Oil found in the intake manifold and cold air intake system!

Maintenance/Repairs
1

I have a 77 bronco with a 5.0 efi engine from a 97 Ford Explorer. I noticed there is oil in the cold air intake area and upper intake manifold. I was checking on things and noticed oil around the PCV valve and on the outside of the cold air intake system. Should I be concerned about this? I have done some research. I checked the PCV valve and intake manifold gasket which appear to look fine. The PCV valve rattles and the gasket is intact. Granted there isn’t a lot of oil when I looked inside the upper intake manifold but thought I should write and ask if this is a problem or not. Should I just replace them pcv valve any ways and recheck it after driving it for a few miles? The explorer did have 110K on it but when we took it apart we thought the engine looked great for how many miles it had on it. We did change out the cam and timing chain but as far as the other parts, we did not replace.

I am also getting a unusual reading to not reading with my oil gauge. When driving for a about 30 minutes or so, My oil gauge goes down to zero when I’m stopped but when I’m drive off then the pressure comes back up. When I have it in park the gauge reads fine. Any ideas why this is happening?

2

Unless the oil is contaminated with fuel or long over due for a change the engine would be indicating that it is well worn.

3

I’d put a mechanical oil pressure gauge on it, see if the oil pressure drop is real. If it is, you have a worn engine, and the oil is from blowby. What is the compression?

4

If you have lots of blow-by due to a worn engine you will end up with oil in the air cleaner as it travels up the PCV system.

5

Are you burning a lot of oil? If not, pull your PCV valve out of the valve cover with the engine running and check for vacuum with your finger over the end of the PCV valve. If you don’t feel vacuum on the end of the PCV valve, then pull it out of the hose going to the intake manifold and check for vacuum on the hose. If no vacuum there, the port to the manifold is plugged.

6

PCV systems need a pretty high flow rate. It’s not just the valve. check to be sure the manifold vacuum fitting the PVC hose connects to is not plugged up, and the hose itself is in good condition. If you remove the valve from the hose with the engine running, the engine should stall because of the vacuum leak. If it does not stall, the system is plugged up…

7

If it’s not a PCV problem then the next alternative will be disheartening; a worn engine as mentioned.

Given the oil in the intake tract and the oil pressure gauge I’d probably be a bit pessimistic at this point.