[MickyT]

406 with AFR 195 Eliminator aluminum heads. Drained oil today and definitely milky brown, last time changed with synthetic prob about 700 miles previous. Engine ran perfect no hesitation or rough running. Engine has about 6k on it and was all new rotating assembly etc. Has never overheated or had issues. So we removed intake and heads. All the headbolts at bottom of heads both sides were quite loose. The torque wrench was set at 65 and rest of head bolts were coming loose with the effort you would expect. Piston tops are totally clean, the carbon build up wipes off with a cloth leaving tops totally shiny - maybe evidence of water entry into cylinder and softening deposits under heat? Heads have normal buildup expected. Thinking maybe just head seepage from not being sealed tight. Wishful thinking or should I be looking somewhere else? Thanks in advance for any help

[Jess67]

I would change the head gaskets first if you cant find a another leak. But doesnt sound good... Aluminum heads need to be retorqued after a few hundred miles along with the intake... Need to clean all the bearing surfaces if the oil had water in it.

[Everett#2390]

Agree, change head gaskets, most likely since all the cylinders look the same, as I read your post. If you suspect heads, have them checked for peace of mind.
The right amount of water in the combustion chamber, as you say, does make steam and loosens up the carbon. An old school trick in cleaning comb chambers, rev engine up and slowly pour in water, a small pour, otherwise, engine dies, and carbon is removed.

Alum heads should be torqued in place, use soft sealant on the head bolt threads, bring engine up to temp, break-in camshaft, if needed, check for leaks, set hot lash, then let engine cool overnight. Next day, retorque. A week later, retorque.

You could get by with manually running oil pump with a primer and a couple qts of oil, doesn't matter what kind or grade, and clean the journals and remove some of the oil from the hyd lifters. After engine is together, change oil & filter after 200-300 miles, or maybe the second/third drive, since not driven much, and compare the results.

[Jess67]

Everett agreed with me... First time in almost 5 years!

[Eleanor's Nemesis]

I would recommend using gaskets made by Cometic when you re-assemble. They are not cheap but provide an excellent seal and can be reused. Give them a call and see what they recommend.

[MickyT]

thanks guys much appreciated. we didnt retorque didnt know we needed to.

[Steiner]

AFR also sends the heads with guideplates and rocker studs installed but not sealed. I know of this catching someone.

[Everett#2390]

Been 'bit' by other products also, thinking they were RTR, and weren't.

[Fred Ficarra]

Agree with loose head bolts. Another place not to overlook though is the intake gasket on either side of the distributor. Ask me how I know.

[DOUG G]

Using a MLS gasket ? Be sure to give both sides of gaskets 2 coats of copper spray letting it dry between coats as well as before install.

Also agree....loose bolts were the problem.

May even be able to pressure test the cooling system after reassembly (since heads are already removed)

Flush the motor with fresh oil as said above, and be sure to rotate it 90* a few times while spinning the pump.

[prostreet69camaro]

Did you put any liquid teflon on your head bolts. Some of them bolts are in the water jackets. I had Brodix Track 1 heads on my 406 and that was where the leak was coming from.

[MickyT]

k thx, think we will also replace bearings just to be absolutely safe, it was an all new rotating assembly so maybe cheap piece of mind.....

[Eleanor's Nemesis]

Originally Posted by MickyT

k thx, think we will also replace bearings just to be absolutely safe, it was an all new rotating assembly so maybe cheap piece of mind.....

FWIW, a long time ago I had a 400 with a cracked head....those notorious 441's to be specific-completely filled the crankcase with water. I noticed the oil pressure going to almost zero and water temp climbing out of control.

I drained the oil/water and filled the crankcase with kerosene 2 or 3 times after I put uncracked heads back on and then drained the kero.

Worked fine for me, I beat on that 400 like mad for a couple of years.

[novaderrik]

probably could have gotten by with just a retorque of the head bolts and a couple of oil changes..
unless it was making noises and/or there are sparklies in the oil, there should be no need to take it apart any farther than it already is. just get it together, heat cycle it a few times, retorque the bolts, and change the oil. wouldn't hurt to check the heads for flatness since you already took it apart.

[ssdoug]

Originally Posted by MickyT

406 with AFR 195 Eliminator aluminum heads. Drained oil today and definitely milky brown, last time changed with synthetic prob about 700 miles previous. Engine ran perfect no hesitation or rough running. Engine has about 6k on it and was all new rotating assembly etc. Has never overheated or had issues. So we removed intake and heads. All the headbolts at bottom of heads both sides were quite loose. The torque wrench was set at 65 and rest of head bolts were coming loose with the effort you would expect. Piston tops are totally clean, the carbon build up wipes off with a cloth leaving tops totally shiny - maybe evidence of water entry into cylinder and softening deposits under heat? Heads have normal buildup expected. Thinking maybe just head seepage from not being sealed tight. Wishful thinking or should I be looking somewhere else? Thanks in advance for any help

Tell me you did not use the torque wrench to loosen the bolts.