Switching to a higher viscocity oil after 100k?
 

Hello everyone. Civic Hybrid here with 100k. I'm currently getting around 42mpg, with 75% highway driving.

Few issues that I have noticed:

1. Rear wheels are extremely noisy. I had the rear control arms replaced with the newer ones, and the tires do have unever wear. I'd say the noise dropped from a 7/10 to a 5/10 after the new arms, but definitely still there. I'm thinking it could be from the unevenly worn tires..

2. Engine is NOISY. Had the valves adjusted about 3k ago. Always changed the oil at ~10% life, and used Honda Oil 0w-20. I'm thinking about switching to full synthetic Mobil 1, and maybe using a little thicker viscosity, say 5w-20. What do you guys think?

Re: Switching to a higher viscocity oil after 100k?
 

Yep, uneven tires cause an unbelievable amount of noise. In my case, after getting the rear control arms replaced, we also got new tires, and the difference was significant.

Sadly though the noise is back up to an extent even without perceivable uneven tire wear. Alignment seems fine (within the 'acceptable range'). Perhaps I need to balance the tires.

Using Mobil1 sounds like a fine idea - I myself use Mobil1 or Amsoil 0-20. But what prompts you to want thicker oil? Are you trying to deal with the noise, perhaps? Using thicker oil is known to lower MPG significantly, and I am not sure there is a good enough reason for you to sacrifice MPGs.

-ag

Re: Switching to a higher viscocity oil after 100k?
 

The reason I want to use a slightly thicker oil is because the valves are VERY noisy. I have a 94 Acura with 180k, and that engine runs much quieter than my Hybrid. Recently had the valves adjusted at Honda and no significant difference.

I've also heard people say that as the engine gets more miles (100k+) then it's a good idea to switch to a little thicker oil?

Re: Switching to a higher viscocity oil after 100k?
 

Hi,
The only thing you can do for the tire noise after you replace your worn tires is rotate them religiously at 7000 to 10,000 miles. Make sure they are inflated evenly and to a pressure at or near cold maximum.

As for the valve noise. Your valve train is just inherantly noisy due to its variable valve timing and the ability actually shut down cylinders to reduce pumping loads and losses. Mine was noisy from day one. We have 135,000 miles on Mobil 1 0-20wt. I do not plan to change. Oil changes every 10,000 miles. I adjusted the valves at 100,000 miles expecting to reduce the noise. It was no help. Just drive it!