Manager Forum

Have a 2010 Sentra 2.0 auto with about 40k on the clock. Came in running poor and complaint of oil blowing out dip stick tube. Compression tested 1-2-3 at 150 psi, 4 at 75. Looking into 4 with scope appeared to have hole in piston. Pressure tested cylinder and confirmed blowing thru crank case. Removed head, what I thought was a hole is a casting mark (DOH..slaps forehead). Got on the net and found a lot of these that have this problem. Nissan is turning down warranty for lack of maintenance records.
So I have checked the bores and none are worn and still show the original hone marks. Double checked with bore gauge..all in spec as to diameter and taper.
SOOO...my question is would you re-ring it or sell an engine. This is one of my used car guys. Good customer, don't holler about price to much. The car will be wholesaled, he just wants it right, at the least expense, before it goes to auction.
Thanks in advance. Jeff.

I would take the next step and pop the piston. If you're getting that much blow by then I think the piston will be junk. I would also look at the valves for that cylinder checking for carbon build up. Thinking along the financial end of the business you would probably make more and save your customer money by replacing the piston. I wouldn't touch the other cylinders, sometimes more is trouble. What really stinks is it's #4 and the upper pan housing needs to come off. If it was one or two you would have been able to pop them out. Head's already off so bite the bullet and pull the upper oil pan. I would charge them 65 for the piston, 490 for the overhaul set (more than you need but on jobs like this I hate getting hung up on a gasket I thought I wouldn't need, personal preference) and 2 hours diagnostic and 25 hours to replace the piston. Front cover needs to be removed to take secondary chain off. They claim the engine has to be out to remove upper pan, personally I don't know but with the head off and front cover needing to be removed how many bolts are really left? My basic thought is if this is a real big issue who's to say the used engine you install won't be junk like the original.

Customer came by last night. They want me to re-ring they engine. Checking identifix and the web seems this is a common problem. I did check..not a lot of rebuild data on this engine. Will keep ya'all posted.

Yikes. Hope all works well. Good luck

Take a good look at #4 piston. I'm thinking you'll find the rings in line or the piston battered and rings frozen. On a side note I would actually love to be able to go through an engine like this. Many years ago I had all the tools to do it. Valve grinders, mills, bores and all the machinist tools. Times changed and I sold or gave most of it away. It was more profitable time wise anyway to replace. Way to busy to rebuild an engine and turn a profit. Now that I'm backing away from the everyday grind I wouldn't mind setting up a little machine shop again and having a nice relaxing time.

I usually do leak down tests on low comp readings. Tells a lot about where the compression is going.

Yea that's how we did it. Had like 80% leakage. Been a while since we re-ringed an engine. kinda looking forward to it.

Update....engine has to come out!! Upper oil pan contains oil pump and balance shaft. Rods are not visible. Owner is debating the re-ring or replacement engine. Will let ya all know how it goes.

Replacing it with a used engine knowing these things are prone to issues, mmmmm, personally I would ring up a new piston, pop it in and call it a day. I knew the counter shaft needed to be dropped out with upper pan and discussed it when talking about the front cover needing to be removed. It's a toss up but I always lean to leaving them in.

UPDATE....Customer decided to pull car out. Asked me to put all the parts in the trunk and sent a flat bed. Paid the tear down and left. I didn't figure they would drop the money on it being it was a used car lot.

probably better off.