Engine and Transmission Tech

All the aluminum radiators available now, most with integral trans coolers. If your running a stick, why not cool your engine oil ?
Cheers, Art.

Hmm...

I'll take a devil's advocate position to stir the pot.

There are many places where modernization is worthwhile - such as fuel injection - but engine oil coolers of any kind are an outdated idea for normally aspirated engines.

Reason 1: today's synthetic oils make them unnecessary. What makes you think good synthetic oil would benefit from running cooler? Oil needs to get hot enough to extract water that enters the crankcase as vapor and then condenses.

Reason 2: simpler is better. Consider the cost and complexity of plumbing between engine and radiator. Consider all the failure modes associated with fittings, connections, hoses, and pipes. What about the vulnerability of those components when things go wrong, such as collision damage? What looks more inelegant and cluttered than a hot rod with more plumbing than necessary? Plumbing gets in the way when servicing other things.

Much of what you mention, Curtis, also applies to automatic transmissions on millions of cars. Not that big of an issue.

Too cool engine oil is a big issue, though. Would certainly require the use of an oil cooler bypass thermostat.

Curtis,
Every car I have had for the last 15 years has had an oil to water heat exchanger, and not all of them were turbo. Yes they do add some complexity but why are the car manufactures doing this if not needed? I believe one reason could be faster oil warmup and oil temp consistency. Not that I had one, but even the Dodge caravan used a plate type oil cooler.

[www.amazon.ca]

Curtis, have any specifics ? Does everyone use full synthetics ? What is their maximum safe temp ? ? Isn't oil the second best coolant for the engine ? How big of an oil line are you envisioning ? Perhaps a small bypass of 1/8-1/4" would suffice ?
I have heard of track-day/ road race oils at over 300F. Fine for synthetics ?
Onward, Art.

Mobil 1's website says "Mobil 1 advanced synthetic motor oil provides outstanding high-temperature performance and is proven to protect at engine temperatures up to 500 degrees Fahrenheit." ref: [www.mobil.com]

I remember Bill Guzman speaking about carburetor tuning at a BritishV8 meet years ago. He made the point that running rich is one way to cool an engine right down. (Like, for example, if your radiator and fans aren't doing their job and you're struggling to get home without overheating...) But you wouldn't leave an engine mistuned like that, right? You'd fix the cooling system. And that's basically my argument here. If the radiator and coolant are doing their job, an oil cooler shouldn't be necessary and isn't desirable. (Turbochargers excepted.)

Do you consider Mobil 1 to truly be a fully synthetic motor oil?

Since Mobil 1 lost the Castrol lawsuit. Many synthetic motor oil contain Group III base stock. IMO, the original definition of synthetic motor using only Group IV & V should have been retained.

Science marches on, as the Group III base apparently is quite improved.

Most motor oil companies has stopped providing real information on their products.

Either way, Mobil 1 infers their product is stable to 500F. I don't know how or where they'd measure that. The video on the page I linked to above compares the film left on turbo bearings by other oils, versus the lack of film when their product is used.

Oil marketing has always been screwy. The companies want you to think theirs is better, but they also want you to think oil needs to be changed more frequently than it probably does. Some of the smarter long haul trucking fleets are changing oil at 75,000 mile intervals. Their engines are running turbos and relatively high compression too. Those fleets use oil analysis, so they know viscosity is holding up. On the other hand, consider the boutique racing oils. If racers stopped changing oil every weekend, those companies (Amsoil, Redline, Motul, Royal Purple, whatever) would sell a whole lot less oil. They'd be out of business.

"Some of the smarter long haul trucking fleets are changing oil at 75,000 mile intervals"

Do they add some oil additives periodically? I would think that would require much better filtration, as well.

" Big Fleets vs LBC's" is like comparing pumpkins to potatoes. Very little to compare. Great sales pitch, Mobile 1, but in the real
world, this ignores oil as a coolant. It removes heat from areas that regular coolant can't reach. What were the wear/longevity
results of that engine with near 500F oil ? All metals loose strength at elevated temperatures. Consider aluminum at 500F ?
As long as oil get hot enough to boil-off condensation, why would you run it hotter ? Do we remember the original post ?
Art.

I guess if the sump/pan is shrouded by underbody components, a cooler would be desirable.
In conjunction with a temp gauge so you can see what is going on.
Once you see, can decide whether a stat is needed.

In fact, a gauge would seem the logical starting point before doing anything at all.

Trans fluid life is dependent on temp, so they tell us. Both my autos have coolers.



Edited 1 time(s). Last edit at 03/17/2025 05:10AM by 88v8.