Does synth's base oil make engines run cooler

[VaderSS]

quote:

---

my mileage has actually decreased. temperatures have been unusually hot here in mi, so there has been lots of a/c on, and i sat for a while at the airport waiting for my wife's flight to arrive, but all my mileage numbers have been down somewhat.

---

Well, the heat will certainly reduce mileage. Also, do you have summer reformulated gas in your area? That will knock your mileage down right there. I've never heard of synthetic making negative impact on mileage when the same viscosity was used. Especially with Mobil 1 since it runs thin (within its rating) anyway.

 

[MolaKule]

tweeker, " i have a feeling i will be going back to the valvoline durablend on the next change. " Durablend is a blend of Group II dino and Group III dino oils.

 

[tweeker43]

molakule: it's what i used during break in. it has decent flow/flash numbers, it's half the price of mobil1 (which i used for 60k of 80+k miles on my last car). i was running mobil1 to the 7500 mile change, but it's really more cost effective (and comfortable) to run to 5000 with the durablend. i went through the msds, and yeah, it's II & III oil, with about the same percentage of 64742-54-7 as the valvoline synpower, which is also a fake synthetic. does fake synthetic make any sense?

 

[Patman]

Hehe, I used the term fake synthetic the other day when describing Castrol Syntec to someone! It is kind of a funny thing to say isn't it?

 

[MolaKule]

tweeker, "i was running mobil1 to the 7500 mile change, but it's really more cost effective (and comfortable) to run to 5000 with the durablend. i went through the msds, and yeah, it's II & III oil, with about the same percentage of 64742-54-7 as the valvoline synpower, which is also a fake synthetic. does fake synthetic make any sense? " Sure does and I can see the economics. It just gets my crank all twisted when I see Group III touted as synthetic fluid at synthetic prices. Fake synthetic is overpriced and overstated, in my view. Do you have any analysis reports?

 

[tweeker43]

molakule: here are the numbers between valvoline synpower and durablend. sorry the formatting is craptacular. durablend: Ingredient(s) CAS Number % (by weight) -------------------------------------------- ------------- ------------- HEAVY PARAFFINIC PETROLEUM DISTILLATES 64742-54-7 54.0- 64.0 SOLVENT-DEWAXED HEAVY PARAFFINIC PETROLEUM D 64742-65-0 10.0- 20.0 ZINC COMPOUNDS 68649-42-3 1.0- 1.0 synpower: Ingredient(s) CAS Number % (by weight) -------------------------------------------- ------------- ------------- PETROLEUM HYDROCARBON 64742-54-7 52.0- 62.0 ZINC COMPOUNDS 0.7- 1.4 the base oil is essentially the same, at half price. you might get more or less zinc with the "synth." vaderss: the winter gas up here really sucks. normally my mileage goes up a lot in the summer. i don't know if we have something new up here or not. i keep my tires inflated, etc... on the other hand, my mileage since the synthetic is down about 1mpg, and i've made a high speed interstate trip, my normal 30 mile one-way highway commute, and a bit of around town driving. pretty much a/c on constantly.

 

[dragboat]

Dated 1992 Redlines Chief Chemist states a 10 percent difference in heat transfer between a Synthetic and a Mineral http://www.vtr.org/maintain/lubricants-redline.html#synthetics

 

[MolaKule]

They must be averaging due to the total formulation; the convection and conduction figures, so 20% + 13%/2 = approx. 16.5%; derate total formulation by 6.5% for additive package, and you would have about 10%. I wish he had quantified the statement a bit more. Here is an experiment that might show the temp difference in synth's vs. dino oils: 1. Take a journal/bearing and turn journal with a motor that runs at constant RPM (say 1800 rpm) with load (flywheel) at the other end. 2. Pressurize the journal/bearing with oil pump with about 15-20 psi of oil in question, or just enough to overcome atmospheric pressure. Bearing must have an oil in and out ports (drill holes) with oil lines going in and out. Place a small radiator (8" x 10") in front of fan to simulate heat rejection by oil in engine, and circulate oil through this small radiator, using oil pump pressure above. Provide a small, but insulated sump to measure (oil return) sump temperature. 4. Place a sensitive thermometer in the input (pressurized) line to the bearing and measure temp in. Let journal get up to speed and measure at time intervals of say 1 min, 3 min., 5 min, 15 min, 30 min, etc. Run with Maxlife, Scheaffer's, Amsoil, Mobil, or whatever and measure temps. Chart in/out temps of each type of oil. Make sure previous oil is cleaned from system before next oil is tested. Same viscosity and type of oil (multi or straight grade) must be used to compare apples to apples. Publish results. WDYT?

 

[Don Stevens]

This is an interesting thread. Being a synth oil advocate I tend to like Molakule's argument about thermal conductivity. Here is my story of anecdotal evidence. I had a 1981 Porsche 911 (air cooled, small capacity oil cooler)that had about 125,000 miles, was getting a little tired, and was running hot on Castrol GTX 20W50 oil. HAbout 220F, and up to 250F on the factory gauge. I installed a larger oil cooler and fan which delayed the temperature creep up to 220F but would not stop it. Further, my experience was that once it got to 220-230F it would not cool down with easier driving even with the fan on the cooler. The oil seemed to act like a heat sink and the only way to cool the car down was to shut it off. I switch to Amsoil 15W40. The creep up to 220F seemed to take longer than the Castrol (yes I know it was a different viscosity). More importantly in my mind though was the fact that the car would cool down (I seem to remember about to about 200 to 210) if it was driven less agressively. This combined with the fact that in the back of my mind I knew that the thermal stability of the Amsoil was superior to the GTX I no longer cared when the oil got up above 220F. This change made a big difference in my peace of mind factor in our Florida heat. For the record, my mechanic bought the car from me nearly three years ago knowing that he could rebuild the engine much less expensively than I could have it done. The car has well over 200K daily driver miles on it now (he has used either Amsoil or Mobil-1) and he has never opened it up. Does this mean that synth base oil transfers heat better? No. Could Schaffer's have performed just as well? Maybe. But I didn't know then what I know now and at the end of the day it may not have mattered. I believed the advertising well enough to give the product a try and it worked for me. Don Don

 

[BOBISTHEOILGUY]

I don't think you'd experienced much difference if you had stayed with the same viscosity as that right there would definitely without any doubt change the temp due to the fact the flow of one is different than the other. The other point missed is that the antiwear/friction modifier additives between the two oils(syth/non synth) are not exactly the same, given that, can you actually contribute the difference because of the base oil or maybe the difference in the friction due to the additive differences? My point is, there is no proof anywhere that in an engine, the synth base oil itself is what makes the difference in cases like yours since there is no constant with the ep/fm additives which can vary temp very easily. This I can prove as I have done this on my timken machine. When taking a oil for example like m1 supersyn, the friction it is producing while shearing the base stock gets so hot you cannot hold/ touch it BUT, when applying moly, the friction immediately drops and temp drops back down. As of yet, I have not seen where base stocks actually carry off the heat any better in an engine because the design won't allow it. One other point, we have a moly based mineral oil, have changed to the blend (combination of mineral and PAO), and in some cases have gone the reverse. In any case, there has been no difference in any temps that are even slightly noticeable. Now when I get a new customer to try the Schaeffers, and say they have been using an oil not as equipped to reduce friction due to less antiwear/fm additives, I have seen it drop. I have a couple of race cars that have told me the same as some individuals, but never, have I had anyone make any comments when switching between our blend and mineral. The theory looks good, but in an engine, I don't agree with Molakules #'s IMHO.

 

[MolaKule]

Bob, Regarding the Proposed Test: That's why I gave (above) what I believed to be a fair test of what it would take to measure oil temps. It would be better if two different people were to make a small test setup as I have described above and compare their results. I wish I had the time to do it, but I do not right now. The test would show, I think: 1. Dinos MAY run hotter, or 2. Synths MAY run cooler, or 3. synth's MAY run hotter, or 4. Dinos MAY run cooler, or 5. Within the test apparatus and within measurement constraints, there WAS a measured difference in temps between the oils, but it was not significant, or 6. Within the test apparatus and within measurement constraints, there was no perceptible difference in temp. Regardless, this is one possible way to support or disprove the thermal calculations.

 

[BOBISTHEOILGUY]

It would prove if one oil brand vs another disperses heat better. The main issue was "Does synth's base oil make engines run cooler than a dino's base oil in the same engine under normal conditions?" The problem is that we would not test base oils but, motor oils. I guess if we had access to nothing but base oils it would work but The point I was going for is that people are stating that synths cool better. Is it the base oil or maybe the additive package, Like the statement of certain oils "condition" seals because of the esters again, I have seen no evidence of that as well. The fact that I have seen how if you swap different schaeffers oils in one engine, blend to mineral, mineral to blend, and not really seen much difference in extended drains, wear #'s and temp differences, but all of which are using the same basic additive package,(there is a slight difference between the mineral and blend's additives) but overall, generally the same, leads me to believe that when so many stress the base oil as the determining factor of how good an oil is, we should be examining the additives and the blending of such. Of course the base oil does provide a good base to start with(thats a given) Example, Having looked at the maxlife additive levels on paper, told a good story, very low detergents, IMO, would not allow for longer drains as it would tend to oxidize faster due to acids not being cleaned up. Patmans test seems to support that in 2300 miles. Redline,even though it's a full synth, tends to oxidize faster than it should, not allowing it to extend drains as much as some other full synths. why? over load of zinc/mo maybe, causing a fight between the two? Bror's analysis as well as a few others I've seen seems to support that. Amsoil, has high levels of detergents, given a 12tbn, will allow it to fight acids longer thus a better and longer extended life and with higher levels of zddp, more antiwear protection.. but, now after running analysis on many, you find it in comparision that the tbn seems to drop faster than some others in same conditions, why, maybe lower antioxidants? still a good oil. Some other tests I've seen doing comparisions awhile back seems to support that. Not to mention you need to justify costs just for these higher priced full synths. So what is it that does that? Extended drains, but base oil alone doesn't set the extended drain interval capablility of an oil but additives will give you a better picture to some degree. The point is, with a virgin sample of the oil, it really can tell you how it would tend to hold up in an engine more so than just looking at flash points and such. Also, I believe that when looking at the FM/EP additives, it too will tell you how it will provide better temp control as this is what will prevent friction which is one of two things that actually causes heat. The other one a constant developed from the combustion area.