Hi all-decided to see what all the heavy oil hype was about and tried it in my 1997 Dodge B2500 van which is a Roadtrek motorhome conversion with a 5.2 (318) engine. Mileage is about 140K and I have always run 10/30W as per specs. I use a Scanguage II to monitor performance. Decided to use 10/40 for the summer months thinking it would offer a little more protection. Usual operating temperatures are around 198 degrees which climbs when pulling mountain grades. Oil pressure is noticeably higher (3/4 on the analog gauge instead of the usual 1/2 way) and temps seem to be consistently higher. Today when pulling a long 6 mile grade up the mountain, the temp rose to 215-218 instead of the usual 204-206. Does the heavier oil (Valvoline MaxLife 10/40) really make that much of a difference???
Heavy oil=hotter temp?
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I sure love the ScanGauge.
Originally Posted By: chartrue2
Today when pulling a long 6 mile grade up the mountain, the temp rose to 215-218 instead of the usual 204-206. Does the heavier oil (Valvoline MaxLife 10/40) really make that much of a difference???
Yes.There is a difference.
Maxlife 10W40 is 13.94 cSt at 103*C; and
Maxlife 10W30 is 12.00 cSt at 95*C, despite being 8*C cooler.
One vote goes to lower operating temperature..... but at reduced oil film thickness ?
Oh no, 10*C higher temperature in 10W40 would half the oil life of 10W30!!!...... according to experts.
Then OCI 10W40 at 10k and compare against 10W30 OCI at 20k UOA ...... or
OCI 10W40 at 15k against 10W30 at 25k ...... and compare.
Do you need extra thick oil film thickness from 10W40, albeit at higher operating temperatures ?? .........
that's another topic for debate..
Btw,it would be interesting for OP to demonstrate if xW20 operates cooler than 10W30?
Originally Posted By: merconvvv
Found this figure in lubetech article.
Seems like after 30 wt there is very little to gain.
Concur with you, in gasoline engine applications ONLY.......
probably not .. in differential gear or hydraulic applications..... vis-a-vis thick vs thin oil comparisons.
Edit: Add info.
Today when pulling a long 6 mile grade up the mountain, the temp rose to 215-218 instead of the usual 204-206. Does the heavier oil (Valvoline MaxLife 10/40) really make that much of a difference???
Yes.There is a difference.
Maxlife 10W40 is 13.94 cSt at 103*C; and
Maxlife 10W30 is 12.00 cSt at 95*C, despite being 8*C cooler.
One vote goes to lower operating temperature..... but at reduced oil film thickness ?
Oh no, 10*C higher temperature in 10W40 would half the oil life of 10W30!!!...... according to experts.
Then OCI 10W40 at 10k and compare against 10W30 OCI at 20k UOA ...... or
OCI 10W40 at 15k against 10W30 at 25k ...... and compare.
Do you need extra thick oil film thickness from 10W40, albeit at higher operating temperatures ?? .........
that's another topic for debate..
Btw,it would be interesting for OP to demonstrate if xW20 operates cooler than 10W30?
Originally Posted By: merconvvv
Found this figure in lubetech article.
Seems like after 30 wt there is very little to gain.
Concur with you, in gasoline engine applications ONLY.......
probably not .. in differential gear or hydraulic applications..... vis-a-vis thick vs thin oil comparisons.
Edit: Add info.
Last edited:
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Originally Posted By: zeng
Btw,it would be interesting for OP to demonstrate if xW20 operates cooler than 10W30?
This is what I'd like to see.
Btw,it would be interesting for OP to demonstrate if xW20 operates cooler than 10W30?
This is what I'd like to see.
Yes a higher viscosity oil will raise oil temps a bit, no real point in putting in a 10W-40 in the summer really.
Anyway even at 218F you are still in "the safe zone" but i would recomend you either run a 10W-30 or 5W-40 full synthetic oil.
Anyway even at 218F you are still in "the safe zone" but i would recomend you either run a 10W-30 or 5W-40 full synthetic oil.
Does it have a clutch fan ? Maybe it's time for a dual electric fan conversion ...
Originally Posted By: merconvvv
Found this figure in lubetech article.
Seems like after 30 wt there is very little to gain.
Be interesting to see how the 10w40 does when the weather cools down a bit. Imagine its hot all over.
Depends entirely on the engine in question. Some new cars spec 50
Found this figure in lubetech article.
Seems like after 30 wt there is very little to gain.
Be interesting to see how the 10w40 does when the weather cools down a bit. Imagine its hot all over.
Depends entirely on the engine in question. Some new cars spec 50
No discussion of upper ring temps? Long history here on BITOG...
http://www.lube-media.com/documents/cont...ndlubricity.pdf
Thats the article. I am not an oil expert. I just thought it was interesting. Anyways what iiii gather is that beyond hths of 3.3 or so minimal gains are to be had.
Then you have to add a safety margin to that 3.3 or so.
Thats the article. I am not an oil expert. I just thought it was interesting. Anyways what iiii gather is that beyond hths of 3.3 or so minimal gains are to be had.
Then you have to add a safety margin to that 3.3 or so.
Shannow posted excerpts from a study showing the power losses due to oil thickness for a street and a racing engine, a thicker oil will naturally result in a greater loss than a thinner oil under the same operating conditions and the result is hotter oil. I noticed this in my own car when I switched from M1 5W30 (HTHS=3.1) to M1 5W30 ESP (HTHS=3.58) and was alarmed enough to post here asking what was going on...it totally makes sense when you think about it, though.
Shannow also mentioned that the increased temperature will not result in the thicker oil having a lower film thickness than the thinner oil under the same circumstances, there would be no point in using the thicker oil if that weren't the case.
Shannow also mentioned that the increased temperature will not result in the thicker oil having a lower film thickness than the thinner oil under the same circumstances, there would be no point in using the thicker oil if that weren't the case.
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