Moisture in Oil

jeeplvr247 · Post by **jeeplvr247** » Thu Jun 28, 2012 8:52 am

I am getting a yellow buildup on my dipstick from moisture in the oil. I think the head gasket is ok because there are no exhaust bubbles or oil in the coolant. My vent hoses are not hooked up properly which I think may be adding to the problem. I have a Carter YF carb instead of the YS, will I be able to properly hook up all the vent hoses with this carb. I am also missing the bit in the air intake tube that the vent hose connects to. What do I need to get the proper ventilation going?

Post by **wesk** » Thu Jun 28, 2012 5:40 pm

Even with the crankcase ventilation system connected properly you will still occasionally get the foamy moisture buildup in the dipstick area. The moisture is a common issue and when the jeep is a daily driver and is usually always driven for at least 30 minutes then the moisture gets cooked out of the oil system and the foam doesn't build up. It's nothing to get excited about. Just avoid short run periods when the humidity is high.

Also it's easier to answer a specific configuration question when you tell us what model jeep you have. That's why you'll note most of us list our jeep model we own in our profile signature.

jeeplvr247 · Post by **jeeplvr247** » Thu Jun 28, 2012 9:19 pm

My jeep is a 1952 M38a1. I am glad to hear that it is not a major problem. Is it even necessary to have the vent hose run from the oil filler to the air intake or is it ok to leave it hanging out the bottom of the jeep?

Post by **wesk** » Thu Jun 28, 2012 10:18 pm

For the crankcase ventilation system to work properly the air being sucked in to the crankcase was suppose to be filtered air. If you can't find a way to connect the dipstick tube vent hose to the air filter then just adapt a small filter directly to it.

In this example I did a conversion for a friend who had an M38A1 and a Civvy F134. He wanted the two mated together and a 12 volt jeep. I installed the civvy F134 and used a 60 amp Ford alternator/regulator system. He wanted the battery on the firewall so I dropped the oil bath air cleaner and installed an aftermarket small air filter on the carb and a very small air filter on the crankcase breather hose and clamped the filter to the firewall.

jeeplvr247 · Post by **jeeplvr247** » Fri Jun 29, 2012 1:13 pm

Ok, I have a photo album now so I will get some pictures up of my situation here.

So the one vent hose runs from the PCV to the oil filler and the red hose is running from the other side of the oil filler to the bottom of the jeep. If I get the piece for the air intake tube with the hose hook up on it and run that hose to it, will that achieve the proper ventilation. On the TM's it looks like the vent hose hooks into the air intake after the air filter, was there an additional filter in the intake tube?

Post by **wesk** » Fri Jun 29, 2012 5:54 pm

The early F134's had only one small 1/2" nipple on the filler pipe. That is what you see in my photo. Your F134 is a later engine with two 1/2" nipples on the oil filler pipe. In both cases the only purpose of the nipples is to allow fresh filtered air from the original oil bath air filter into the crankcase. You need to follow my photo above and add a inlet filter to your 1/2" hose and connect that hose to the rear 1/2" nipple on the oil filler tube. Then put the 90 Deg plastic nipple and rubber grommet in the top valve cover and run a short piece of 1/2" hose between the front nipple on the oil filler pipe to the 90 deg nipple.

The PCV valve and it's associated plumbing are completely independent of those inlet nipples. The PCV valve mounts on the side valve cover and is connected by plumbing to the intake manifold. It's sole purpose is to suck the vapors from the crankcase into the intake and to the cylinders to burn the crankcase vapors. That small steel tube runs from the PCV valve on the side valve cover to a threaded port in the intake manifold just below the carb.

So you should have NO hoses or tubes hanging free at the bottom of the engine.

The item marked manifold vacuum "T" is where the metal tube from the PCV valve is to be connected.

jeeplvr247 · Post by **jeeplvr247** » Fri Jun 29, 2012 7:14 pm

Thanks, I think I may be able to get it figured out now. Here is a better picture of the side of the engine. I am not sure what an inlet filter is. I am getting some venting out of the red hose and from what you are saying it sounds like that is flowing in the wrong direction. I am away from the jeeo for the weekend but I will start playing around with it when I get home.

Post by **wesk** » Fri Jun 29, 2012 7:51 pm

The little white pleated paper filter in my first photo is the inlet filter. You just insert it into the lower end of your red hose and clamp the filter up high on the firewall just like the one in my photo.

jeeplvr247 · Post by **jeeplvr247** » Fri Jun 29, 2012 8:35 pm

Oh ok. I think I am going to try to rig something up so I can run a vent hose up to the intake. Eventually I would like to get it back to stock but for now it just needs to work. Thanks for the help.

Post by **wesk** » Sat Jun 30, 2012 7:31 am

The only way to connect a vent hose to the intake on that jeep is to use the correct size plumbing and the PCV valve. The PCV valve limits the vented crankcase vapor flow to a very slow feed. This is what is called an allowable calibrated induction system leak. The greater additional air flow you feed to the intake manifold the leaner your fuel mixture will get and it won't take much to start burning valves.

So if you connect that 1/2" diameter vent tube hose directly to your intake you will end up burning up valves and rebuilding your engine.

jeeplvr247 · Post by **jeeplvr247** » Mon Jul 02, 2012 6:53 pm

I think something else must be off with my venting because from what you said it sounds like the red hose on my jeep should be sucking air in but is letting out some vapors. Is there something that could be causing the flow to go the wrong way?

Post by **wesk** » Mon Jul 02, 2012 11:11 pm

The PCV valve that belongs in the side valve cover on the driver's side of the engine does the sucking. No PCV valve, then no sucking and your red hose will simply relieve any crankcase pressure that builds up from the piston travel and blowby.

Passenger side of engine.
Item R is not a PCV valve. It is only a plain elbow.
I assume you are missing D?
Hose P is your red hose. It is the end that normally connected to the crossover pipe D that you should put a small paper air filter in and support it with a clamp on your firewall.

Driver's side of engine and the PCV valve plumbing.
Early M38A1's and those later units that had the fording system re-installed in the field will have assemblies L and S.
Late M38A1's without the field installed fording system will only have S and L will have been replaced with a plain tube.
You must have assembly S installed to provide the sucking needed to flush crankcase fumes and vapors into the intake manifold.

jeeplvr247 · Post by **jeeplvr247** » Tue Jul 03, 2012 1:53 pm

And the plot thickens... I have more messed up connections than I thought. I do have a line running off the PCV but it hooks into the "in" spot for the oil line (my jeep does not have an oil filter installed yet). I can only imagine that this is not the ideal arrangement.

Post by **wesk** » Thu Jul 05, 2012 12:24 am

That's not the PCV valve. That is the adapter (item E) on the side valve cover that connects to the PCV valve. When the oil filter was removed both the fitting in the timing cover and the 1/8"P fitting in the block behind the fuel pump were capped off.

jeeplvr247 · Post by **jeeplvr247** » Fri Jul 06, 2012 1:13 pm

Ok I think I may understand it now but I will lay out my plan before I buy anything. SO if I buy pretty much everything that is in that second picture of yours then I can just hook it up and run the oil line from part T to the oil filter? Are there any other lines that need to be hooked up?