| Re: Start-up oil burn; should I go heavier visc? |
Subject: Re: Start-up oil burn; should I go heavier visc? by CentralCoaster on 2015/5/28 0:22:40 The cold viscosity rating is at 32F. So it doesn't mean squat except for that first 30 seconds of run time. Also keep in mind that all oils thin out as they heat up, some just more than others. An oil that maintained same viscosity after warmup would have to be rated a 10W700 or something ridiculous. I would expect thinner oil to always smoke more on startup. I don't think there's much harm in running a thicker cold weight. Don't hit WOT in the first 30 seconds and you don't have to worry about bearings. I run 15W40. Also, I've noticed the cat burns oil hot enough that you can't see it. So an engine could burn oil when warm, but not show it with the cat installed. I did valve seals on mine, but it still smokes when warmed up after idling a few minutes, such as at a slow drivethru. I've read that this is because the combustion chambers cool off and don't burn the oil completely. This is without a cat installed. |
