Hello again,

I have a 1977 F250 with the 460cid engine. A couple of months back I was driving the truck back from work and it overheated. I nursed it back home by stopping and letting it sit for a while and then adding coolant and water. When I got home I was able to see that there was a leak between the timing cover and the block.

I pulled the front parts off to get to the timing cover. I pulled the water pump and timing cover off as one piece since I had replaced the water pump once already. While I had the timing cover off I checked the timing chain, and I am glad I did. The chain was so loose that it would almost come off without loosening anything. So I changed both gears and the chain.

I put everything back together, and was very careful with the main seal, and the oil pan front seals. I drained the oil, replaced the filter, and added new oil. I then added new coolant. Checked all the levels and fired it up.

Good news is that there seem to be no oil leaks, and the trucks runs pretty well without retiming it yet. The bad news is that there seems to be a secondary coolant leak at the back right of the block somewhere. I couldn't get under it to see where it was leaking. Just that there was coolant coming off the starter between it and the oil pan.

Does anyone have any recommendations of where to start looking, or what might be the most likely culprit?

Thanks,

Donovan

 

Freeze plugs on the backs of the heads? Intake manifold gasket? If you're lucky it might be a heater hose.

 

Sounds like a freeze/core plug....... if true and its a small leak, there are several leak products that you can add and attempt to seal up.... If the plug is eaten thru by rusty corrosion... then it will need to be replaced and depending on the exact plug location things can start to be a pain... but lets wait and see what ya got....

 

A leaking freeze plug on a mod motor looks like this. Same symptoms, little drops of coolant on the oil pan flange. There was a ton of gunk in the block, laying up against the back side of the plug. Probably galvanic corrosion ate through the plug. At least it's the only one I could see and touch on the whole block.




Weeping freeze plug

 

You have good advice so far. A heater hose failure would be something to celebrate. The other items require significant work. Try to do a positive ID on the problem. Avoid overheating the engine. A while back I put some block drains on my 460 so I could do a real cooling system flush. One of the photos shows the original situation with one of the freeze plugs. The other shows the added valve. I had to remove the starter. There are freeze plugs available made from less corrosive materials.