Myth: Once you switch to synthetic oil, you must always use it

Chris from Commack Diagnostician Posted   Latest   Edited  
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Myth

I've heard this from customers and shop owners. For the life of me, I can't figure out where it comes from. Maybe it's a sales tactic, maybe it's a lack of knowledge, maybe it's both. I've heard and seen a synthetic oil switch "cause" a few oil leaks. I attribute that to the better quality oil washing the sludge away from the gasket sealing areas. There is no way, in my experience, that a vehicle that calls for a conventional oil, you can't switch back and forth. 

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Timothy from Brampton

 

Diagnostician
 

Interestingly enough my own personal vehicle has an interesting issue with non dealer synthetic oil. 2014 ecoboost f150. When ever aftermarket synthetic oil is used my rear main leaks. Complete stop with dealer oil. I would love to understand it. Many of my customers think that a synthetic oil change once per year is good for their car no matter what we tell them.

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Ronald from Trail

 

Technical Support Specialist
 

An aftermarket oil that is Ford approved for that engine?

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Chris from Commack

 

Diagnostician
 

Agreed. I am a stickler for oil. When I come across a new-to-me engine, I make sure it has all the requirement. I’ll even go so far as to call the company to make sure it meets all the requirements. It’s kind of a CYA policy as well. If anything goes wrong with the engine, I can’t be blamed for servicing it Incorrectly. 

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John from Beaver

 

Instructor
 

Yeah, there are aftermarket oils that easily meet the specs for that engine. You won't see "approved for" like the GM's dexos1 licensing requirement but when you understand the specs its very easy to choose the right products for Ford.

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Sean from Cornville

 

Owner
 

I just looked up a 2014 ecoboost on Mitchell, and it calls for MOTORCRAFT SAE 5W-30 Motor Oil or equivalent. That tells me that it's regular conventional 5w30. Does Ford call for something different, and Mitchell is stating the wrong info? This wouldn't be the first time I have seen wrong oil specifications published there.

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Rex from Sarasota

   

Owner
   

I have been told that Ford has changed oil recommendations for the Ecoboost engines from a blend to a full synthetic (Duh! Ask VW&Audi how well conventional oil works this turbos). So old spec's may be incorrect.

The 3.5 & 2.7's were calling for different oils at one point. Not sure now. After a lot of research, my oil distributor (who drives a 3.5 Ecoboost) recommended Pennzoil Platinum 5W30 product made from natural gas for my Edge Sport 2.7. No leaks as yet with a 5000 mile service interval.

Rex …

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John from Beaver

 

Instructor
 

Did Mitchell also show the Ford specification WSS M2C946A? That would be the 2.0l in a 2014 Edge and it is a 5W30. Meanwhile the 3.7l takes a 5W20 that meets Ford specification WSS M2C945A. Here is another question. How far will Ford's oil life monitors allow a vehicle to go between services?

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Sean from Cornville

 

Owner
 

I was looking up a 3.5l, because it was an F150 mentioned in the earlier post, and this is all Mitchell says: "MOTORCRAFT SAE 5W-30 Motor Oil or equivalent"

Apparently Mitchell is giving the wrong info again.

I have asked several times in the past about Mitchell's listed spec, just because I don't fully trust it.

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William from Surrey

 

Owner/Technician
 

Hi Chris. Totally agree that synthetic and conventional can both be used. I also agree that oil leaks are NOT caused by synthetic oil. As you said superior cleaning washes the sludge away and I also believe that because the Synthetic is a more viscosity stable oil it doesn't thicken like conventional oil and thus will leak out of small sealing imperfections that a thickened conventional oil will not. There are many oils both synthetic and conventional that meet the Ford specifications. When considering which to use I do not base my decision on cost. My main consideration is the type of engine. I recommend a synthetic oil for all Variable Cam Timing and Direct injection engines. I have had to replace camshafts, HP fuel pumps and camshaft actuators due to lack of proper lubrication. I say lack of proper lubrication not lack of maintenance which is another whole subject. I do several Ecoboost engines a year because of this. Last one was ; you guessed it, 2014 F150 Ecoboost 3.5. Complete timing and advance set up as per TSB for actuator rattle on startup.

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Chris from Commack

 

Diagnostician
 

I agree. Synthetic oil on anything with variable cam/valve timing should be a must. The parts that create the variable whats-a-doo-dads are usually dead ends in the oil path. Sludge is a big no-no here. As hot as a turbo runs, a good quality oil that won't cook under those conditions is important as well.

Another thing to consider is: all synthetic oils aren't the same. Just because your Mercedes says Mobil 1 under the hood doesn't mean you can go to Walmart and pick up any Mobil 1 5/30 they sell. The oil in Europe is different than the oil here. At the very least, get a Euro spec oil for a Euro vehicle. Get an Asian spec oil for an Asian vehicle etc...

I'm a big proponent of Liquimoly and Motul (being a euro guy) I've actually seen them clean sludge out of engines that lesser brand synthetics (Mobil 1) left. My BMW has 244k on the clock, and looks like a brand new engine under the oil cap.

I guess the point of this rant is to take the country of origin into account when choosing your oil. Someone a lot smarter than me did a lot of research on the right type of oil for that particular oil, This needs to be taken into account when at the parts store.

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