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New to car ownership, I was confused by this oil checking procedure in the 2022 Hyundai Tucson owners manual:

Turn the engine off, remove the oil filler cap and pull the dipstick out. Wait for 15 minutes for the oil to return to the oil pan. Wipe the dipstick clean and re-insert fully. Pull the dipstick out again and check the level.

It sounds like I should take out the dipstick and oil filler cap immediately after stopping the car, then leave them off for 15mins before checking. Isn't there a risk of dust etc getting into the oil? Any idea why the manual doesn't just say to wait 15 mins and then check the dipstick?

materialDefender
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1 Answers1

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I do not have a definite answer as to why they say to remove it, I see two possibilities:

  1. An abundance of caution: maybe with this or another type of engine there was a case where oil was pressurized and came out of the dipstick when it was removed. I've never heard of such a case but it's possible. The wheels blocked instruction does seem to indicate there's lawyers at work, as you say nobody does that
  2. Accuracy: it's possible removing the oil cap is required to allow the oil to pool properly for a correct reading on the dipstick, by leaving it on you may get under or over-reading

However, your question is asking whether you should follow the instructions, to which the answer is yes. While it's completely possible it's an unnecessary step put in by over-zealous legal specialists, it's more likely there's a very good reason behind it.

As for removing the cap completely, it's easy to miss a cap that's loose as opposed to one that's completely off, and you don't want to drive with a loose oil cap - best case you have a mess to clean up, worst case it's a seized engine.

GdD
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