Time at Operating Temp?

[blackdiamond]

Obviously, the reason short trips kill cars is because the engine oil never reaches operating temperature and as a result develops more contaminants. So is it possible to run a "long" trip to burn off the contaminants after a period of short trips? If so, how long would it have to be?

I'm thinking about driving 5 miles each way to work during the week and then a longer trip on the weekend.

 

[Gary Allan]

Some of the moisture and fuel maybe ..but the solids created by the enriched combustion process are going to remain ...or so I reason

 

[ericthepig]

My van has to be the poster car of short trips - elementary school is probably under 1 mile (muti-trips per day during school year to help teachers), grocery store 1 mile, church 5 miles, favorite resturants 2 miles, and I work at home. We do make a 1 hour one way trip probably once/6 wks (heavy travelling in summer though). I just did a dipstick UOA at 4.3k miles - the oil had been chged last Feb (did the UOA due to worry about fuel dilution - I didn't have any) - anyway, my numbers were good enough for Blackstone to say "go for 10k and resample". So anyway, you might want to do a UOA to see if things are as bad as you think.

You may already know this (assuming I'm correct), IMO I would also look for an oil with low visc. at 40degC instead of worrying about things at 100degC. Since your engine doesn't see much full op. temp., this will reduce wear in your situation.

 

[ericthepig]

edit above post - my wife's making most all these trips. I don't help elementary school teachers, though I'm glad my wife does.

 

[Merkava_4]

I never drive my vehicles unless I know I'll be able to get them up to a 180F water temperature minimum.

 

[Quattro Pete]

Quote:

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I never drive my vehicles unless I know I'll be able to get them up to a 180F water temperature minimum.

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But how does that help? The oil takes longer than coolant to reach that temp.

 

[ericthepig]

Since recently reading AEHAAS' articles, I'm seriously rethinking things with my van. Since 95% of it's school year driving is short trip to very short trip, I may be switching from my M1 EP 5w30 to M1 5w20. For an engine that sees very little time at full op. temp. the 30wt is kind've mute. 5w20 will have much better flow and thus relatively much better wear protection given the driving habits. Not sure if I'll leave it in there for the summer months that sees several thousand miles in trips.

Anybody see a problem here?

 

[Lonnie]

Try a cheaper oil and change it more often.

 

[spOILEDrotten]

eric, if you are indeed experiencing fuel dilution problems, you would have an oil that is getting thinner and thinner to begin with because gasoline is thinner than oil. Using EP 5w30 or GC 0w30 is probably the way to go. You wouldn't want your 5w20 to become a 0w10.

 

[Steve S]

Quote:

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Obviously, the reason short trips kill cars is because the engine oil never reaches operating temperature and as a result develops more contaminants. So is it possible to run a "long" trip to burn off the contaminants after a period of short trips? If so, how long would it have to be?

I'm thinking about driving 5 miles each way to work during the week and then a longer trip on the weekend.

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The main reason the greatest wear occurs at cold start up is the clearances are different, the pistons aren't round ,the rings aren't seating as well as when at operating temps the temperature activated additives in the oil aren't working as they should "not viscosity dependent" etc The engine will have the same cold start up wear all things equal on a 10 mile trip as a 100 mile trip. So don't worry about the cold start wear ,that is the operating duty of the vehicle.

 

[ericthepig]

Spoiledrotten - actually I thought I was having fuel dilution problems (from the dipstick smell) - but I sent it to Blackstone and wrote them a note on my concerns and they wrote back long-hand "no fuel in oil" (including the " close to 140k miles - travelling hard this summer) - if a 5w20 in a 140k toyota engine that calls for 5w30 is just craziness, let me know (given these driving habits).

 

[ericthepig]

Steve S - you bring up interesting pts on "cold start wear" - Haas was only looking at it from the motor oil side - not much discussion of engine dynamics that I remember. Will have to ponder this.