While rebuilding my 460 I mounted an oil temperature sensor near the drain plug on my pan. Under medium to high loads the oil temp. goes up to 240 degrees. I thought it may have been due to radiant heat from the left side exhaust pipe but a heat shield didn't make any difference. Should I add an oil cooler or is this within the proper range? I'll soon be making a trip with a 3,000# trailer behind the 11,000# motorhome.
There are only 600 miles on the fresh engine and I'm using a straight 30 weight with some AC Delco EOS (for extra zinc).
What d'ya guys think, the cooler the better?

 

Well if your gonna add a cooler for the engines lube system, maybe consider using a well made, low restriction, high efficiency, flat plate design, WITH a thermal bypass of the cooler, so you don't over cool the engines lube in the colder months.

Oil is designed to work & likes to be in the 190 deg F range.

Towing & running in a hot climate in stop & go traffic, with the AC on, will really put the heat to a crankcase lube & filter, so be sure to use a lube with a high volitility number & a filter that can take the heat.

Imo a well made synthetic lube might be a good option for this application, but check it's specifications & choose carefully, all synthetics aren't created equally!!!!

Opt for a good well made oil filter media too, one with a large media surface area, that filters well, but with low pressure drop & that can also take the heat, like Motorcraft, ect, ect.

 

I am a big believer in oil coolers.
When dino oils exceed 220 degrees, it can start stressing.
Remember too that the engine oil is used to cool the engine, as much as 50% depending on design.
Many, if not most, auto trans problems are due to overheating. A cooler is a must for an auto. jd

 

I think he's talking about engine oil, so I'm not sure why you bring up auto trannies.

In any case, even though 240F is a little high, I think it's still OK for engine oil, though I'd definitely use a multi-weight oil, and maybe synthetic, once the break-in period is over. Actually the higher temps could be partly due to the fresh engine

 

The higher temps are probably due to a fresh engine with good tight bearings. Also, oil is always going to run a little hotter than the coolant, since the oil doesn't have a radiator to shed excess heat.

Personally, I wouldn't like to see sustained oil temperatures below 212F. You have to remember, that the oil also has to boil off any moisture. Also, moisture is a combustion byproduct. Where is it going to go if it gets past the piston rings? That's right....

I think it's doing just fine the way it is. Most modern quality engine oils have a flash point of at least 400F anyway.

Also, aren't there additives in modern oil that only work at higher temperatures, like moly?

This is my theory anyway. Maybe I'm way off, so dont take it as gospel just yet!

 

All good info guys, thanks.
I have the same sensors mounted in the pan of the C6 trans., a US Gear overdrive, and the rear end with a rotary switch to select any of them to display on a single guage. The OD runs really hot so I have synthetic lube there. The C6 has the stock cooler in front of the rad and has always been the coolest of the bunch strangely enough.

 

My response was to engine oil. The subject was also oil coolers, so my comment relates to the subject. Transmission oil temps are most efficient from 170 to 190 degrees. These comments are for those reading the post that might have an interest, if no interest, disregard. jd

 

My point is that it is misleading to throw in something about tranny failures since hot oil is not normally the root, or the main cause of engine failures. And while radiator type engine oil coolers are available as add on items, and even OEM on a few selected models, they're on a comparatively few models vs. the pretty much universal ATF cooler.

 

You are running the oil temp in the normal range at 240F. You are near the top of the normal range but still normal. I would suggest an oil cooler because of the load regardless of the trailer. An oil cooler needs to have a thermostat to avoid over cooling the fluid. As stated, the oil is also a coolant but nowhere near 50%, more like 12-15% for most applications. When the oil passes 265, you are flirting with oxidation on a wholesale level regardless of dino or synthetic so consider that the max you want to run an oil and not for extended periods either. For your application, I would suggest Mobil One, Redline, or Royal Purple. For those that know me, I don't recommend a synthetic often. You need to stick with the above choices due to the type of basestock used and the resistance to thermal breakdown, oxidation, etc. The pick of the litter for me would be the Redline and change every 5000 miles. Other synthetics may not have the basestock to support the extra load/heat. I would also suggest a viscosity of 5w-30 and not a 15w-40. Thinner fluids capture and release heat faster and provide more cooling.
Most tranny fluids are a synthetic anyway( most are a Gp III) but even they won't stand up to the loads that you have without some concerns. Even though you have a cooler in front of the radiator, any movement much past the 200F range and I would be looking for an additional cooler with a thermostat/by-pass. Your transmission will love you for it not to mention your wallet.

 

Then I guess Flash's post mislead you too. He also brings up the subject of auto transmissions. My post is not misleading at all if one can read and comprehend. jd

 

If you consider that a consolation price, then be very happy with it.

I guess you really need that after posting that non-sense 50%...

Flash had some good technical details (though the "much past the 200F range" isn't very well defined) while you had very little of that with the exception of the vaguely defined "stress" over 220 degrees.

 

As usual, Flash is right on... take his advice.

As an aside, and hopefully not too confusing for those of you who mix up transmissions with engines , Harley-Davidson Twin Cams are designed to have their motor oil run at 230F, and that's dino oil. Just mentioning this as a point of comparison. On my bike, I installed a H-D oil cooler and the thermostat on that cooler is set at 180F. Since installing it my oil temp has never exceeded 200F. I'm not too concerned about this being too cool... even though it's below the boiling temp of water, it is still hot enough to expedite evaporation. I prefer to have the extra margin of safety for longevity's sake (both engine and oil).

Back to Fords, if your motor oil is routinely in the 230F-240F range, then I would definitely recommend a synthetic, and Red Line is probably the best choice, especially since polyol ester based oils (of which Red Line is one) can handle the highest heat and leave the fewest deposits as a result of that heat, and the deposits they do leave are softer and less destructive that those left by PAO based oils.

 

Cool, didn't think that I'd find a Harley post here. I've been pondering this since I got my 2005 RoadKing, as I'm in Phoenix and I'm sure that the engine/auto transmission oil just roasts in there!
See jimdandy how confused I am? Maybe someone needs to go back to the "See Dick Run" books.

 

The ideal operating range for engine oil is 180°F through 200°F. While operating within this range, the oil works as a lubricant, coolant, and cleansing agent in the engine. Modern engines generally run with radiator coolant temperatures between 200°F and 220°F with oil temperature ranges between 20°F and 75°F HOTTER. In other words, when the engine is performing flawlessly, the engine oil is already overheating! Oil that exceeds 220°F rapidly loses its ability to lubricate and cool causing accerlerated fatigue and premature component failure.

www.permacool.com

jd

 

Jim, so are you saying that modern engines have a design flaw the requires aftermarket products to fix?