hmmwv blowing water out of overflow tank ???

[jcappeljr]

I picked up another hmmwv project.I was a non runner.The water pump was locked up,so I replaced the water pump.When I started it up it blows water out of the overflow tank.I guess that means the head gasket blew or it has a cracked head.Any ideas ???

 

[usmc81301]

I have seen this before and it is one of the two problems you already identified.

 

[papakb]

Are you sure you got the correct water pump? Remember the 6.2 and 6.5 don't rotate the same way.

 

[chevyCUCV]

What if you take the rad cap off?

 

[jcappeljr]

I dont know if I got the right one,if you take the cap completely it blows coolant out.

 

[nf6x]

I had coolant coming out the overflow pipe when my HMMWV developed blown head gaskets and cracked heads a number of years ago. The symptom was weird; it seemed like it was making more water as it went. It turned out that the smaller tubes that run from the surge tank to high points in the coolant system were also clogged with rusty crud. Since the water levels couldn't equalize with the help of those tubes, the leaking exhaust gasses pushed water down through the engine block then back up through the surge tank. We couldn't even check for exhaust gas with a block checker, because coolant would foam up and foul the checker faster than we could get a good air sample into it.

 

[jcappeljr]

thanks for everyones help.

 

[dilvoy]

Are you sure you got the correct water pump? Remember the 6.2 and 6.5 don't rotate the same way.

The old style and the reverse rotation water pumps as used on serpentine belt engines are shaped differently so the plate that they bolt too have matching holes for the style of pump that they work with.

 

[Adrian A]

Head gaskets or crack or warped heads. Any water in the oil? You should drain the oil and see. Also a leak down test with no coolant will help to diagnose a bad gasket or head problem.

 

[jcappeljr]

No water in oil,what do you mean by a leak down test?

 

[pigfoot63]

Remove your glow plugs and see if you have coolant coming out of any of them, If you do you probally have a cracked head or a blown head gasket. Also make sure you have the proper water pump. The ones for the serpentine system are reverse rotation.

 

[Adrian A]

You use a compression test gauge to see how fast the cylinder leaks air. A compression test will help too.

 

[Adrian A]

It is a diesel and has no spark plugs. Perhaps you can pull the glow plugs and perform the test. I'm not terribly familiar with diesel's.

 

[papakb]

A typical symptom of a blown head gasket is bubbling in the overflow tank when the engine is running. There were a whole series of HMMWV engines with weak sidewall castings in the #8 cylinder but I think this is only related to early turbo engines. If you have an original 6.2 that's never had the heads off there's a good bet that gaskets are the problem. The leak down check is where you use a hand pump and pressurize the cooling system and then look at the rate that it loses pressure. It should take a minute or so. If the pressure falls off immediately were back to gaskets.

There are a couple of products that can help minimize coolant system troubles. Red Line Water Wetter improves heat transfer in the radiator and helps keep system corrosion under control. Use a good diesel coolant addative when you top off again. They're different that gas engine coolant inhibitors.

Kurt

 

[jcappeljr]

Thanks for all the help guys.

 

[jcappeljr]

I pulled 1 glow plug,no water in it.

 

[pigfoot63]

You may have to pull all 8 glow plugs to check for coolant.