Hello,

My car is burning a significant amount of Oil, currently using mobil1 10w40. To the point that it is 1/4 after about 500 miles.

I took it to a mechanic who did a compression test, it passed with all cylinders at 175PSI. (I live in a high altitude)

He informed me that the cross hatch in my cylinder sleeves are “non existent”. He suspects a majority of oil is burning up in the combustion chamber and says the long term solution is an engine rebuild.

I don’t mind having to top off oil every few hundred miles. I would appreciate some insight on how this will affect the long term health of the engine. TIA

 

how are you driving the car? Ap1's burn most via the PCV system if driven very hard. So if you are tracking it, very aggressive driving, etc that can be part of it. Look up Rainh8r mod, valve cover baffle, etc. So that can be one culprit. Not as much if just normal street driving though.

Is it smoking at all? At startup, while driving, etc?

 

That's a 1/4 of the entire oil supply left (like more than three quarts of oil lost every 500 miles)?

Wow!

 

No smoking at all. I've not tracked it but I do take it through the mountains and canyons where I definitely get on it. I'll look into those thank you!

 

Yea. It's a bummer but I can handle that if it isn't going to cause long term damage to the car.

 

No smoking at all. I've not tracked it but I do take it through the mountains and canyons where I definitely get on it. I'll look into those thank you!

 

Wait, I thought you mean 1/4 between the low and high mark on the dipstick. If you have run it to 1/4 of the total oil left, you have already damaged the engine internals. That cant be right. If you were losing 3+ quarts of oil in 500 miles it would be smoking like a freight train or there would be an obvious puddle somewhere. Are you sure you dont mean it is about 3/4 quart low, aka it is still partway up the dipstick?

And honestly, while that is a little high on consumption (assuming 3/4 qt) the AP1 is a car you check the oil every fuel fillup. They use a bit normally. But typically not quite that much. But having to add 1/4 - 1/2 qt in 2 tanks (500 or so miles) is not super crazy either on some of these.

Mine sees the track more than the street anymore so I cant give a recent oil usage number on mine. In a 3 day track event I will maybe lose 1/4 qt since I did the baffle mod. But that is running it pretty hard at high rpm for 20 minute sessions. On the street I think I used to go through maybe 1/4 qt every tank or two of fuel.

 

What do the spark plugs look like?

Thanks!

 

i apologize for the miscommunication. I 1000% mean between the low and high mark of the dipstick. As mentioned before no smoke I’ve never let it get “empty” or even close to that

 

You cannot easily see the cross-hatch on FRM walls with a basic borescope. While the walls do wear smooth over 160k miles (causing some oil consumption), your great compression numbers mean a full engine rebuild is premature.

Before spending thousands on a rebuild, try these cheaper solutions:

​​​​​1. Change oil. Ditch Mobil 1. Get some high quality oil.

​​​​​​2. Replace the PCV valve.

3. Do the Rainh8r" Valve Cover Mod