Odd happenings

[Nitrofueled14]

I've got two quick questions that hopefully someone can help me with. First one, I've got a 78 F-250 with the 351M in it. Sometimes, not all the time, when I shut it off after it's up to temp the coolant will bubble really loudly in the water pump. It will even do it when it's running. At idle you can hear it and actually feel it, especially when it's not running. I know there's probably air in the coolant, but I've tried getting out and it still does it. It's done it since the day I've had the truck. The temp never goes over 195, it has never had an over heating problem at all, especially with my electric fan, but it bubbles really loudly, and very hard to where you can feel it in the truck. Is that normal, or has anybody else had that same problem? Is there something I can do it about, or should I just not worry about it since it's not overheating at all. It just really bothers me when it's running when you can hear it because the water pump should be circulating the coolant so you should'nt be able to hear it, but I can so I don't know whats up with that.

My second question is after I drive my truck so it's obviously up to temp, if I shut it off and listen for a while, it will sound like someone is in the truck pressing and holding the gas pedal to the floor. I can hear gas squirting into the carb. It's got a Holley 4 barrel, and I know when they are hot it can make fuel bubble into the carb, but I didn't know it sounded like that. Today I could hear it squirting for a couple seconds before it stopped. I don't always listen to my truck after I shut it off, but I would assume it's been doing that every time I shut it off after it's up to temp, but I know excess fuel into the engine is bad for it, like when they run rich and it can wash down the cylinder walls, and eat up the oil. But I've never heard it like this, like someone holding down the throttle. When it's running it's only got 7 p.s.i fuel pressure, which should be alright for this truck so I don't know if it's just holding pressure until after I shut it off, then eventually releases it or something? Any advice, or anything maybe I could mess around with would be appreciated.

[loveshackle]

Both are pretty common, but rarely noticed, or loud enough to be noticed.

The coolant clacking issue can usually be attributed to trapped air in the system in the neighborhood of the pump / thermostat. Accentuated dramatically by a worn water pump, but I had a 351M that I never got to stop doing it, even though it was much quieter (only audible with an aid) after I replaced the pump (excessive wear on front of pump housing & related shaft wear).

Neither is worth worrying about, IMO, as long as you are getting correct coolant flow & no vapor lock in the fuel system under normal operation.

[N_Rod]

Have you or someone else removed/replaced the heads or gaskets? On some of the Ford engines it is possible to get the head gaskets upside down, This will allow pressure from the cylinder, during the compression stroke, to get into the coolant system.
I cant remember if this is engine specific or all fords are this way. Its been a long time since I have wrenched on ford engines.

[Nitrofueled14]

It's got new used heads, because my old ones were cracked. It's also done it since I replaced the water pump. I don't know if it did it before I rebuilt the engine though.