I just bought a 1987 f-250 and it seems to overheat and boil coolant after it reaches operating temp. The previous owner replaced the radiator and the water pump as well as some coolant lines and the problem still persisted. The oil is not creamy or milky and there is no oil in the coolant so I’m leaning away from a blown head gasket or something major inside the engine. Has anyone had any issues like this or know what could be the culprit?

 

Has the thermostat been addressed? Is the fan shroud in place? Does the fan seem to turn fast?

 

The fan spins fast but the fan shroud is off currently. It had the issue even with it on. It also seems to build pressure in the system but I’m assuming it’s because of the boiling coolant. I have not checked the thermostat yet but I do know that the heater core is not hooked up. The line just loops bypassing it. Have a new one just haven’t put it in

 

a bad radiator cap will cause the coolant to boil.

 

It’s a brand new radiator and cap. Unless it came defective

 

You will always build pressure in the system from the natural heating of the coolant. I would certainly replace the thermostat and make sure the air is then bled from the system. Without the fan shroud you would need to be driving around 40 to 50 MPH or faster to naturally force the air through the radiator.

 

this right here, fan shroud is absolutely needed to better direct air through the radiator, not having one in place is probably making the problem worse.

 

I will try a new thermostat and bleeding the system after re installing the fan shroud.
and should it be ok to test the system with water first before possibly loosing gallons of coolant again?

 

Yes just water will be fine. I found that removing the uppermost heater hose at the engine end and adding coolant until it runs out there is a good way to get most of the air out of the system.

 

I re-installed the fan shroud and bled the system and there is still some issues. It doesn’t overheat as easy now but when you turn the engine off it seems like pressure builds quickly and escapes through the coolant bottle by pushing or boiling fluid out. I also noticed that the fan is blowing away from the engine and not towards. I’m wondering if someone installed the belt wrong and that could also be part of the issue.

 

I suppose a lot of things are possible. Possibly the fan is bolted on backwards. Which engine do you have?

 

Post a picture of the fan belt routing. It sure sounds like the belt is on wrong.

 

I checked the belt routing and it was wrong. It also looked like the wrong belt tensioner was installed. The one on there was for a flat belt not a v belt. There is also and empty bracket at the top of the left side of the engine with the alternator right below it. Do I need a special belt or am I missing a component? I’ve heard about a smog pump delete but can’t really find much info on it. If anyone has pictures of how the engine should look with the belt routing could you please share it. Thanks again

 

I can't help you with the belt routing, but if someone can they will need to know which engine you have?


If the fan pulley is turning backwards the water pump would also be turning backwards.

 

I found out that the radiator wasn’t an exact fit for the truck and had an extra open port up by the cap that was open. Every time the system would heat up or try and build pressure it would spit coolant out that hole. I plugged the hole and no more overheating or boiling coolant!