We win some and we lose some.

[Schurkey]

By all means, re-seal the head bolt and hope for the best.

In my driveway, I'd be using Loctite 592. There are other PTFE-based, anaerobic sealers--Loctite 565, 567, and the "chapstick" semi-solid come to mind. There are also similar Permatex products. But Loctite 592 is the easiest to find locally, at least for me.

You will want the bolt and the hole to be CLEAN before re-sealing and torquing. Consider using the Loctite accelerator/activator.
www.amazon.com/gp/product/B0002KKTSG/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

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Worst-case is that the "bolt hole" is leaking because the head or block deck has cracked. Possible. Not enormously common.

I stopped a urine-stream coolant leak in an Oldsmobile 455 cylinder head (faulty weld repair) using K-W Permanent Metallic block sealer, according to directions (NO anti-freeze present, clear water plus sealer only) except that it took way longer than the 20-minutes stated on the product label. Note that the K-W product tends to settle, some of the "active ingredient" becomes a solid lump in the bottom of the can; and needs to be broken up. If I ever need to do this again, I'd buy a pawn-shop blender to chew-up the solidified product before use.

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[PlayingWithTBI]

Hell just throw a quart of Sodium Silicate in the radiator and run it! Years ago, on our road grader (International TD14A Engine IIRC) I sealed a blown head gasket with some I got at the local pharmacy. Made it through the season before I could rebuild it over the winter.

From Wikipedia:
"Sodium silicate can be used to fill gaps within the head gasket. Commonly used on aluminum alloy cylinder heads, which are sensitive to thermally induced surface deflection. This can be caused by many things including head-bolt stretching, deficient coolant delivery, high cylinder head pressure, overheating, etc.

"Liquid glass" (sodium silicate) is added to the system through the radiator, and allowed to circulate. Sodium silicate is suspended in the coolant until it reaches the cylinder head. At 100–105 °C (212-221 °F), sodium silicate loses water molecules to form a glass seal with a remelt temperature above 810 °C (1,490 °F).

A sodium silicate repair can last two years or longer. The repair occurs rapidly, and symptoms disappear instantly. This repair works only when the sodium silicate reaches its "conversion" temperature at 100–105 °C. Contamination of engine oil is a serious possibility in situations in which a coolant-to-oil leak is present. Sodium silicate (glass particulate) contamination of lubricants is detrimental to their function."

 

[L31MaxExpress]

I stuck a torque wrench on the bolt, was already tight, I backed off the bolt 3 full turns, ran it back down to torque spec of 70 ft/lbs and it stopped leaking. I will keep an eye on it but I ran it a solid 2 hours after washing the engine so that I would see fresh coolant. Fingers crossed so far so good. I have always used the white Permetex teflon thread sealer. To my knowledge this is the first SBC head bolt I have had leak. That stuff is like a paste that turns into almost a consistency of teflon tape. Apparantly backing it out and retightening it moved some of it around and allowed it to seal. The system held pressure the whole time it was running. Radiator hoses were rock hard. I also found a tiny seep at the coolant temps sensor in the driverside head. I snugged the sensor up and it stopped as well. Now if I can just get the bushings that thread into my auxiliary transmission cooler to stop seeping fluid it will be leak free. I don't want to jinx myself, but no oil leaks from this engine, no transmission leaks other than the aux cooler, no ac leaks, and no powersteering or hydroboost leaks. I have a small axle seal leak thats more of a seep on the rear passenger side to fix.

I also found my rigid plastic purge canister vacuum hose in the shop that had gone missing after the marine intake swap. I hooked the purge solenoid back up. The canister was so fuel logged that when the purge valve was commanded on the engine stumbled and ran rough with -25% short term fuel trims.

 

[L31MaxExpress]

The outside of the van including the under carriage is now as clean as I can make them. Engine compartment is near car show ready.

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[HotWheelsBurban]

Looks good! Those Vortec letters need some gold paint on them to match the van....

 

[Donald Mitchell]

Glad you got it stopped. It would be a shame to have to tear into it after you got it looking so good. I think that's the cleanest engine I ever saw in a van!

 

[L31MaxExpress]

Looks good! Those Vortec letters need some gold paint on them to match the van....

Except the Vortec box is leaving when I have time to finish my intake. Still need to cut down the sheet metal to clear the hood. I took a couple of sheet metal screws and attached it to the upper firewall in the wiper area for a few dyno pulls and it breathes alot better. With a paper filter in the factory 01-02 airbox shown, I am pulling down to 92 KPA on a 100-101KPA baro reading. With the massive K&N Duramax Kodiak filter it sits at about 97-98 KPA. The difference is over 20 hp. Just have to find time to custom fit it.

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[L31MaxExpress]

I have a 3.5" OD, 8" long piece of aluminum tubing that I slipped into the 3.5" filter opening leaving a couple of inches hanging out, then clamped the 4" silicone tube over the OD of the filter outlet. It works extremely well as a velocity stack, cramming more air in through that first bend. Converted it from a short ram to a mid ram intake lol. With a full 1 lb of dirt and dust in that filter, K&N shows it flows more than the K&N that fits the van housing does clean. Its also like a 4 ply filter for better filtration.

 

[GMCTRUCKS]

Check a fitting by the intake I think it’s a bypass hose or heater I vaguely remember some other guy had the same problem as you and did head work and it was the fitting now I’m not saying it’s not the head gasket I thought I would just let you know or share.
Good luck! X

 

[L31MaxExpress]

Check a fitting by the intake I think it’s a bypass hose or heater I vaguely remember some other guy had the same problem as you and did head work and it was the fitting now I’m not saying it’s not the head gasket I thought I would just let you know or share.
Good luck! X

Thanks for the tip. I got it resolved though. It was a head bolt seeping.