Oil Viscosity for older engine


So on my '95 Galant the oil consumption is creeping to the higher range. It depends on the viscosity of oil put in. If I use 5W30 it burns 1qt/1KM, if I put 10W30 it burns 2qts/3KM. Now I live in South California and per the manual I won’t need the 5W30 for the most part. My question is;

Is there any benefit using the higher viscosity and burning less, like to the cat converter; not considering my pocket for the extra quart. I am concerned that the higher viscosity might be hard on the cold starts.

Also, when I go for the smog check should I have the higher viscosity oil to reduce the emissions. I am thinking more burnt oil will give out more hydrocarbons? Am I off on these.


I think the oil type would depend on the type of driving you do. If it’s the 2-10 mile variety then I don’t see a problem with 10W40, especially with cooler weather coming on.
Longer driving, 20-50 miles, etc., might let you get away with 20W50.

That’s going to be hard to say about hydrocarbons on a CA smog test, but a heavier oil should help. Swing by a local church before testing and ask for a little additional help… :slight_smile:


I like Okie’s answer (especially the last part about yet another miracle car product). Go with 10W-40. The heavier 20W-50 may also work but I only recommend it for those older cars with a few oil drips.


It seems your engine is reaching the end of its life. For Southern California a 20W50 would be OK, the small additional wear encountered at startup won’t shorten its life by much. In most warm countries 20W50 is the normal oil recommended. Whether it will pass the government exhaust test, for particulates especially, is doubtful, but you can try. The heavier oil will also reduce blow-by, which tends to force oil into air cleaner when the PVC system gets overloaded.


1 qt every 1000 miles is not that bad. I would just run it with the recommended oil. If you fail the smog test I doubt it will be due to the oil consumption. The cat can handle the small amount you are burning.

I’ve had vehicles that burn 1qt every 300 miles, and the cat handled it pretty well:)