Car overheard when it wants to , even with fans on full. New oem items, thermostat,radiator cap,water pump. After market items hoses misimoto rad and fans. Fan relay mod. 50 50 mix. Vacume filled. New belts. Muti layer head gasket with arp headstuds and retouqed. Compresion checks out fine. The antifreeze gets Brown is and I'm getting a Brown sediment that is very thick in the bottom of the over flow bottle, also metal filings on the radiator drain plug. I was thinking it has a stop leak of sorts that refuses to flush out . Some one mentioned a faulty ofh. Is their way to check ofh for this kind of failure. Oh and the oil is clean and full .

I would replace the radiator.

+1 on the radiator, sounds like maybe some stop leak was n it at one time, its near impossible to get it all out

Did you fully flush the old antifreeze out the engine and cleaned out the overflow bottle before you installed all those parts. How the tension on you water pump? Over tightening can cause the pump to crack seal causing internal wheel to grind against the housing.

Radiator is new I bought it from a vender. If the belt was over tight then it still didn't explain the sludge. I drained the coolant and put in a prestone coolant system cleaner with water then drove it for 50 miles then drained that out Then used the prestone flush kit and hooked it up to a hose and ran the motor with the drain out till clear and cleaned out the over flow bottle. Car Will still over heat,heater blows Luke warm and still getting sludge in the overflow bottle.[DOUBLEPOST=1415948360][/DOUBLEPOST]After the flush .The next day I drove to work.which is about 10 min drive to the hwy then a 20 min drive on the hwy. Durring that time in link temps were in 196 to 206 range but as soon as I got off the hwy at a stop light and Sat temps shoot up 220 and climbed up to to 240 by the time I reached work in another 10 min ., and the sludge back in recovery tank. The commute back home wasn't as nice , because it overheated on the hwy heading back home. The heater is still blowing Luke warm unless it's at 240.

Sounds to me like you have 2 problems. Only way metal filings can get in the radiator is from the water pump. With the heater only blowing luke warm means coolant isn't getting into the heater core or the mixture control isn't opening up. Check the cable to it.

Best way to flush is a reverse flush. Run the hose into the lower radiator hose, remove the thermostat, seal it back up and keep flushing until all the crap is out of it. Good luck.

You have something inside your coolant system. It does sound like someone used a copper based stop-leak product in this car at some time (Yay)...

I would replace the heater core and remove the radiator to flush it out as THOROUGHLY as possible with some sort of radiator flush solution.

I would then reverse flush the block separately, in a similar manner, as this is most likely where the majority of your sludge is stuck.

There are other, more potentially dangerous chemicals you could use to do this, but I am not going to get into that, as it is an old mechanics trick that if not done properly, could cause serious bodily harm.