1994 f250 power stroke 4x4 5 speed loosing coolant

My 1994 f250 7.3 water pump started weeping so I replaced it and the thermostat and now it is over heating and pushing the coolant from the radiator into the resivor. And when I drive it'll stay at a decent temp but it's loosing coolant the whole time. And then when I get out to check the coolant the resivor is full and the radiator is dam near empty or will have some in it and slows drain into the motor once the cap is off. Anybody have some info on this. Really hoping it's not a head gasket because it ran just fine before the new thermostat and water pump


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What thermostat?

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I'm not sure what it is,I just told the guy what year my truck was and he gave me one


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Was it physical the same size as your old one?

The last time that I changed out my water pump I fought a leak and found it on the O rings on the heater hose fitting. Also the thermostat housing has a habit of warping and leaking unless you replace it also or get the flat metal flange kit to fix it off of Ebay, do a search on "Powerstroke Thermostat" There is also a vendor that sells them but I can't remember who it is.

You are going to have to get a pressure tester and put it on after you clean everything up to see where it is leaking, it can be a bear to find it. You can rent a coolant pressure tester at Auto Zone.

I just bought another thermostat and replaced it. Fill up the radiator and almost as soon as i start the truck it is pushing the fluid out of the radiator and into the resivor. So I unplugged it and put my finger over the hole and it started pushing it out from under the radiator cap. And it's not leaking any where until it fills the resivor then it's pushing it through the cap of the clear resivor tank


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See if there is pressure coming from radiator hose hooked up to engine.

https://vimeo.com/175782316


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Magnum PD said:

See if there is pressure coming from radiator hose hooked up to engine.

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As in take the upper radiator hose off while the truck is running?

If it isn't leaking from any other place and it starts as soon as you start the engine I would suspect compression gases or injector cups, but leaning heavy on compression gases.

Does the coolant smell like diesel?

Bugman said:

If it isn't leaking from any other place and it starts as soon as you start the engine I would suspect compression gases or injector cups, but leaning heavy on compression gases.

Does the coolant smell like diesel?

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No it doesn't smell like diesel. So what does that mean? Head gasket or oil cooler is plugged?

Oil cooler plugged wouldn't have anything to do with it.
After sitting, how does the coolant in the radiator look? Like oil film on top? Black soot? Etc

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You need to pressurize the cooling system when the engine is cold and see where you are loosing coolant from. If not somewhere that you can see it then it is going to be somewhere that you can't. Have you looked at your oil to see if there is water in it? It might look milky or different than regular oil. You might also take one of the valve covers off and see what the oil looks like on the lifters to see if it looks milky or has a lot of water in the recesses.

Make sure you got the correct water pump and correct thermostat. If you mixed up the water pump and t-stats, you will screw up the coolant flow through the block.

Please post the part number for the water pump and t-stat. Is the t-stat a long or short stem?

Billy T.
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I just remembered when I got my water pump there was 3 options depending on what the 8th letter on my vin # was. And so I got them the info but when I went to put it on it was a different thickness. I had to use half of the new bolts that came with it and half of my old ones. But everything lined up fine? Could I possibly have the wrong water pump?


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Where did you get the pump from? What is the part number? Long or short stem t-stat?

Billy T.
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gnxtc2 said:

Where did you get the pump from? What is the part number? Long or short stem t-stat?

Billy T.
[email protected]

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I don't know the part number for the water pump i can look when I get home, do you know the location of the part number? And I also don't know if it's a long or short stem t stat, it looks normal so probably short

Oil coolers are rarely the problem it's not a 6.0. Ask a friend or find at parts store tester that goes over radiator cap that changes color when exposed to combustion or pull glow plugs and do cylinder leak down test. Head gaskets are an issue if heads were pulled at some point

gnxtc2 said:

Make sure you got the correct water pump and correct thermostat. If you mixed up the water pump and t-stats, you will screw up the coolant flow through the block.

Please post the part number for the water pump and t-stat. Is the t-stat a long or short stem?

Billy T.
[email protected]

Click to expand...

X2

Always go back to the last thing changed when a new problem develops.

It COULD be an engine compression leak, but don't go there until you are sure you have the right combination of water pump and thermostat.

94 and early 95 used a different water pump and thermostat. If you have the later water pump and early thermostat, the coolant is not circulating and has almost the same effect as a thermostat stuck closed as far as rapid overheating goes.

As I recall the late model pump takes a long stem thermostat, if the early short stem thermostat is installed it doesn't cover the re circulation port so coolant stays in the block and does not travel out to radiator even after thermo opens. Then the coolant in block expands since it is about to boil and pushes coolant out into overflow.

If it was truly fine until you changed the water pump it has to be related to water pump. UNLESS it ran low on coolant before changing water pump and cracked something.