Heavier Summer Oil

[Motokan]

Yeah, another popcorn thread.

My POV is that provided the engine stays at design operating temperature there is no need to change the oil viscosity.

Typical CHT on street driving is 195F. Monitor that and so long as it stays that temp on cold or hot days then there is no need to change oil weight. Many of us run 5w30 full synthetic for this scenario.

Furthermore I use 12cs viscosity for preferred viscosity. IIRC this is 20wt for street driving. On track my CHT runs 230. 40wt is 12cs at that temp. So I run Mobil 1 0w40 Euro oil from the 12qt box on track. If I think I can get through a full oil cycle between track events then I will put 30wt back in.

No sir forget

Hello; Oil??? Back when I first knew of oil I think it was mostly straight 30 weight. I used it in lawn mowers. The old sort with no safety features. The sort you killed the engine by pushing a metal grounding strap over onto the exposed spark plug. No other practical way to stop it from running.
The first multi weight I used was 10-w-30. That was the go-to oil for a long time. Thin like 10 weight oil when the engine is cold. Additives in the oil caused it to thicken to 30 weight as it got warm and then hot.
(NOTE- this was the reverse of how most liquids, including oils normally work. pour a dab of Canola oil in a cold skillet. Try tilting the skillet when clod and watch the oil. Then turn on a burner and let the skillet get warm to hot and tilt the skillet. The oil gets thinner and moves around easier.)
10-w-30 oil was a neat trick. That way you got effectively easier to move 10 weight oil when starting from cold. The 10 weight would course thru the engine easier at that crucial cold time. The oil only stayed at the thinner 10 weight for a little while. As the engine warmed up it got to a thicker viscosity which is good for crank & cam bearings, cam lobes and such.
Later on, 5-w-30 became more common. Both my current vehicles call for 5-w-30. They are over 20 years old. I can run 10-w-30 if the air temp is to be above freezing during the length of time I will be driving the vehicle. Back when I drove more miles I would change to 10-w-30 in the spring and back to 5-w-30 in the fall.

0-w-20 scares me a bit. 0-w-16 scares me a lot. Not so much the 0 since the oil will thicken soon and I can baby the engine till it gets warm. I do wonder about my neighbor who starts her car, drives the 75 feet to the major county highway and guns it to 60 MPH or better right away. I do wonder about the 0 part of oil if in fact her vehicle uses the stuff.
It is the 16 & 20 hot weight I think about. Does it really do the job well or is it part of the EPA and other such agencies squeeze placed onto manufacturers to squeeze max MPG's out of ICE engines in order to try to meet onerous fleet MPG standards.
(THANKFULLY some of those onerous standards are relaxed, at least, for a while.)

Ford changed Coyote to 5-w-30 a little while back is what I have been reading. My guess is to maybe prevent some ongoing engine problems. With the cam phasers and other things that work on oil I guess 5-w-30 is OK.
I already change oil at 3000 miles regardless of the labels. I am more interested in engine longevity than squeezing fractions of MPG's out. Working so far as my car is now 25 years old & my truck is 22 years old. An anecdotal observation at best. May well be my good looks at work.

My car has a timing chain is one reason I change oil at 3000 miles. I want the chain, tensioners and other overhead cam stuff lubed with clean oil.

To the question of the thread as I understand it. I would not change to a lighter weight oil for hot weather. The weight does not have much, if anything, to do with heat. My take is any weight will move heat. I do not know if a Mustang has an extra oil cooler built in from the factory. My truck does. Maybe having such an oil cooler added would be the way to go???

I have a feeling the stock setup and oil is good enough. Maybe not for track days or racing in Death Valley???

Gents, I heard the "heavier" oil stayed on the moving parts.
Longer than the "lighter" oil.
My question is legit. No popcorn needed.

My ride is a 2021 GT 5.0

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[robvas]

Gents, I heard the "heavier" oil stayed on the moving parts.
Longer than the "lighter" oil.
My question is legit. No popcorn needed.

Don't be silly, the heavier oil falls off faster because of gravity.

 

[EFI]

Contrary to popular belief, oil temps don't generally run hotter in the summer (or colder in the winter) while operating the vehicle. Sure summer air can be warmer, but the oil temps are controlled by coolant temps. And while coolant can run a bit hotter, it's not going to have a major impact on overall high end of temperatures for oil.

The Mustang doesn't need different weights oil if you're just driving down the street regardless if you're in Minnesota or Arizona. If that was the case then the manual would have stated so. So while temps may be hotter, it doesn't warrant a viscosity change.

Now driving hard, track use, boost etc. most definitely needs it, but that's not really the topic at hand today I think the OP was mainly concerned with summer street driving.

 

[2015 Silver GT]

I’ve been using olive oil with great success. It smells like I’m cooking out of my active exhaust. Longtubes should take it to another level.

 

[Motokan]

Contrary to popular belief, oil temps don't generally run hotter in the summer (or colder in the winter) while operating the vehicle. Sure summer air can be warmer, but the oil temps are controlled by coolant temps. And while coolant can run a bit hotter, it's not going to have a major impact on overall high end of temperatures for oil.

The Mustang doesn't need different weights oil if you're just driving down the street regardless if you're in Minnesota or Arizona. If that was the case then the manual would have stated so. So while temps may be hotter, it doesn't warrant a viscosity change.

Now driving hard, track use, boost etc. most definitely needs it, but that's not really the topic at hand today I think the OP was mainly concerned with summer street driving.

Yes thank you.
No track, just local. What I'd heard:
In summer when parked. The opinion was thicker will not drip off quick as thiner oil.
I'm just airing it out.
Popcorn or Italian virgin(Lol) not necessary

 

[EFI]

The opinion was thicker will not drip off quick as thiner oil.

The type/brand oil is far more important than viscosity when it comes to protecting engine parts after the engine is off and before the next start. Get a high quality oil that has good additives and that will do the job better than a thicker oil.

 

[Gen 6 Mach1]

I use Motocraft Full Synthetic 5-50w March thru September and 5-30w Oct to Mar.
Not sure where Masshole is, but living in the Central Arizona Desert April to September the ambient temperature range 85 / 95 April ,May to September 100/ 110 and above to 115 , I'll use 5-50w

 

[MAGS1]

Wait, you’re supposed to put oil in the car? Dammit, I knew I was forgetting something

 

[HoosierDaddy]

Wait, you’re supposed to put oil in the car? Dammit, I knew I was forgetting something

I don't change or put oil in all my cars. I do run heavier electrons in the summer, though.

 

[T Fades]

Contrary to popular belief, oil temps don't generally run hotter in the summer (or colder in the winter) while operating the vehicle. Sure summer air can be warmer, but the oil temps are controlled by coolant temps. And while coolant can run a bit hotter, it's not going to have a major impact on overall high end of temperatures for oil.

The Mustang doesn't need different weights oil if you're just driving down the street regardless if you're in Minnesota or Arizona. If that was the case then the manual would have stated so. So while temps may be hotter, it doesn't warrant a viscosity change.

Now driving hard, track use, boost etc. most definitely needs it, but that's not really the topic at hand today I think the OP was mainly concerned with summer street driving.

The type/brand oil is far more important than viscosity when it comes to protecting engine parts after the engine is off and before the next start. Get a high quality oil that has good additives and that will do the job better than a thicker oil.

I agree about the coolant impacts oil temp, but that isn't in play when the engine is cold. You don't want to run super heavy oil when its cold outside and the car is also cold.

I like to use what the viscosity the owners manual calls for.

IMO viscosity is WAY more important than the brand of oil. You can't be putting 0-16 in a v8 mustang.

 

[EFI]

but living in the Central Arizona Desert April to September the ambient temperature range 85 / 95 April ,May to September 100/ 110 and above to 115

Again whether the high is 15* where I live or 115* where you live, the oil temps driving around normally will be within 10-15* at full operating temps. That doesn't warrant the change to w50 just for the temperature alone, maybe going up to w30 but certainly not to w50. Now if you're beating on it or racing constantly in that Arizona weather sure, going up in viscosity will help because the oil temps will be much higher.

FWIW, I personally use a 5w50 when road racing in the summer. I'm a firm believer in thicker oil for higher temps. But to putt around on the street you don't need anything more than a 5w30 even in Arizona.

 

[EFI]

IMO viscosity is WAY more important than the brand of oil. You can't be putting 0-16 in a v8 mustang.

I meant that in regards to the popular choices that people change to, of course no matter what oil a 0w16 is never a good idea. But a high quality fully synthetic 5w20 (Amsoil, Motul, PUP etc.) will protect far better than a generic brand 5w30 or 5w40 even at high heat.

 

[sk47]

In summer when parked. The opinion was thicker will not drip off quick as thiner oil.
I'm just airing it out.

Hello; you bring up a second question or maybe this was your concern all along. There is an industry around treatments which "soak" into metal "pores".
I have seen clever promotional videos of things advertised to penetrate into metal. The ads look convincing. Z-Max is one such additive. The thing is I have not set up any sort of test for their claims. What i have done is to try the additive in my now 25 year old Nissan Sentra with the 2.0 l engine. Near 149,000 miles. I have added the stuff twice now during what has become my yearly oil change. ( i do every 3000 miles or once a year). I have not had the engine apart so cannot say how things look. That said since I did not have a look inside before trying the additive I have nothing to compare.
I have also corrupted the endeavor by starting to use Valvoline's new cleaning oil. Restore maybe?

I cook with cast iron so have "seasoned' the cookware. The idea is somewhat the same. Heat up the metal, add oil and allow to cool down. A long-standing tradition.

I would like to think these new oils & additives do as advertised. I will be fine if they do not harm. My sentra has 25 years of 3,000 mile oil changes with full synthetic oils. No brand loyality for me but name brands. Almost always 5-w-30. Some 10-w-30.

To your question. I do not know that oil with greater viscosity "falls" away more than thinner oils. Wish i did know for sure.

 

[Gen 6 Mach1]

Again whether the high is 15* where I live or 115* where you live, the oil temps driving around normally will be within 10-15* at full operating temps. That doesn't warrant the change to w50 just for the temperature alone, maybe going up to w30 but certainly not to w50. Now if you're beating on it or racing constantly in that Arizona weather sure, going up in viscosity will help because the oil temps will be much higher.

FWIW, I personally use a 5w50 when road racing in the summer. I'm a firm believer in thicker oil for higher temps. But to putt around on the street you don't need anything more than a 5w30 even in Arizona.

Thank you for your input to this Thread , I am no oil specialist . My personal preference to run 5- 50w FS in the Summer Arizona Desert Heat doesn't cost any more per case that 5-30wFS as of 4-6-26 ,I hope in the future that doesn't change , you know .

I do spirit around , although the engine isn't under the loads of full out racing . But the under hood temperatures when I open the hood to let heat escape, feels like opening an oven door on broil. I think I'll purchase a infurred thermometer , I'm curious to the under hood temperatures.
Edit: I purchased the thermometer, my curiosity is worth the few bucks , and nice to have around the house.

 

[Mike Pfeifer]

I’m sure this could be tested. Get some of both types of oil, heat it up to operating temp and dip some parts in and let hang to see how it behaves. My guess is the difference is negligible.

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