here is the overall picture. about a month ago i bought a 96 F150 4x4 SC with a 5.0 Auto. it had several problems. most of witch i have repaired. one was a check eng. light for DPFE censer. i replaced the censer and the check eng light now cycles as it should. however about 2 days ago i noticed a white powdery substance around the larger hose where it connects to the DPFE. it appears to be antifreeze. is there any reason why it would be in there? how could antifreeze get into the DPFE? some of the other things i noticed where the water pump is leaking from the vent hole. i have a new one. it also is blowing antifreeze out the top of the overflow. once the overflow is empty it quits loosing antifreeze. i drive it about 80 - 100 miles a day. and have only added antifreeze to the overflow twice ( about 1 QT each time ) i recently installed a new temp censer and a new thermostat ( old one was broken ) and a new rad cap. truck is not showing any signs of overheating what so ever. it has good flow. also there is no issue of coolant coming from the exhaust. it has always run and drove just fine. it has a miner tick in the engine i thought was a wrist pin but it now looks like it may need a oil pump. will be addressing that soon. yesterday i gave the truck a tuneup. the former owner never did one. the old plugs wires and cap where original to the truck. date code on the wires 1995. truck has 196K. all the original plugs looked good with no sign of antifreeze on them. the longer i own the truck the more i find wrong. some examples are the former owner had the trans replaced and who ever did the work only installed 2 bolts in the drive shaft. part of the cross member is missing. the wiring for the trans was wrapped around the front drive shaft. i checked the fluid levels and found the front diff completely empty of fluid. i guess it's a good thing as the electric motor on the transfer case is not working. and the list grows. any thoughts about the DPFE would be greatly appreciated.

 

Somehow, your getting pressure buildup in the radiator.

Your best bet would be to do an exhaust test with a kit that can be bought. You don't have to have a busted head gasket, but if its not sealing well, it could allow for combustion gases to seep by and thus cause pressure in your coolant system. I know this happens. Been there, done that. So before tackling a water pump, do the exhaust gases in the coolant test so if it is that, you cana tackle all at once. Head gaskets, head bolts, and everything up.

Just my opinion....

 

Auto zone carries a block test tool for $25.00 and the fluid for $8.99 it looks like i will be spending a little bit of cash. thanks for the info.

 

well i did some research today. and i think i have ruled out a bad head gasket as the problem. the coolant leak only happens when the truck is being driven and it is an intermittent leak. i can only think of one place on the engine where coolant can come into close proximity with the exhaust and have an intermittent leak but not cause a spark issue or blow coolant out the exhaust. so if i am correct my coolant issue may be caused by my EGR cooler in the throttle body.