Rebuilt my 350 about a year ago. But it hasn't hit the road yet due to a long resto. Just fired it up and moved it in and out of garage.

So after it sat all winter I noticed some foam on my oil filler cap this week. I'm thinking condensation from setting all winter.

So I drained the oil and it looked good, but I noticed some streaks of pure green antifreeze in the oil on the top of my drainpan after draining oil.

I changed oil and filter and pulled a valve cover and cleaned it up and put it back on. Fired up the engine and let it run about five minutes. Pulled the same valve cover and noticed pure green antifreeze in the oil puddled around where the headbolts are.

What should I do now?

get a radiator pressure checker, it's a little hand pump with a hose with a radiator cap gizmo on the end. sometimes the chain auto parts will rent or loan them. pull your cap, install the pump, pump it up to 15-18 lbs. pull both valve covers. the pressure gauge on the pump will probably be bleeding down, keep it pumped up while you carefully with good light inspect around all the head bolts to see if coolant is leaking around them. Did you use sealer on the head bolt threads? look at the lower row of short head bolts too. If you can't find it around the bolt heads the next likely place is the water ports at the 4 corners on the intake. check that the intake bolts are tight. If you don't find it keep it pressurized while you pull all eight spark plugs. crank the engine, see if you get water out of a cylinder. if it passes all this you're looking at tear-down. Let us know what you find.

FWIW anti-freeze in the oil will cause bearings to wear fast. I had an '88 Chevy truck with what turned out to be a cracked block. Lost coolant gradually and I noticed oil pressure gradually dropping. Finally tore down engine and discovered the cracked block. If the head bolts are leaking, my machine shop recommends Permatex #2 as a sealant on them and I've had good success with it.

You can drain the coolant, and remove and reseal in the proper tightening sequence each head bolt, and retorque to spec. Should be no big deal since it is a fresh engine.

Thanks guys a long day at work today has kept me from checking it out further.

I don't have a pressure tester and the local parts stores don't rent them. They are $100 for the cheapest I can find. I'm still working on finding one.

I used the Indian head shellac on the threads when I installed the bolts.

Thanks guys a long day at work today has kept me from checking it out further.

I don't have a pressure tester and the local parts stores don't rent them. They are $100 for the cheapest I can find. I'm still working on finding one.

I used the Indian head shellac on the threads when I installed the bolts.
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You can make one with an old radiator cap, Drill a hole in it & have someone hold a rubber tipped air gun in the hole & pull the trigger a few times,,
It will work better if the water level is lowered so you have room for air expansion.
Just don't go crazy with the pressure. ;)

Or you can take the upper & lower hoses off, plug one & pressurize the other with about 15lbs of air.

I thought about that. But I was wondering if I could install the cap and stick rubber tipped nozzle in the overflow stem?

I figured I would cut the regulator down to 15-20lbs at the compressor.

Also, could I pull the spark plugs and put air pressure in the cylinders? Then with the radiator cap look for bubbles to see if I have a blown head gasket or crack?

You want to be careful putting pressure on the system. The max you should ever go is 3 psi higher than the cap pressure. FWIW, $100 for a tester is well worth it. I test any cooling system repairs before reassembling the entire car, and can go back to fix leaks way faster. Not to mention, finding a leak on a hot engine means waiting for it to cool before fixing it. I've had my Snap-On set for about 12 years now, saved me a few times. ;)

I've never bought one of those things, often wished I had. Always worked somewhere where the shop owned one or something. I wonder if I could use a coolant recovery cap, hook up to the overflow nipple, use my leakdown tester. It's got a nice regulator.

I've never bought one of those things, often wished I had. Always worked somewhere where the shop owned one or something. I wonder if I could use a coolant recovery cap, hook up to the overflow nipple, use my leakdown tester. It's got a nice regulator.

Tom, if you do, you'll want to run a ball valve before the system pressure gauge, but after the regulator. Part of the process is letting it sit under pressure for 5 minutes with no leakage at the gauge. A 0-20 psi gauge is ideal, so you'll be able to see minute pressure drops. So the setup would be cap, hose, gauge tee, ball valve, then regulated air source.

I thought about that. But I was wondering if I could install the cap and stick rubber tipped nozzle in the overflow stem?

I figured I would cut the regulator down to 15-20lbs at the compressor.

Also, could I pull the spark plugs and put air pressure in the cylinders? Then with the radiator cap look for bubbles to see if I have a blown head gasket or crack?
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Pressure in the cylinders will only tell you if the cylinder is leaking & my experience has been if you are getting any appreciable amount of coolant in the oil it is not coming through the cylinders unless you have a crack in the bore.

15-20lbs would be just fine & yes you can use the overflow hose but again don't get stupid with pressure ;)
If you use the overflow hose you are blocking the pressure relief on the cap.
I think the safest route in lieu of the proper tool is to just pull the hoses, plug one, put a fitting in the other & stick 15lbs or so in the block & heads.

This also works great on a stand if you want to pressure check your block & heads when they are bare, even before spending money on machine work.
You need 4 plates to block the intake inlets & water pump inlets & of course core plugs in the block.
Then you drill one plate for a fitting & add air
Poor mans pressure check stand :D
With this you can put 50-60lbs in the cooling system & start looking for any issues,,

I've also heard about finding a rubber ball just a hair larger the the rad cap opening, drill a hole it it for an air pressure nozzle, stuff the ball in the opening, set your compressor at 15 psi and stick the nozzle in the ball.

I finally got in from work this evening early enough to do some checking.
I set the regulator on my compressor at 20psi and with a rubber tipped nozzle blew air in the raidiator overflow tube.

I checked a time or two and the cap was holding pressure on the system. So with one valve cover off I wiped down the head really good. Then I pressured the system and after 20-30 seconds antifreeze began to trickle from the headbolts. I still can't believe I'm this lucky. I'm just praying this is my problem. I know it is, I just can't believe I lucked out. Normally with me it's always the worst case scenario.

Anyway, what would you guys recommend using to seal the threads? The short external bolts that aren't under the valve cover aren't leaking. Should I pull those too?

Thanks.

pull them one at a time, clean them with whatever you need to get them clean and dry. Wipe a little RTV into the threads, mash it right into the valleys between the first 4 or 5 threads. re-install, forget about it. change the oil, change it again in 500 miles. after the first oil change take it on a pretty good road trip, hit the freeway, get the oil good and hot.

BTW, excellent DIY home testing on your part. You just saved yourself somewhere between hundreds and thousands of bux.

oops, the short bolts. if they're not leaking I wouldn't touch them. You gotr the one at a time part, right?

I plan on draining the radiator to get the coolant level down. Then one at a time remove the headbolts seal them and torque them back down.

I removed them one at a time today. Cleaned them really good and put #2 permatex sealer on the threads. Let it sit for 2-3 hrs and pressure checked before adding antifreeze. I can still hear a few hissing air around the heads.

Will these seal up or should I put some stopleak or something in there?

is Permatex #2 an RTV silicone stuff?

is Permatex #2 an RTV silicone stuff?

No, that's the old poop brown Form-a-gasket stuff. It semi-hardens, but is pliable. It should've sealed, but probably needed to cure with some heat first. It's hard to actually get anything into the threads themselves too, since most of it wants to stay at the top of the threaded hole when the bolts are run in. Might want to try to swab some onto the threads in the hole first with a small stick, before running the bolt in. That way, any pressure tries to push the sealant more into the threads, and it'll seal.

no it's not. wonder why you decided to use that stuff? that stuff is a left over form the olden days, AFAIC.

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pull them one at a time, clean them with whatever you need to get them clean and dry. Wipe a little RTV into the threads, mash it right into the valleys between the first 4 or 5 threads.

BTW, good luck getting that stuff off your bolts. Now it's in the threads in the block too.

What should I have used the blue or black RTV?

I used Indian head shellac the first time. That is what I have always used. When I removed the bolts it had none where the bolt threaded in the block it had all went to the top threads. Same thing with this permatex when I removed one of them that was still leaking. I don't think it's in the threads in the block or it would seal wouldn't it?

So I did a search and read that most people said Permatex #2. I've never had a head bolt leak like this before.