The Stovebolt Site Forums The Shop Area Engine Shop anti-freeze in crankcase

Helping a friend with a 48 216 engine that he had rebuilt by a reputable machine shop 6 years ago and was only run then on a dyno. I'm putting the truck back together for him and started the engine up and after about 10 minutes the oil pressure started to go down to almost zero. I shut it down and drained the oil to find a lot of anti-freeze in the oil. I did fill the radiator the day before and ran the oil pump with a drill to get things lubed. Checked the oil dipstick before starting it and was normal. Can't figure out how the anti-freeze is getting to the crankcase. I pulled the oil pan off, filled the radiator back up with water and applied 5 psi to it and it's not losing pressure and no leakage in to the crankcase. Very confused. Any ideas. Thanks Dave

I only know of two mechanical ways coolant can get into the oil pan. 1. Blown head gasket. 2. Cracked block or head. 🛠

How much antifreeze is "a lot"- - - - -a quart, a gallon, or a few ounces? Was the oil milky-looking? Some 216's have a hard time maintaining any oil pressure at all at idle, particularly if they've been assembled with main bearing clearances a little on the wide side. Since the rod bearings aren't pressure-lubricated, they can be a little loose without dropping oil pressure. Not so with main and cam bearings! How much oil pressure did the engine have when cold and the pump being run by a drill motor?
Jerry

There is a very direct path on a 216 to let antifreeze into the crankcase. There is an oil line that goes from the oil distribution valve through the coolant passage in the block and out the other side under the side cover. Where the line exits the block under the side cover, the line is soldered to a fitting that is threaded into the block. If that solder joint isn't good or the line is cracked from trying to bend it into place, coolant will leak into the pan from under then side cover.

Good point! Since the oil pressure is much higher than the pressure in the radiator, if the cross-block line has a problem I would expect to also see oil in the cooling system.
Jerry

As much as it would suck if that through-the-block oil line is bad, it would represent the luckiest day of your life compared to other potential causes already listed.

I have recently done 2 repairs to 216 engines that involved fixing the oil feed line at the junction behind the push rod cover , surprising just how much coolant wept from a small crack in the fitting .

When I ran the oil pump with a drill, I had my neighbor watching the gauge in the truck. He said it climbed to more than half way on the gauge and I had oil coming out of the rockers so I assumed that all was good. Before starting the engine, I checked the oil and radiator levels and both were good. When I started the engine the oil pressure was 30 psi. By the time it reached 180 degrees it was down to about 5 psi. Pulled the oil drain plug and couldn't believe how much anti-freeze came out with the oil. At least 2-3 quarts. This system runs a 0 psi radiator cap. I pressurized the radiator to try to find the leak and it's holding pressure. Looking in the shop manual it talks about nozzle jets which direct water under pressure to cool the valve seats. Is it possible this pressurized coolant is somehow getting to the crankcase? Thanks for all of the input. Dave

My 1939 216 has 30 psi when starting cold. After it warms up it idles 5-10 psi and 15+ when driving. That's about normal for a 216. My engine runs great.

Reasons for anti-freeze in the oil

Cracked block
Cracked head
Cross over oil line leaking
Bad/wrong head gasket
Head not torqued down properly
Block/head surfaces not cleaned/machined properly

I had a Ford 1963 262 engine that had been rebuilt. While adjusting the valves with the engine running the oil turned milky. Retorqued the head. I drained the oil, replaced the oil filter and oil. Problem solved.

Rick

Thanks for the input Rick. Doesn't make sense that the radiator holds pressure when I pressurize it while not running. It appears to only leak in to crankcase while running. I will check and retorque head and start over with fresh oil and just water in radiator. Thanks Dave

Just to comment on the jets. When looking at the face of the head, those are little copper inserts in some of the coolant feed holes. They do little more than affect the flow pattern. Did you have any unusual noises? If that internal line isn't correctly located, it can be bumped by a pushrod.

Thanks for input Truckernix. No unusual noises. Today I'm going to re-torque head and adjust valves. Got to try something

Something to consider, and I have encountered it in the past, is that the leak is from a crack that opens up when the engine reaches full operating temperature. The metal expands when heated, and contracts when it cools and can "close" a crack to the point that it will only leak a minimal amount which could not be noticed by a quick pressure test. Have you tried getting the engine up to operating temp with the cap off and then doing a pressure test?

What you're describing makes sense. No I have not run it again. Still have the oil pan off. I'm a little bothered by a few things that I'm seeing with this rebuild. I might have the owner take it back to the shop that did the work. Thanks for your input Dave

Going back to the original rebuilding shop for a second bite at a possibly rotten apple might not be the world's best strategy. Very few people know how to rebuild Babbit-rod engines, particularly when it comes to scraping rod bearings for the correct fit and setting up oil clearance with shims. Aiming the spray nozzles for proper connecting rod lubrication above idle speed is also a vitally important procedure.
Jerry