Hi Everybody. I am new to the Forum. This is my first post and i am just looking for a second opinion on some trouble shooting I've done. I'll keep it as short as I can. I just bought a 2003 Neon SXT. The previous owner had installed a new head and timing belt and said it ran good but was throwing codes for a bad cam sensor so he had disconnected it. The car quit running after he had driven it for awhile like that and wouldn't start again. I did an initial compression test which revealed low compression (40 pounds average). I thought maybe something had gone wrong with the timing. Once i pulled it apart the timing was all lining up and the belt still looking brand new. I proceeded to a leak down test which revealed 30% leakage in 3 cylinders and 10% in another. The leakage is felt and heard through the oil fill tube. I concluded the lack of the cam sensor had created a cylinder wash condition so i added two caps of motor oil to the cylinders, turned it over for about 10 seconds and conducted another compression test. Results were 70-30-70-80. I then added a bit of engine restore to each cylinder and now the compression is average of 150. I know the car will most likely start now if if i put it all back together but I'm convinced that the rings and or cylinders are damaged. I don't have faith that the engine restore will last for any length of time so i'm thinking time for a rebuild or new motor. I haven't removed the head yet to look at it but just checking to see if i going down the right rabbit hole? Any advice would be much appreciated.

Thanks!

 

Welcome to the 2nd Gen Neon forum.
We don't know how many miles are on this puppy, nor how they were put on, nor what kind of maintenance its had.
If you can come by a fiber optic probe, or camera, you could remove a spark plug & have a look-see down the bore at the cylinder walls for scoring & maybe gather some insight into whats going on.
If nothing is apparent from that inspection & assuming its had reasonable maintenance & not too abusive use, I wonder if the ring lands might be varnished or clogged up with carbon, causing the rings to stick & not seal well?
If you think this might be the case, you could run the engine a little to warm it up some & try a piston soak with Marvel Oil, or a home brew of 50:50 mix of acetone & a quality tranny fluid like ATF+-4. Put 3-4 table spoons in each cylinder, screw the plugs back in a couple of turns to keep foreign material out & let it soak at least overnight. Then remove all of the spark plugs & crank the engine over to remove any excess remaining in the cylinders, before trying the compression check again.
Some thoughts for pondering, let us know how it goes.

 

Thanks for the reply Paw Paw and all good points. I have seen the compression recover with the engine restore so I'm pretty sure there isn't major damage in there but this was more of a test than a permanent solution. The car is closing in the 200k mark so I'm thinking i am going to go ahead and remove the cylinder head and inspect it. If it looks good, I'll probably pull the motor and see if I can just get it freshened up and re-ring and bearing it. At least that way I know it will last for awhile. Thanks Again!

 

Ok, sounds like a plan, will be interesting to hear what you find, so keep us posted.

 

I had a warped exhaust valve (burnt valve) on number 2, sounds like you may have the same problem. I did everything you did above, too. Does it look like a new head what's the model number? If so is it still under warranty, it should be for a year? I noticed at Advance Auto they only replaced some valves on my replacement head, so not sure how good a job was done, also I emailed the company that rebuilt the head, no answer. I didn't see any assembly lube on it either. I hear the other problem is a lot of transmissions going bad on Neon's, not sure if it's because of not doing a oil and filter changes. Not sure if your trying to decide if it's worth keeping the car?
I think you have the plug were oil gets inside when the cam sensor leaks oil. I found a spray for electronics to clean the connector let dry then added dielectric grease to the end of the plug. It's the third time I had to replace that part in ten years. The big o ring I think is what goes bad. Just my 2 cents on everything.

 

Thanks for replying Mike. Honestly I have been so busy I haven't had a chance to pull it apart. That's my goal for the upcoming weekend. That said, I think Paw Paw was on to something with the stuck rings. If it washed with fuel it would have lost it's lubrication. The rings would have really heated up. The oil looks clean and free from shavings so more than likely nothing catastrophic. After doing the leakdown test, I'm pretty sure it's not a valve. The compression loss was consistent in every cylinder. Good information on the Cam Sensor. This is most likely all because of that little part. Thanks Again!

 

So mystery seems to have been uncovered. This was a weird one. I finally got around to pulling the head and surprise! the Cam pin is broken off and based on the black rubber burnt all over the timing belt tensioner I'm pretty sure the cam pulley spun meaning when the timing marks lined up it wasn't really in time. Ugh! anyway. The cylinders look good. No scratches or ring ridge at all. I think i might just hone it, re-ring and bearing it. Have the head fixed and hopefully have a good running little 2.0. You guys think it's worth it? i found a complete motor with 120k on it. 205 to 215 compression for $650.00 Thoughts?