Topic: Honda Civic Oil

[Keith_moon]

When reading through the owners manual of my car..2004 Civic...it appears that 5 W 20 engine oil is used. I've heard that 5W20 provides great start up ability in really cold weather, but doesn't offer the same protection of a 5W30 oil..I'm going to be Mobil 1 synthetic..Can anyone clarify??..Can I switch to 5W30??

[articsteve]

I am in same boat as you are.  Honda and Acura have this bug up their ass about 5W20 oils.  No one at Honda will give you a straight answer.  Honda tech support won't talk straight about it.

I heard that they use 5/20 over 5/30 because 5/20 will result in slightly better fuel mileage, at least theoretically, so they can claim better fuel mileage.  Some say the clearances are so tight that 30 weight is too thick.

However, I've read numerous times that when using a muligrade conventional oil the further the spread in the numbers the least effective it is.  For example,
a 10W40 is a no no. 10W30 has the maximum spread between viscosities before unacceptable compromises take effect.  Apparently, in temps above freezing, SAE 30 contains more protection ingredients than 10W30 because the chemists don't need to blend as many temperatures additives for the SAE30.

In my winter Saab I use 5W50 100% syn.  Crappy Tire brand, which is Shell.  Shell is probably the largest distributor of lubricants worldwide. Huge in the shipping and marine industry.  Mobil 1 too expensive for me.  I use their 15W50 in Porsche only.  I use 5W50 syn in Bimmer as well.  These are all high mileage engines though.

So, I will convert to Motomaster 100% syn 5W20 next change on the 2002 SIR.  I wouldn't mind using the 5W30 (spread between numbers on 100% syn does not matter), but I don't want any problems with warranty with Honda if son decides to blow this motor up as well.

 

[multipath]

Which leads me to a question that strays a little from the original question, but still to do with oil viscosity...

My '02 Mazda Protege owners manual states that 10W30 is the preferred weight of oil, and that 5W30 is acceptable.  I always use dino oil (worked with no problem for me for years, so I see no reason to shell out the bucks for synthetic), and currently, I use 10W30 in the warmer months, and 5W30 colder.  Am I wise to continue this practice?  Should I pick one weight over the other always?

[mrthompson]

I run 'thinner' oil in the winter (5W30) and 'thicker' oil in summer (10W40).  The 5W30 helps with cold starts, and the 10W40 holds up better to heat.  Keep in mind, my vehicle has 243k on it.  I've done this with all previous vehicles.  No probs so far after 10 years of this practice.

[lsmeteor]

For what it's worth, I used 20W50 oil in my Scirocco 16V, and I haven't noticed any degradation in the fuel consumption. It started well in the summer but it needed more time to fire up when the weather started to be cold. That is when I switched back to 5W20.