low coolant level

[johnt-rox]

Anybody ever had their coolant get spit out after filling to about 3/4 gallon less than full? The motor runs fine after this and never really gets hot. When the truck was new it had an air tight seal. I could open the rad cap and get an air release after sitting for 4-5 days. I think it started when I killed it trying to go through a little water (about 3 feet deep) and the intake intook a big gulp of H2O. Bent a connecting rod ect.... That was at 90K, replaced the rod & piston and ever since had this coolant push out after filling. Lived with that for another 60K til that motor died and replaced it with a junkyard 4.0 with about 70K on it. This motor does the same thing. The radiator was replaced way back, pump has been changed as well. I had the heads off in both cases, could I have done something in putting the heads back on? TWICE? The thing that gets me is it seems like it don't want too much water. After it spits out what it don't want it goes fine for months. Any body out there?

 

[moto_head90]

Did you let the coolant system bleed itself when you put everything together. You have to run the engine at least till the thermostat opens and add coolant accordingly all while the cap is off. If the system is bled but still spits out coolant, then it sounds like you have a bad head gasket.

 

[johnt-rox]

Thanks for the reply.
I've put water in, topped off added you name it, in every way you can. This isn't something that just happened recently, I've had this for at least 4 years now and since I changed the engine this past fall and still have the same problem, I always fill the rad with the engine running and run and flush with the thermostat open. The more I put in, the more it spits out to a level it likes. It will act like an over heated motor on the first shutdown after getting to operating temp.(gurgeling, steaming over into the catch tank) and then it's done, all this with out a high temp reading. If I leave it at that level it won't boil over and I can drive till the next time I check fluids which could be a week or a month. I put up with it on the last motor cause I thought it may be a head gasket and 60k latter I change the engine to it doing the same thing. I guess I'm looking to hear someone say that happens on all old 4.0 motors. Any other takers?