Hi guys, I drove the car to the dealer yesterday for a free compression test.

My engine was replaced few month ago, as is shown on carfax as short block replaced. The dealer told me I have around 4k miles on the new engine.

So this is the compression test result.

===========
remove spark plugs to test compression
cylinder #1 120, #2 119 #3 120 #4 120
===========

I would suppose they didn't do the test with engine pre-warmed(since I waited for 3hr for my turn). but It still looks like a new engine compression result. Considering it's not really a brand new engine (4k miles), do you guys think this result is reliable?

Another SERIOUS question, before I took off for the compression test, I checked the oil level and it's 1/3 inch from F. After the compression test, I've drove 150 miles, and then I checked oil level and.....It's 1/8 inch HIGHER than F!!! I would suppose the dealer over-filled some oil. I've heard a lot about the over-fill-up oil causes serious damage to the engine. I am very worried about my '8 now. And is there any way to drain some oil and let it falls to a normal level?

Thanks a lot

 

Compression results look great.


In regards to the oil level, did you check it right? Did you check right after the drive without letting the oil settle/wiping the dip stick?

 

Assuming you checked it right....as was already noted..........then 1/8th inch isn't going to hurt anything in my opinion. Not a recommended practice, but one or two times and it should be okay. YOu can drain some if you like, but I wouldn't worry about it.

A lot will argue with me but overfilling the oil can sometimes lead to some ending up in the airbox where it soaks the filter, might foul the MAF, can get into the throttle body, and over time gum it up.

Again, that's an extreme case, so don't read too much into what I wrote, just letting you know what can occur............not that it will.

Let the car sit overnight and then check it and see how much it's overfilled again and report back. Make sure you check it about three times in a row and wipe off the dipstick each time.

 

yes I drove to the dealer yesterday, and drove about 150 miles back home. haven't driven at all from then. I checked the oil today evening and it's still 1/8 inch above the F. so I don't know how much excess was it when I was driving home from dealer.

BTW I am in south texas, does the hellish weather make any difference in actual oil level?

 

Nah.

And I'll concur with Mazurfer... An 1/8" is no big deal. Like he (she?) said, nothing you want to make a habit of, but I wouldn't lose any sleep over it.

 

For the record................."He".

 

Duly noted.

 

The oil expands somewhat when heated, and will make a noticeable difference in the oil level indication. Mazda advises checking the oil when the engine is fully warmed-up. This will help avoid over-filling, as what looks full when the engine is cold will be over-full when hot.