Well, I was just pouring in the new oil and realized I got 5w-30 instead of 10w-30. Can I leave it in there?
I don't think it would cause any harm in keeping it in there. Do a compromise & keep it in there another month & change it before the weather gets real warm.
Most of the newer cars call for 5W.
This is from the 98 manual:
-Steve "Those who hammer their guns into plows, will plow for those who do not." -Thomas Jefferson
'98 ZJ Laredo 5.2 Selec-Trac (249 to 242 swap)
'05 KJ Limited 3.7 Selec-Trac
'94 ZJ Limited 5.2 Q-Trac- sold, after 17 years
'67 International Harvester Scout 800; 345ci V8,T18 4spd, Dana 20 TC
'06 Chrysler 300C SRT8 6.1L
The 5W and 10W refer to the low temp (or "winter") viscosity. The difference is so small that your engine won't be able to tell the difference during late spring and summer. Both the oils you mentioned behave like 30W viscosity oils when the engine is warm and there is no difference then. Bottom line, don't worry about it.
__________________ Doug When all is said and done, more is said than done. Platinum '97 ZJ LTD, I6 (see profile) Paid for! Links:Kevin (AKA KOR) for ZJ & WJ stuff, Kolak for performance stuff. I6 performance info at Dino's jeep 4.0 performance site
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OME steering stabilizer, H4 headlight upgrade...