1978 Ford F-250 still losing coolant

FRANK SKEA

MEMBER
1978 FORD F-250
V8
4WD
MANUAL
200,000 MILES

The engine is rebuilt with about 1000km on it then it sat for about 8yrs. Can't see anything in the oil or remaining coolant or white smoke or water on a piece of cardboard from tailpipe. Truck runs on propane. Water pump new, thermostat, rad, but still get bubbles in rad. Can it be intake gasket or maybe timing? What about from propane converse?(Condensor or vaporizer) Drained oil brought it back up to proper level and it hasn't raised ethier.
Please anything would be good.

1 Reply

RASMATAZ

MECHANIC
75,992 POSTS

Bubbles in the radiator-means something. Have the tests below done. Or try this retorque the heads.

Try bleeding it

BLEEDING COOLING SYSTEM
Always bleed air from cooling system after replacing coolant. Set heater for maximum heat. Remove radiator cap. Loosen drain plug and remove drain bolt (if equipped) from engine block. Drain coolant reservoir. Fill coolant reservoir to MAX mark with 50/50 water-coolant mixture. Loosen bleed bolt and fill radiator up to base of filler neck. Close bleed bolt when coolant flows out without bubbles. Tighten bleed bolt. With radiator cap removed, start and operate engine to normal operating temperature. Add coolant if necessary and check for leaks.

Have it block and pressure tested-do the block first to pinpoint a combustion leaking into the cooling system or a gas analyzer to sniff for hydrocarbons at the radiator fill neck.

Pressure test: do not do a pressure test if there's leakage at the headgasket this might cause coolant into the cylinders and lock it up or bend a connecting rod if cranked thereafter. The headgasket should be repaired before doing the pressure test.

If the block and pressure test passes check the following: Thermostat, Pressure test the Rad. Cap, Clogged radiator, Fan clutch, Radiator electrical fan, collaspe hoses, water pump.