oil change: hot engine-cold oil??

[cephas]

Did oil change on daughters 2000 vw beetle. I ran it a few miles before draining. My oil stash is in an unheated area, and the temperatures have been on the cool side lately down into the low 30's at night. When adding the new cold oil the engine was definitely warm but not what I would call hot. When starting the engine after the change I noticed it was running as if it was misfiring. The check light came on, and later when checking the OBD scanner read misfires in all cylinders. The misfires only lasted a very short time but got me wondering about hot engines and cold oil changes. Think I'll try and get the new oil up to room temp. before changing next time. Any comments appreciated and have a good one.

 

[Triple_Se7en]

Maybe something in the way you jacked-up the front end of the vehicle caused that misfire with your fuel rail system?.... I dunno! Maybe a one-sided front tire raise that was high off the ground?.... again... I dunno. Could be a partially clogged fuel injector maybe.

 

[NYEngineer]

Wow. I've never seen that. Then again, I've never poured cold oil into a warm engine. I usually buy the oil right before I do the change, that way, the oil is as warm as the store.

 

[mechtech2]

Your sensors were warmed up, and the oil was thick enough that it caused more drag than should have been there with those sensor readings. Also, any variable cam system doesn't like thick oil.
I assume you didn't overfill it or spill anything.
If it starts and runs OK now, you should be fine.

 

[cephas]

Thanks for the replies. Used ramps so I don't think the fuel rails are an issue. I think mechtech2 hit the nail on the head. Starts and runs fine, got her back to school today. Interesting point about the cam system, I need to learn some more! As a side not VW specs call for 0 to 5w/40 oil in it. Also the sensors seem to be an issue on some of these. I'm afraid if I burp in it I'll set off the check engine light.
Have a good one!