Oil in plug well

[Desert Rat]

Tried searching this on the forum but didn't see anything that addressed this in particular. . Getting some oil built up in the #1 plug well on my flathead. Just a little bit, nothing that is spilling off the head, yet enough to dab up with a rag. I haven't driven her much since I've noticed. I was going to do a compression check but thought I might damage my compression gauge if fluid got into it somehow. Maybe I'm overthinking this. Head gasket, bad valves, rings?? Hoping someone has seen this before and can shed some  light. 

37' Plymouth P4 coupe

Engine is 218" from a 53' 

single carb, mostly all stock 

[Jerry Roberts]

There is no oil up that way . Could it be anti-freeze ?

[Sam Buchanan]

9 minutes ago, Jerry Roberts said:

There is no oil up that way . Could it be anti-freeze ?

 

Agree. Probably some leakage from the thermostat housing.

[Sniper]

Since they smell, look and taste different it's be hard to confuse oil for coolant.  I have a similar issue at #4, no idea where it is coming from, maybe the oil bath air cleaner.

[JBNeal]

one of the advantages of operating a vintage buggy in a dusty environment is that eventually the dust clogs up any minor fluid leaks to allay any concerns about catastrophic mechanical failure...if'n the leak is big enough, then it never clogs, and then it's time for surgery

[Sam Buchanan]

2 hours ago, Sniper said:

Since they smell, look and taste different it's be hard to confuse oil for coolant.  I have a similar issue at #4, no idea where it is coming from, maybe the oil bath air cleaner.

 

I was seeing some random oil on the head, it went away after converting to a paper filter in the original filter housing. I don't know how oil was escaping the filter but it must happen occasionally.

[48ply1stcar]

I had the same thing after I had a engine rebuilt.  I looked every where for a leak, a oil trail nothing.  I attached my post from here the solution was not the solution.  I was at a car show at my  church and my rebuilder walked by.  I showed him the oil in my plug well.  He ah just put some "Stop Leak" in there.  That was four or five years ago the oil leak went away.  Until that time I was firmly against additives like that. 

 

 

[kencombs]

25 minutes ago, 48ply1stcar said:

I had the same thing after I had a engine rebuilt.  I looked every where for a leak, a oil trail nothing.  I attached my post from here the solution was not the solution.  I was at a car show at my  church and my rebuilder walked by.  I showed him the oil in my plug well.  He ah just put some "Stop Leak" in there.  That was four or five years ago the oil leak went away.  Until that time I was firmly against additives like that. 

 

 

 

Stop leak in the radiator to stop an oil leak?   How does that work?   Or was it not oil?

 

I'm guessing it was coolant leaking from a head bolt that did not have sealant on the threads.   Then the engine heat cooked away everything but the glycol.   Then it looks, smells and taste different than when it went into the radiator.   Am I close???

Edited March 1 by kencombs

[keithb7]

I had brown-ish sludge forming in my #1 sparkplug well.  Things started to slowly get a little worse. I’d clean it up. It would soon be back.  I believed it was burned coolant. I traced it to the thermostat water neck housing. I took it off. Looked at all the corrosion around the gasket area. I cleaned it all up. Put JB weld in the voids. Block sanded it smooth reinstalled all.  Test drive…Burnt coolant was soon back.  It could look like oil to the untrained eye. It is brown. 
 

Round two: I took the 251 ci cast iron head off. I spotted a crack in the head near the thermostat mount. It travelled down towards the spark plug.  Aha! I recycled the iron head. 

 

I installed a spare 228 ci 25” head that I had. It had a little smaller combustion chamber. A tad more oomph. She’s been all good ever since.  No more gooey mess. 

Edited March 1 by keithb7

[Desert Rat]

I have a paper air filter so I can rule out the oil bath. . Still convinced it is oil, just has the color and lubricant feel of oil. Although I did see what looked like possible weeping from the water pump elbow (which I did replace a water pump about six months ago).  Might try the radiator stop leak.. 

[DonaldSmith]

I had liquid around Plug No 1 and maybe #2. from time to time.  It seems it would come and go.  I found a sometime leak at the fitting between the radiator hose and the head. 

It was coolant, leaking at the bolt head and migrating to the plug well.  Permatex on the gasket and bolt solved it. 

 

Disclaimer:  This might not be what Desert Rat has, but I had to tell everyone about it anyway.         

[Sniper]

Simple resolution, put some UV dye in the radiator.  A UV light will tell us if it's coolant.

Edited March 2 by Sniper

[48ply1stcar]

On 3/1/2024 at 12:49 PM, kencombs said:

Stop leak in the radiator to stop an oil leak?   How does that work?   Or was it not oil?

 

I'm guessing it was coolant leaking from a head bolt that did not have sealant on the threads.   Then the engine heat cooked away everything but the glycol.   Then it looks, smells and taste different than when it went into the radiator.   Am I close???

You are probably right.  Thanks Ken.  I saw it after it ran for a while, so cooking it "Would"? make it thick and oily?

[Hickory]

I also had coolant leak into number one and a slight leak on the spark plug gasket so combustion gasses would turn it brown and black. I like snippers advice they make dye for oil and coolant to check for leaks. Could use water in radiator and see if the color changes or if it evaporates quickly.

[Dan Hiebert]

I have the same issue with my number 3 and 4 cylinders.  It is definitely oil, which doesn't pool, but there's enough to need sopping up.  I'm pretty sure it's a combination of blow-by past the rings and more so worn valve guides.  I've noticed on many L6's that there seems to be issues with valves and cylinders closer to the carb, I have theories why, but that would be a different conversation.  But - you can indeed have the same issues at all the cylinders. 

 

(Someone brought up an oil additive touted to stop smoking and blow-by a few months ago, perhaps that is the "stop leak" being referenced.)  

 

I had the coolant pooling in the #1 spark plug well as well.  The thermostat housing was the culprit, in part the same issue as kiethb7, which I fixed in the same manner (he had posted his resolution previously).  But it still leaked a little afterwards.  What I noticed is that I could not get a socket or box wrench over the left side bolt, had to use an open end wrench (which I did not appreciate, because I rounded off the bolt almost every time).  I took a grinder to the area on the housing adjacent to the bolt to the point I could get a socket over it, which allowed the housing to be moved to the left ever so slightly, which took it a tad further away from that radius from the top of the head into the spark plug well.  Absolutely no issue since.  Exactly why it worked I couldn't tell you, but it worked. 

[keithb7]

On 3/2/2024 at 12:37 PM, 48ply1stcar said:

You are probably right.  Thanks Ken.  I saw it after it ran for a while, so cooking it "Would"? make it thick and oily?

 

I suspect that whatever additives are in the coolant, glycol etc, when all moisture has boiled-off you are left with a brown gooey concentrate residue.

 

I struggle a bit to grasp how engine oil can get up into a sparkplug well. There is no oil above the valve covers in these engines. Except for the filer housing and oil pressure gauge line to the cab. Add to that the valves get misty oil floating around in the crankcase. Pressurized oil sprays up from the rod caps to the camshaft and tappets. It collects in the tappet oil pools. How does it get into a spark plug well?

[Los_Control]

The only way I can see oil getting there, is if the spark plug gasket is leaking?

Many years ago they used to sell the washer/gaskets over the counter ..... Today seems they are all machined fit and no more washers.

 

I can imagine if there was some blow by in that cylinder, it might be possible a small teeny tiny amount of oil is getting past the plug .... along with compression.

Then as you drive it, will add up to enough oil to dab up with a rag.

 

I certainly would suggest doing a compression check on the engine. See if that cylinder is lower then the rest and suggesting blow by.

 

I wonder if there is some place on the internet that can order those gaskets?

May not be the issue at all .... I wonder if you can clean it out then add a little water and run the engine. See if you can see little air bubbles coming out from escaping compression?

[kencombs]

6 hours ago, Los_Control said:

The only way I can see oil getting there, is if the spark plug gasket is leaking?

Many years ago they used to sell the washer/gaskets over the counter ..... Today seems they are all machined fit and no more washers.

 

I can imagine if there was some blow by in that cylinder, it might be possible a small teeny tiny amount of oil is getting past the plug .... along with compression.

Then as you drive it, will add up to enough oil to dab up with a rag.

 

I certainly would suggest doing a compression check on the engine. See if that cylinder is lower then the rest and suggesting blow by.

 

I wonder if there is some place on the internet that can order those gaskets?

May not be the issue at all .... I wonder if you can clean it out then add a little water and run the engine. See if you can see little air bubbles coming out from escaping compression?

Yep, they are available in a lot of places.   But, you can anneal the old ones to soften them and they'll seal better.

[Hickory]

I bet a new plug is cheaper than shipping new washers. Pull the plug and see what it looks like. Is the electrodes brown, black, white, wet. Start with that check the sealing surface. Replace the plug if its not sealing. That much fluid whether its oil or coolant, seams like would have a skip on that cylinder if it was coming from that combustion chamber. Being number 1 i still think its 75% a coolant leak from the water outlet leaking as it happens all the time. But it could be oil. Anything is possible.

[Desert Rat]

Its been a minute since my original post but I took a common sense approach and pulled the plug. Nice and tan. No signs of oil blow by from the rings and the engine has been running the same as the day I picked it up. So I can rule that out. Looked a little closer and it appears to be a very small leak at the bypass elbow. Many have speculated here that may be the case of the water being cooked out of the antifreeze leaving a oil-ish residue. Sure looked like oil but indeed was coolant. Thanks everyone.