What is wrong with my dipstick?

Question

Please read my story and tell me what is wrong with my dipstick.

Recently, I had a problem with checking my oil level. The story begins about 7 months ago when I drained engine oil and poured fresh oil into the engine. The manual says oil capacity of my car is 4.25 Liters. I usually let the oil drain for about an hour and then tighten oil drain plug and pour about 4.2L of fresh oil. I have done this for several times and it has been quite successful because I always see the oil level on the MAX mark on the dipstick.

However, this time, an annoying problem happened. After changing the oil, I drove my car and checked the oil level the day after that. I noticed the oil level is a little below Max mark (despite pouring 4.2L of oil!!). I added about 100 cc of oil to compensate for it. I drove my car again and checked the level and it was still below Max mark! I added another 100 cc to bring it up to the Max mark. I drove it again and checked the oil and to my surprise it was still below Max mark!!!!! I decided to add another 100 cc of oil and then finally I could reach the Max mark! So, I poured 4.2L of oil + 3 x 100 to make it FULL. 4.2 + 0.3 = 4.5L (this is 250 cc more than what the manual says!)

I checked the oil later and it was full!! I was happy that the problem was finally solved and drove the car for a few weeks. One day, I checked the oil level and guess what I saw?! It was ABOVE the Max mark! I was so angry that I didn't know what to do! I sucked the excessive oil with a narrow hose and a syringe!

Now, my question is that why the dipstick didn't show the correct oil level at the beginning and made me to add oil more than enough and end up with an overfilled engine? Why did it take about 2 months for the dipstick to show me the correct level? I don't understand!

Answer 1

Not knowing exactly how you are checking your oil, there could be several things going on here:

• When checking your oil, your car needs to be on level ground. If leaning forward or to the rear, it won't read correctly. Doing this consistently will give you consistent results.
• In most vehicles, you need to allow the oil to drain back to the pan after you've run it. Some of the oil gets caught up in the heads and other spaces in the top of the engine. Giving it a few minutes will usually be enough to allow this to happen.
• Not sure what vehicle you're talking about ... if your vehicle has a vertical oil filter which attaches to the bottom of the engine, you should put oil in it before you affix the filter, that way your engine is not "run dry" (little to no lubrication) for less time at startup. This also takes up some of the oil after startup, so could be where part of it has gone.
• Typical way to check your dipstick should be: pull; wipe; stick; pull; check. This can affect where the oil sits on the dipstick. Again consistency is key here.
• One other thing: Your dipstick might not have been seated correctly at first.

The other thing which could have been a contributing factor here is if your initial amount of oil wasn't exactly correct, it could have set up things so it wasn't accurate at first, then if you are checking your oil after the fact (after oil was added), if you weren't accurate in how you are checking your oil, the problem may have exacerbated itself.

There should be a range of two marks on your dipstick which shows high and low. As long as you are between those two marks, you should be golden. You were right to remove the excess you found as this isn't good for your engine (there are several reasons, but won't go into them here). If you had put in the amount you are talking about (4.2L), you should have been within the marks. .05L is not a big difference.