replace air compressor on cummins big cam 350

Make sure this is open toward the rad.It you cant find the compression leak if any there is some more test i can tell you before you do any more parts replacing.Also that engine is to run anywere from 200 to 205 degrees on the coolant.It will have a 190 or 195 main termostatfor the coolant.It should idle all day at 190 degrees on coolant.The oil temp will run around 240 or higher.Also there is a time or two i have seen the after pluged from guys using stop leak.Stop leak should never be used in a BB4 rad. So on a BC4 there is a bleeder tube standing up with a hose to the top of the rad or tank which ever it has and a check valve in it. All engine get some compression into the coolant but cant be much. Also there is some trucks that have a air control heater control inline in the heater hose that can pass air into the coolant. If you have some you have a head gasket leaking or injector tube leaking compression into the coolant or a air compressor passing air into the coolant. After the engine has warmed up like i told you there should be no bubbles in the bottle. A new engine will pass bubbles into the bottle untill the engine temps have came up. Watch for air bubbles in the bottle after the fan has come afew times and the engine temps have sabablized to operating temp. Run engine untill it warms up at maybe half throdle and run it some more untill the fan come on at less 3 times. Dont matter if rad cap is good or bad but take a clear bottle and put some clear water in it and drop the over flow hose from the top of rad down in bottle.

then the next thing is to give it a bottle test on the rad. That will tell you if some one used the wrong seals or not as well as telling you the condition of the water pump and if the belts are slipping. The reason you cant put it in the water manifold is you will have restrictors in the gaskets for the manifold seal. At 1800 the water pump pressure should be around 38 to 40 psi with or with rad cap on.

First i will ask what kind of fan clutch does it have? The next thing is to put a low pressure gauge of 50psi on the side of the block into the coolant and not in the water manifold. This engine is a hard engine to troubleshoot for heating. Anybody good on Cummins Big Cam iv low flo overheating problems? This is what has been done so far This is a Cummins BC 4 400 lo flow Recon engine with about 30,000 miles so far we have replace radiator with a 4 row dimpled tube core, water pump, both themostats and the POS is still getting hot any help will be appreciated .Tony

Replace air compressor on cummins big cam 350