Head gasket vs injector cup? coolant leak

CTFFEMT · Sep 24, 2015

Hey looking for help and where to start. Recently installed a water meth system on my truck. Last week I got on the throttle hard for about a three second burst. Nothing out of the ordinary seemed to happen but when I got to my destination, I had a good sized coolant puddle under the truck and on the left side of the motor / engine bay. Got back in the truck and drove home, no loss of power, no DTCs, but when I got home, coolant leak again.

Didn't drive it for a couple days. Figured my degas bottle cap failed and got a new one along with refilling some coolant.

Drove it again yesterday, fired up no problem, running smooth but then heard a hissing noise whenever I got on the throttle. Again, got to my destination and had a puddle of coolant under the truck and the passenger side engine bay.

Now with the hood up and my buddy on the throttle, I am able to see that with RPMs 1500 and above, the coolant level in the degas bottle will rise rapidly to the point where it blows past the cap and out the small hole on the outside of the lip on the degas bottle spraying the passenger side of the engine bay.

I am not able to see any diesel in the coolant itself.

no coolant on the oil dipstick.

I had a short ride home so I fired it up and drove home (slow). This time, white smoke out the tailpipe and slight abnormal idle.

I am thinking it has to be either an injector cup or a blown head gasket.

I do not think I have a radiator or coolant system blockage as I am not overheating and at idle, the coolant level remains stable.

Where do I begin??? drain oil? drain coolant? pull valve covers and look for a bad cup?

I do not see any coolant or any fluid leak around the head gasket / where the heads meet the block.

Anything else that could cause this besides head gasket or failed injector cup?

I do have a coolant filtration system, could that be why I am not seeing diesel?

I pulled and rebuilt the motor 2 years ago. I didn't change the injector cups. It does have head studs.

I can provide a full list of mods if needed.

Thank you

Magnum PD · Sep 24, 2015

Compression test would be a start

ghohouston · Sep 24, 2015

Have you tried smelling the coolant for diesel? And I agree on a compression test. Or pull the injectors, and pressurize the coolant system to 16 psi, and check all cups. If you don't see anything, spray dome soapy water on each cup with the system pressurized.

CTFFEMT · Sep 24, 2015

Thanks for the input guys.

I have not done a compression test yet. certainly will asap. working 12 hr overnights this week so will get to it Saturday.

gotta pick up the tool to pressurize the coolant system but will do that.

bruce · Sep 25, 2015

Cups 99% will put fuel in the coolant. They make strips to detect combustion gasses in the coolant. Definitely do a compression test though.

ju015dd · Sep 25, 2015

Plus one on pulling sticks and doing the coolant pressure test. Worked great when I had my issues with not seating cups correctly

CTFFEMT · Sep 25, 2015

getting ready to go to work for the night. going to stop and grab these strips on my way in. picked up a compression tool last night. Still gotta grab the tool to pressurize the coolant system.

CTFFEMT · Sep 26, 2015

Here's under the valve cover. Both passenger and driver side look the same

Working on testing now, see what I get.

A friend of mine brought up another possibility... oil cooler could have cracked / failed mixing oil and coolant and causing the coolant to back up into the degas bottle under throttle. Anyone ever hear of that?

co04cobra · Sep 26, 2015

I would suspect you have a cracked cylinder wall... I know that sucks to hear but only time I've seen the sludge uvc.

ju015dd · Sep 27, 2015

Mine looked like that when I installed cups wrong. Had a couple not get bottomed out on install. Pull the injectors and pressurize the coolant system to see where the leak is.

ju015dd · Sep 27, 2015

I have a tester if you are any where near florida

Jomax · Sep 27, 2015

Autozone has a tester for free rental..

Sent from my SM-N900V using Tapatalk

bruce · Sep 28, 2015

If you end up needing a cup tool holler at me

CTFFEMT · Sep 28, 2015

Thank you guys.

I am in Newtown Connecticut.

I pressurized the coolant system with the injectors in...held 16 psi with no leak.

I know it is not a compression test, but I did an air leak down test with all rockers removed. Cylinders 1, 3, 5, 7 and 8 had very bad leak and cylinders 2, 4, 6 held air just fine. I fear it might be the block.

raining today and I do not have an indoor place to put the truck.

bruce · Sep 28, 2015

Junkyard engine or holler at airfish, he usually has an engine or 2.

co04cobra · Sep 28, 2015

I usually have a few 7.3s around too if you do end up needing one.

CTFFEMT · Sep 29, 2015

Thanks all.

My friend who lent me the tools is coming over today to take a look as well. Always good to get another opinion I guess. He also has a brand new shop and has offered space there for me to pull the motor if needed which is cool.

Should get to the bottom of it for sure today. Of course, I think I already have the answer which sucks.

I will report back.

Another friend has a 7.3 block from a '97 he said I can have but thank you guys.

It's not even bad to pull the 7.3 motor, it's just that damn ZF6 i am dreading. Oh well. Break, rebuild stronger, repeat I guess. Gotta pay to play.

what is the consensus on filling the block vs engine girdle? If I do this again, I don't want to crack another.

Magnum PD · Sep 29, 2015

You can do a partial fill and be fine. Girdles are ok, not the cure all.

Cropp148 · Feb 15, 2022

ju015dd said:
Mine looked like that when I installed cups wrong. Had a couple not get bottomed out on install. Pull the injectors and pressurize the coolant system to see where the leak is.

I think I'm experiencing th we same problem as you had with not getting the cups seated all way I have no oil in the coolant or fuel just pressures the cooling system to where it starts pushing coolant out of the dagas bottle