Hi, I have a 1999 Dodge Ram 1500 5.9 and I am losing all of my coolant from the back of the engine. It happened all of a sudden, I was driving it and started hearing an odd noise and by the time I stopped, all of my coolant was on the ground or steaming off. I don't know exactly where the leak is, I can't see it but it is draining out of the bell housing. I was reading some other forums on here similar to this problem but they were all for slow drips or leaks but as soon as I put coolant in, it all runs right back out. My guess is maybe a freeze-out plug because I can't think of anything else that would allow that much coolant to drain so quickly, even the intake manifold would likely be a much slower leak. The heater hoses are fine and there is no visible leak from the top of the engine.

Sorry if a similar post exists somewhere else, I am brand new to dodge forum and am still learning how it all works.

If anyone has any suggestions it would be very appreciated.
Thanks,
Luke

 

There are two freeze plugs on the back on the block. Unfortunately, either the engine, or the trans, needs to come out to get to them. Two different sizes as well.

If you have one that has failed, odds are, the rest aren't far behind. May not be a bad idea to change ALL of them. Go with Brass.

 

Sounds like an expansion plug has failed. Unless you bought the truck new, I'm pretty sure somewhere along the line, someone didn't keep the coolant fresh. It needs to be changed every three to five years. The anti-freeze part never goes away if you don't add water. The anti-corrosion only lasts 5 years at most. This keeps the dissimilar metals from setting up electrolytic corrosion.

I'd pull the engine and replace all the plugs. I'll bet you find a few more soft enough to poke a screwdriver through. This would also be a good time to flush the block with a garden hose. You'd be surprised how much sand, rust flakes and general junk will come out. If you have well over 100,000 miles, I'd replace the timing chain while you're at it. Maybe a high VOLUME oil pump too. Don't go high pressure. That will blow your bearings out.

 

It ended up being a bad intake manifold gasket, All of the freeze plugs were good. I am still somewhat confused as to how that much coolant was draining just from an intake gasket though.
Thanks for the reply,
Luke

 

Thanks for letting me know about the coolant life, I did not know that you had to replace it that often but I will keep that in mind from now on. It ended up being an intake manifold gasket though, the freeze plugs must have been replaced when the transmission was rebuilt so it was a waste of time to remove the transmission, but oh well. I still don't know how a bad intake manifold could allow that much coolant to drain so quickly but apparently it can.
Thanks,
Luke

 

There is a coolant passage right in the back of the head