Oil temp?

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orlando fl
I know this topic has been discussed but I don't think with this oil. I have a 2014 Focus ST. 1st OC was at 1k using MC 5w30 Synblend. 2nd was at 3k using the same oil. 3rd OC was at 6k using Formula Shell Full Synthetic from BJ's. My oil temp gauge always stayed at the middle hash mark of the gauge with the MC oil. Today I noticed that gauge was noticeably below(about a 16th" below) that mark after the oil was well at operating temp. (45 mins of city driving with 2 good 5.5k turbo pulls). Can a different oil make THAT much difference in operating temps?
 
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I've never noticed a difference in oil temps when using oils of the same grade. Going from a 20 grade to a 40 grade my oil temps were consistently 10f-15f cooler using the thicker oil when cruise was set on the highway.
 
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i would take ford's factory gauges with a grain of salt. on nearly all other models the gauges are glorified idiot lights and could be easily replaced as such. usually their temp gauges like that have 4 positions. "cold" "normal" "almost too hot" and "overheating" and nothing in between the first three. their oil pressure gauges are worse yet. they simply show "low" and "enough" nothing higher than half-way, and nothing in between "low" and "enough" maybe they've actually put a real gauge in the ST. the manual makes you think they did, but I'd want to verify that the gauge display isn't being filtered (dummy'd down)by the PCM before I took it too seriously. they are very well known for their dummy gauges. myself, on the one vehicle (94 ford escort 1.9L) I installed an oil temp gauge (just for fun) I never noticed any difference in oil temp based on oil selection. Motorcraft, Castrol syntec and mobil 1 all always showed the same temp for the type of driving I did. the oil temp on that vehicle always ran a tick over 190°F for normal driving. it would frequently get up to 230°F if driven at 75mph into a headwind, or in very hilly terrain where you were often going nearly wide-open in 5th gear to maintain speed. FWIW, anyway.
 
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tojo1968

Thread starter
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orlando fl
I am not sure how accurate the gauge is as far as reading the correct temp, but the temp is still noticeably lower with this oil vs MC.
 
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Virginia
Synthetic oil - Heat Reduction One of the major factors affecting engine life is component wear and/or failure, which is often the result of high temperature operation. The uniformly smooth molecular structure of synthetic oils gives them a much lower coefficient friction (they slip more easily over one another causing less friction) than petroleum oils. Less friction means less heat and heat is a major contributor to engine component wear and failure, synthetic oils significantly reduce these two detrimental effects. Since each molecule in a synthetic oil is of uniform size, each is equally likely to touch a component surface at any given time, thus moving a certain amount of heat into the oil stream and away from the component. This makes synthetic oils far superior heat transfer agents than conventional petroleum oils. I don't know if this is actually true - but here is the source: http://www.opieoils.co.uk/t-tech-is-synthetic-oil-better.aspx
 
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Burlington, Ontario, Canada
Originally Posted By: tojo1968
I know this topic has been discussed but I don't think with this oil. I have a 2014 Focus ST. 1st OC was at 1k using MC 5w30 Synblend. 2nd was at 3k using the same oil. 3rd OC was at 6k using Formula Shell Full Synthetic from BJ's. My oil temp gauge always stayed at the middle hash mark of the gauge with the MC oil. Today I noticed that gauge was noticeably below(about a 16th" below) that mark after the oil was well at operating temp. (45 mins of city driving with 2 good 5.5k turbo pulls). Can a different oil make THAT much difference in operating temps?
Since we're talking the same grade I doubt it's the oil but what's more likely is that now we're into the fall (yes even in Florida) the lower ambient temp's are lowering somewhat the maximum oil temp's you're seeing. It's unfortunate the OT gauge isn't calibrated so that we know how much change in oil temp' you're noticing. Another possible factor could be a lower coolant level so you might want to check that.
 
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