Just got a used Japan imported gp5, went for first free service which is required by importer for two year warranty.

After a lot of struggling to find an owners manual for the car I accepted my lot in life and settled for the Japanese version, couldn't find a matching Honda Jazz 2015 hybrid manual in English.

In that manual, with the help of Google Translate I read 0W20 is the accepted manufacturer oil. Striking up a conversation with the mechanic on what oil to use he seemed uneasy and said for our countries' warmer climate and busy urban roads it's preferred to use 5w30 instead which is what he ultimately put in.

Seems a bit questionable to me, some colleagues have mentioned that warmer climates like ours which can exceed 45C in heatwaves causes thin oil to be unable to have adequate pump pressure.

Any thoughts and opinions on the matter?

 

There's much more to oil viscosity than climate, while that is one factor, but there are seals and engine tolerances designed for a certain oil weight. Do not put 'thicker' oil or 'thinner' oil than what the manufacturer recommends. It's that simple. You can create a load of problems like blow-by, blown seals, stress the oil pump, decreased MPGs, and more.

Armchair engineers will tell you it's not a problem. While it may not be for their cars that are leaving a puddle in the driveway and have bigger issues than the oil they run.

Auto shops will tell you "it's the same" or "it's better for your car" when the reality is that 0W weight oils are almost always fully synthetic and cost more so they fill your car up with cheap non-synthetic or blended oils which are easily available in 10W-30, 5W-30, 5W-20, etc.

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That was my fear unfortunately. My understanding is the guys who built the damn thing know what goes in it better than anyone else. How serious is this issue? Should I get a couple of ramps, oil catch can and redo it myself asap or can it wait till next service? (likely next year) To my knowledge he did apply the oil filter correctly at least and swapped out the air filter which seemed almost brand new. That's probably gonna go back in some other poor sod's car that doesn't happen to sit by and watch what he's doing carefully.

 

Which raises the question, was the oil he put in conventional or synthetic 5w30?

 

​​​​​​He said full synthetic but could have put in anything really. He probably buys the oil by the barrel and then fills up the smaller containers to make it look like he's buying individual cans. I couldn't get a good look since covid nowadays allows them to simply put a barrier and keep us outside while they work on it. Saw what I could from outside the shop...

 

Agree with ikuto. Use factory recommended oil weight.

That said, this is not a crisis. Your car's not going to explode. But I would change it out, sooner rather than later.

 

Agreed and thanks everyone for the feedback. I'll work something out with my brother, he has a pit in his garage since previous owner was a mechanic and should be able to use that to get that job done right in the next couple of weeks.

 

Yeah, don't stress it. Just get it done much sooner than what the maintenance minder tells you. The maintenance minder oil change intervals are based off synthetic oil and high quality filters. Don't wanna be that guy that casts doubt and hates on auto mechanics, but our family used to run a full service auto repair here in Vegas, we used to run a special for Uber/Lyft drivers to get their oil changed with synthetic-blend, while we got a lot of customers showing up for the special, we lost money doing that promotion unless we managed to sell another service....we could break even if we lied and sent the customers home with non-synthetic bulk oil but that's not how we do business.

tl;dr; Let's just say we never really made money on oil changes and I can see why a shop would skimp their customers on oil changes.