I had my "new" truck (93 F350) in for some service work and state inspection. They found that with the radiator cap off the coolant was bubbling alot. He told me he was thinking head gasket. So he pressurized the system to 15 psi and left it overnight in the morning it was at 5 psi. He then added some kind of dye to the coolant that exhaust gasses are supposed to change the color if they are present. It did not change. He said he believes it has a leak somewhere but at this point hes not sure which side of the engine it would even be but hes still thinking it will need head gaskets. He finally told me to just drive the truck and keep an eye on temp gauge and be prepared to do head gaskets at some point. This gentleman is an old mechanic who's seen and done alot so I trust him. I guess my question is has anyone had similar troubles before? And could it be something else? It doesnt seem to get hot at all under normal driving. I was planning to use the truck for our travel trailer puller but Im a bit hesitant now as to if thats ok or not at this point.

On a side note of less importance---I cant get my overdive button on shifter to work or light up.... I took the steering cowling apart----wires look fine and I had my test light light up so I tried a new button---still nothing. If anyone has a thought on that i'd appreciate it as well. Thanks

 

I would ignore it and just keep an eye on the temp gauge like you should anyway. If enough compression was getting into the cooling system to cause such bubbling, you would have a much bigger problem like water in the oil.

I don't even know what he means when he says the radiator cap is bubbling. If you had a bad head gasket, you would see bubbles in the coolant while the engine is running. I would say a bad radiator cap is more likely based on the very limited info I have here.

 

I meant the coolant was bubbling with the engine running and radiator cap removed. No water in oil at all---I just changed it about 100 miles ago and the old oil was clean and the new stuff looks like I just put it in.

 

Well that is quite a different thing. NOW it sounds like a head gasket.