I just finished an engine swap of a 2.3 liter engine for a 2008 Ford Fusion. The engine that replaced the old one was rebuilt from the bottom up. New crank and rod bearings, new piston rings, new valve guide seals, new timing chain and gears, new water pump, new thermostat, new front and rear crankshaft seals, etc. A problem I have run into is first having the air purged out of the cooling system and filling it back up. This was done and now I have heat once again in the cabin. But, it had to be done twice due to an overheating problem after driving the car for about 5 minutes. The temp gauge would get pinned on Hot. So, the system was purged and filled back up again. Prior to doing the flush and fill the second time, the cylinder head temp sensor was checked for any damage or corrosion of which there wasn't any. But, after getting the cooling system to work properly so it provides heat in the cabin, it was found that when pulling the oil filler cap off while the engine is running that air was being blown out the oil filler hole. Also, when pulling the dip stick out while engine is running it also had air coming from the stick tube. Is this a normal symptom? Or is there a plugged or malfunctioning PCV or EGR valve? Also, can this condition cause air to be forced into the cooling system? I am also wondering if the new piston rings have not seated yet and causing the excess crankcase pressure. If anyone has experienced such conditions on a 2.3 liter 4 cylinder I would appreciate any input on what you may have found is causing such a problem. There is less than 20 miles on the engine as of this time.

 

What if you tried this,
Perform a compression test and see if more than one cyl is involved? I have found new rings have a problem seating when synthetic oil is first used After a period of time with reg oil then synthetic ,it does great !
PCV system should be able to handle what little blow-by gets out if working correctly.
EGR should not affect this.
The overheat if allowed to go far enough could burn valves or take out a head gasket or warp the head. Try to stay positive on this and try to avoid jumping to conclusions.

 

Did you figure out the Excess crankcase pressure problem? I have the same issue.

 

No, I am still having the same problem with excess crankcase pressure. The pressure cause the rear main seal to blow because there is so much pressure. Not exactly to thrilled that I will need to pull the engine in order to fix the blown rear main seal. It's a ton of work for a $15 part. I replaced the hose and the EGR valve hoping it would cure the problem. But, no success in that attempt to find the cure.

 

There is a spec for the ring gap when installing new rings, was this checked before assembly?