pressure it hit after that flow rate is determined by how much oil flows out of the parts.

Thicker oil does not get squeezed out of bearings as fast so the flow rate is less but it also provides better protection as it takes more load to squeeze it out allowing metal to metal contact

 

[RavenTai]

Have you guys ever noticed the difference in oil pressure when you use the old style coffe can Toyota oil filter vs. the new "supposedly better" smaller Toyota filters? I get higher oil pressure readings at idle with the old style big filter. What kind of filters are you guys using when you see the lower idle oil pressure? And has anyone ever used Swepco oil?

I use the small 20004's and the oil pressure is the same as with larger filters. Bigger oil filters are generally better for a lot of reasons but Toyota decided for some reason to mount the filter horizontally witch changes things, now it can drain, when a filter is empty a smaller filter is better on start up.


Witch small filter are you using? If you are seeing better oil pressure with the larger filter I would stick with it.

If you are using 20004’s I will gladly properly dispose of the remaining evil oil pressure robbing devil’s for you.

 

[Aseif007]

I have used the 90915-YZZB5s on my FZJ and my 3FE. Now I have 15600-41010 on both. I like the old filters, but I am open to suggestion. What is the part number for the small good filters? 90915-20004? Thanks

 

[e9999]

basically, this oil pressure gauge is a very crude instrument that does not tell you much about lubrication. Depending on where the sensor is located wrt to the pump and the critical areas to be lubed it may or may not tell what's going on. A low pressure could mean high flow rate in big passages but low flow rates in tiny passages. A high pressure could very well mean indeed that the passages are clogged etc.
I guess basically the usefulness of the gauge is entirely on a relative basis. IOW showing sudden and therefore likely dangerous changes. Probably the main thing it can be relied on is that if it goes to min or max it tells you to shut down the engine and have things looked at ASAP...

 

[tarbe]

I just want to caution anyone against generically thinking that higher pressure is always better. It is not.

Because one filter sets up higher pressure than another (all else being equal) also means it is allowing less flow. This could be ok (finer filtration with adequate flow) or it could be bad (inadequate flow regardless of filtration).

As e9999 said above, these gauges are useful for relative comparison or to note an acute problem, but that's about it.

 

[RavenTai]

Because one filter sets up higher pressure than another (all else being equal) also means it is allowing less flow.

That may have been true if the pressure was picked up before the filter but the 1FZ senses oil pressure after the filter, in this case all other things being equal higher indicated pressure is a less restrictive filter,

 

[tarbe]

Right RT, more restrictive filter = less flow and greater pressure drop. I was not careful in my construction. Most pressure gauges are after the filter (if not all?).

My primary concern is dealing with the general belief that higher pressure is alway better. High pressure can be obtained at the expense of flow and that is always undesireable. Of course, this happens for awhile each time we perform a cold start!

 

[erics_bruisers]

I just switched my '87 over at 235K -- M1 in the engine and diffs --

-- again, not a hiccup --

 

[Hayes]

I've been using Valvoline MaxLife dino (10w30, 5w30 winter), which has had decent reviews on bobistheoilguy.com. While some folks criticize the notion of "seal swellers," I haven't read any actual reports of damage or harm from using them. I'm assuming it can't hurt, and might actually be beneficial. I don't consume any measureable (with my crude methods) amount of oil in 4k miles.

While I certainly understand and aknowledge the benefits of synthetics, I've avoided doing the Mobil 1 thing because of common reports of leaking and consumption, as well as the cost.

I think if I decided I could justify the cost of synthetic motor oil, I would go with the MaxLife synthetic--which has had excellent reviews on bobistheoilguy--and get the best of both worlds.

Hayes

 

[Mike S]

I have never seen the reason for high mileage oil. I believe that it may help sell more oil ata better price?

I use 5-30 M1 in my Ford Expedition (since new - now 130K and strong), used M1 10-30 in my 60 (170K and strong), and will out M1 5-30 in the new to me 80 (110K) parked in the driveway now. When I bought the 60 and swapped over to M1, I did get a little leakage from the side cover, which was easily fixed. No more leaks since then.

I notice that many of you are using higher viscosity oils than are recommended by Toyota for your 80 series trucks - the manual says 5-30 is the 'ideal' weight. What's the thinking on hogher viscosity numbers?

I have run Mobil 1 in my cars and trucks for a long time. It is really the best thing you can do for your engine.

M

PS: Those "little filters" work very well! I run WIX in the Ford, but Toyota 'little' filters in the cruisers.

 

[drsales]

Switched mine over @175k. Runs great and my Blackstone analysis was A1. Now at 186K I use about 1 qt in 5k. They suggest going for 6.5k on this next change.

Give it a try.