4.0 Coolant Blowing out the overflow on startup

[Patriot1776]

I have a 1992 Ranger 4.0 Automatic 4x4 3.5" Rancho suspension lift in the front blocks in the rear. I recently moved from rainy SW Washington state to frigid E South Dakota.

I had been planning on changing the radiator, hoses, and stat with the first paycheck from the new job. So, I flushed the coolant system before we moved and didn't like the idea of putting an $11 gallon of antifreeze every few days into the truck so I just added water.

BIG MISTAKE!!

The block froze and blew a freeze plug. Got a new one in. 4 miles down the road it overheated again and shredded the upper rad hose.

Changed the hoses, t-stat, and radiator.

Fired it up and it blew the coolant out the overflow tank.

Checked the stat, replaced with another new one.

Same problem.

Checked that stat. Both stats work fine in a pot of hot water on the stove.

Thought it might be a cracked block but then talking with real mechanics and they said it's probably just the head gasket.

What could it be? Are the mechanics right? Or should I plan on a new engine?

 

[kimcrwbr1]

Sounds like a head gasket or a cracked head if your building up pressure in the coolant. run it with the radiator cap off and see if it keeps blowing bubbles. If so you will need to pull the heads and have them magnafluxed for cracks but you can usually tell if the head gasket is leaking there will be a black spot where it should be shiney.

 

[Patriot1776]

Thanks, I just hope it won't be too much to get that done.

 

[Big Jim M]

Question???

Thanks, I just hope it won't be too much to get that done.

Do you KNOW how to fill the radiator on a Ranger? Do you fill it with the engine running and the heater turned to HOT?
If not then that is the problem..
Big JIm

 

[Patriot1776]

yes I did fill it with the cap off and the engine running, the water pump works and the coolant starts to flow in and then the pressure comes and blows it all back out. After I shut the engine off the radiator is only half full and the block seems to be holding some but then again I don't know how to check this for sure.
I even took the heater core hose off that runs to the top side of the block, and filled it up with coolant. I figured that would help make sure the coolant got into the block and the air got out. It seemed to work, the dang thing took about a gallon in before it was full.
I know some leaked out when I put the hose back on but not that much.
Then I filled the radiator and fired it up. I continued to add coolant until it was "boiling" though it was cold.

checked the oil, no foaming or milky color.

the exhaust smells a lot like antifreeze too.

once it warms up though the smell goes away. but it still blows out of the overflow tank.

 

[Big Jim M]

hmmm

yes I did fill it with the cap off and the engine running, the water pump works and the coolant starts to flow in and then the pressure comes and blows it all back out. After I shut the engine off the radiator is only half full and the block seems to be holding some but then again I don't know how to check this for sure.
I even took the heater core hose off that runs to the top side of the block, and filled it up with coolant. I figured that would help make sure the coolant got into the block and the air got out. It seemed to work, the dang thing took about a gallon in before it was full.
I know some leaked out when I put the hose back on but not that much.
Then I filled the radiator and fired it up. I continued to add coolant until it was "boiling" though it was cold.

checked the oil, no foaming or milky color.

the exhaust smells a lot like antifreeze too.

once it warms up though the smell goes away. but it still blows out of the overflow tank.

You evaded the question about turning the heat to HIGH! That is imperative to do in order to completely fill the coolant system.

My first guess here is you didn't get it full the first time and the result is you burnt a gasket or cracked a head...
BUT i'd still refill it correctly and see what happens.
Big JIm

 

[Patriot1776]

Yes the heater was on high when I filled it both times.

Even if I hadn't remembered to do that it still doesn't make sense that the coolant would "boil" though it was still cold.

By cold I mean 50 degrees.

It seems like the pressure is way too high for the coolant to even get into the water jacket of the block.

I don't mean to act cocky or anything but I do want to ask questions and try to gather more information about what may be wrong.

As soon as I can I will be tearing into it and getting the heads checked out.

 

[Big Jim M]

OK!

Yes the heater was on high when I filled it both times.

Even if I hadn't remembered to do that it still doesn't make sense that the coolant would "boil" though it was still cold.

By cold I mean 50 degrees.

It seems like the pressure is way too high for the coolant to even get into the water jacket of the block.

I don't mean to act cocky or anything but I do want to ask questions and try to gather more information about what may be wrong.

As soon as I can I will be tearing into it and getting the heads checked out.

A little compression 101!

The coolant system operates at NO PRESSURE cold.. The engine when started pumps compression into the coolant system thru a crack or burnt gasket. THAT compression can be incredible! It starts coming into the coolant system when started... no matter what the temperature is. As soon as 16 pounds is reached the coolant starts puking out of the system. So even COLD...VERY cold coolant will purge itself from the system.
Big JIm

 

[AllanD]

freezing on the northern plains with pure water?

I'd be really worried about a cracked cylinder wall, which is frankly more likely given the described symptoms.

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