Technical Foam under the oil filler cap of Ford 300 inline 6.

Looks like the crema from a good Americano under the breather/filler cap on the valve cover of my Ford 300 inline 6. When I pulled the dipstick I got the same thing up at the top of the tube. Is this a head gasket letting go? Aside from typical oil drips it doesn't show any coolant on the floor. Radiator doesn't seem to be down in volume.

 

Sure looks like head gasket failure to me.

 

Looks like condensation.

You will not know until you drain the oil. I have seen just that, and found clean oil below.

This was most often on engines that did NOT have a PCV system, or the system had failed.

 

Us gamblers have placed our bets, what's drained out of the pan is what we want to know.

 

What sort of use does the vehicle get??, short trips around town will do that..
Maybe the PCV system is clogged up as well, and not breathing as it should..
If that's the case, change the oil and filter and get it out on the hi-way for a decent run, and up to operating temperature for a while..

 

Def NOT a bad head gasket. I had a 240 in a F100 that did the same thing. It is condensation from short trips. You are not getting the oil hot enough to cook off the water in the oil. Take the long way home once a week and it will go away.

 

Hi All,
8-10 minutes to work is my trip. Propane vehicle. I just shook the filler/breather cap upside down and a bunch of clear water came out. No smell. Doesn't smell like coolant when I press my beak to the filler hole in the valve cover. Currently a road draft which I need to convert to PCV this winter once my insurance runs out in December. Fingers crossed this is a condensation thing. Never seen that one before. Thanks for the ideas. Will fire it up and take it for a rip then check again.

 

If it’s been the same low temperature there as it has here in Seattle, that’s typical condensation from short trips, cold engine, and no PCV. Even with PCV and propane, you could see that on such short distance trips with that cold Frazier river air over us. First time it happened to me was 1968 or so. A 30 minute round trip on the freeway (70 mph in those days) and it was gone.

 

It's definitely been cold hovering around -1 C/30 F. Everyone in the country laughs at us but, with our humidity that is damn cold. I'm chasing issues from a new build so I haven't got it over 50 mph yet. Tucking into the engine this winter.

 

I had a 63 ford with a later 390 in it years ago and the cap always looked just like that. Oil in the crankcase was fine, just moisture on the breather even on long trips. I ignored it and got many years of happiness

 

That breather looks like it could use a cleaning/replacing, what about the rest of the system?

 

The breather/filler cap is probably not drying out much between trips. Try removing the cap after those short trips and placing it somewhere indoors to dry out. Or alternatively, dry the cap with a heat gun before the next trip and see how much and how soon the condensation builds up.
That's not a cure but it is information, anyway.
Enjoy that new build. I hope you have it all sorted out soon.

 

sludge. needs to be driven

 

What thermostat is in it ? 300's need to run fairly hot. Standard T stat is 190 or 195 degrees. That helps some with the condensation.

 

I had a similar issue with a 289 that I built in the 60's to replace the 260 that the car came with. At the time it showed mainly on the dipstick and I had no clue. As I think back I had eliminated the PCV valve (a Weiand four barrel intake and Cobra Valve covers) and at least to me, explains the problem I had. No HAMB back then

 

I think what gimpy says is on track. That and maybe it just isn't driven long enough at temp.

 

Put a Stant Super Stat in that six, get one set for 195 degrees. Those sixes need to get hot.

Put a quart of Rislone in the oil run it for a few hundred miles and change it to 5 W-30 Mobil 1 synthetic. If you have a oil filter I like the Wix filters.

You should soak the road draft tube in gasoline or thinner.

 

That's and easy one. For these I have welded a threaded 1/4" NPT bung into a core plug that fits the hole where the road draft tube was. https://www.mcmaster.com/4513K71/

I cannot remember the core plug size, but it's easy enough to measure.

Into that goes a 1966-1967 Corvette 327 screw-in PCV valve. Part number is 33054.

Run a hose from that to a manifold vacuum port. If you need to, you can drill and tap one, but you will need to pull the manifold.

In you case, put a fresh breather on it, and change your oil.

 

I'll echo earlier advice. Add a PCV system, hottest thermostat you can find and drive it more. Not popular in the traditionalist world, but replacing the fan with either a clutch fan or electric with a proper thermostatic switch will aid in speed of warmup.

 

My cars always looked like that in the winter. Short trips, too much idling.

put in a 195 degree stat, and don’t idle it to warm it up. Get some highway running into your routine.

Make sure your crankcase vent is functional, install a new pvc valve, fresh oil, and a new filter.

With short trips like yours, and cold weather, 1500 mile oil changes aren’t unreasonable.

 

Years ago, whenever I would see that, I would ask-what kind of oil do you use? The answer was always "Pennzoil". Everytime! Maybe not anymore.

 

What brand of oil do you use?

 

Repeated use without getting to working temperature. Take it for a long run and it will be gone. A gallon of gas produces a gallon of water. So you get steam in any blowby. It can then condense on a cold valve cover.

 

Hi All, last I looked at the gauge while driving it was around high 180's and still climbing - short trip. When I crack into the engine this winter I'll put a 195 deg T Stat in it. Not sure on the oil. When I bought the truck I checked the oil (not bad) drove it for a few weeks then cut it all up. Wouldn't doubt Pennzoil as it seems that's the Service station juice of the day around my Hood. Propane vehicle so oil is really clean but, suspect very few miles on the oil change. Just got it back on the road a month ago and have only done short trips while I work out the bugs of a new build. Baldwin Filter. I took off the fan assembly yesterday to paint and between coats I idly cracked open the breather cap and here we are. I haven't driven the truck this week but, will today.

 

I’m with Gimpy, coolant temp might show 180, and that’s fine, but it’s oil temp that counts. It needs to be driven long enough and hard enough to raise oil temp above 212 degrees to boil off the condensation. Your short trip of 8-10 minutes will get coolant temp to 180, but it takes much longer to warm the oil temp to 180.

 

I'm sure the optimists are really hoping it isn't that head gasket. Me, one long drive will probably be enough to know for sure.

 

Agree! Lot of "milk" to be condensation. Sorry, betting something more severe. Mine was.

Ben

 

It dipped down into the teens the last couple nights here and I got my cardboard out for the front of the radiator so the engine can keep its heat. I was thinking about your six shooter. Maybe cover up the front of the radiator.

Do semi's still use those radiator jackets?

 

Than one still does not look like a head gasket to me, either.

The residue left behind is still the correct color for plain old oil.

Rust is not unusual with a condensation/PCV/short warm up situation.

Unless one drains out "the forbidden milkshake", it's not a head gasket.

 

It all depends on the specific design of the engine, and a fat-stack of other conditions, but complete combustion on the average happens with a coolant temperature right about 205ºF. I know that sounds high, but that's what it is.

Cooler is not better. It's worse, for the condensation reason and the combustion reason. The latter can wreck both performance and mileage (which are the same thing), and the former can wipe a bearing, leading to busted stuff.

I would put a 195ºF thermostat in it immediately. You need the oil to be there, or higher, as quickly as possible after startup.