Ever had an oil related issue with STP, etc?

[KJA426]

I mean anything such as gumming up an engine, cold weather oil starvation or anything else with these thick additives.

 

[KJA426]

Also, has anyone ever run into a problem mixing these with synthetics?

 

[unDummy]

No and no.

But, wait for some hearsay stories from the 1960's.

 

[Oldmoparguy1]

I used STP oil additave since the 60's. Always used Chanpion plugs. Plugs always were shot by 8-10K miles. When leaded gas went away, I noticed that the plugs were lasting longer, but were still pretty much shot by 12K miles. About 2 years ago I stopped using it. Now the same plugs last up to 30K miles. I was quite suprised when I noticed this.