05 ford focus - speeded up slow idle

[jorton]

5w-20 speeds up slow idle and improves idle vibration on my Focus. Had been using 5w30 and 10w30 for the past 9 months.

Now I understand how certain engines are designed for 20 wt oil. Will probably try super thin Havoline DS next oc.

 

[coffee]

My Volvos ran very nicely on MC 5w20 but I switched oils due to he fact that 5w20 was not recommended in my manuals and I did not want to risk anything.

 

[Curious Kid]

I do wonder - idle speed is monitored and adjusted by the engine control modual(s) and idle air valve. Perhaps something else is happening, coincidentally?

Interesting.

Coffee - for how long an OCI did you use a 20wt? What kind of ambient temp conditions and duty, and with how many miles on the engine(s)? Notice any thing different by way of engine/oil temps? Thanks.

 

[mdocod]

I think that was probably a coincidence.

A change in fuel used would be more likely to cause this change, but still very unlikely.

 

[Steve S]

Quote:

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I do wonder - idle speed is monitored and adjusted by the engine control modual(s) and idle air valve. Perhaps something else is happening, coincidentally?

Interesting.

Coffee - for how long an OCI did you use a 20wt? What kind of ambient temp conditions and duty, and with how many miles on the engine(s)? Notice any thing different by way of engine/oil temps? Thanks.

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