chrisz71

so i recently rebuilt my 400, everything went well up until today. i pressure tested it yesterday, turned out good. held for 2 hours. started it, watched the radiator, good to go. so today im tuning the carb and setting the timing, checked out good. so i then decided to drive it to get some gas, and on my way back going up a hill i noticed it started spewing exhaust. so i got home, popped the radiator cap off and its now all yellow goldish color, like fresh oil. now when i pressure it, it drops significantly within like 5-10mins. ive retorqued the heads once.. how many times should they be retorqued? the blue felpro head gaskets.. cast iron heads, new arp bolts. would the bolts stretch that much that it would cause this, even after retorque?

Richardx2

Have you checked the intake for leaks, re-torqued the intake bolts?

Do you have water in the oil?

The head bolts should not stretch that much.
ARP sometimes have different specs than the manufacture:

Are ARP’s torque recommendations the same as the vehicle manufacturer’s specifications:


"Sometimes ARP will recommend using torque specifications that are different than the manufacturer, but not always. Our kits are engineered for specific applications, factoring in the necessary clamp load we’re trying to achieve, material type, block or head material, etc. To achieve our target clamp load, it may be necessary to use a different torque figure than what the factory calls out."

The Official ARP Web Site | FAQ

chrisz71

i have water in the oil but not much. someone told me it could be a crack behind the exhaust valve, since its running fine and not overheating. looks like there could be water in the oil but its hard to tell. not much if any, but theres a lot more oil in the water. i think most of the water goes out the exhaust... i know the block is ok because i had just gotten it back from the machine shop unless they just didnt catch something, but for some reason i doubt it

to answer your question, the head bolts were significantly loose after it had ran the first time with no problems, so i figured it was good to go for a test drive, and thats when it all happened. came home and retorqued them down, probably a good 1/4 turn, and i know i torqued them properly the first time. could the head gasket have been blown out by driving it before retorqueing?

one more question about your intake question.. could a crack or warped intake cause oil in the radiator?

Richardx2

Water in the oil makes the oil look like chocolate milk or coffee with cream.
With the head bolts that loose the head gasket could go either way.
Did the tail pipes look like they had steam/white smoke coming out? If so then you having a coolant lose that is exiting thru the pipe.

Yes a warped, cracked or intake gaskets not sealed good can cause water in the oil.
The intake does not have any oil galleys or passage ways going thru it so there is not a chance that the intake/gaskets are causing oil to get in the radiator.

chrisz71

thats what i figured. so, if the block were cracked within a cylinder wall, it would missfire. if the head gasket were bad, it would either missfire or have low compression, right? (all cylinders on both heads read between 145-150, hot and cold). would a crack in the intake port of the head put coolant into a cylinder? possibly hydrolock it?... mine fires up flawlessly, doesnt even act cold.. the exhaust is white when goosing the throttle, so its probably sucking coolant from the head into the exhaust and pushing oil into the coolant system in the process when the crack opens far enough? possibly? off with its heads i suppose.... also if i removed the schrader valve on my compression gauge, could i hook it up, crank the engine until it reaches max psi and see if it will drop? will that confirm my cylinder walls being ok/bad?

Richardx2

The intake gasket will leak water thru the intake ports into the combustion chamber, especially when the coolant system is pressurized. The same thing happens if the head gaskets are not sealed correctly, in addition there is the possibility that coolant will get into the oil.

A bad head gasket will cause the cylinder to have a low pressure and also will pressurize the coolant system rapidly if the leak is near a water jacket.

You will have to take the intake off before removing the heads and replacing an intake gasket is easier than pulling heads so if you going to disassemble remove the intake manifold as carefully as possible and do a thorough inspection of the gasket and the intake itself.

If you took good heads off a running engine then the possibility of them cracking while sitting are very slim.

Oil in the water could be from the fact that the block has some residual oil in it from the the machine shop.