97 7.3, coolant in oil after changed injector cups,

Mercniac · Dec 23, 2016

1997 7.3, I noticed fuel in my coolant so I changed injector cups and everything seemed to go smooth, when I finished I turned the engine over 3 rotations by hand to remove oil, fuel etc from cylinders, it started in about five minutes and ran great but I noticed coolant rising and falling in the de Gas bottle, it got late so I let it sit till the next morning, when I tried to start the engine it felt like it was locked up, I turned it over again by hand three rotations and it started right up, After about one or two minutes I noticed coolant mixing with the oil (i left the valve cover off to watch everything), I shut it off, pulled the injectors and pressurized the coolant system, no leaking injector cups, but after 15 minutes of pressure I noticed coolant rising up through the hole in the bottom of the left front injector cup.
I don't know what happened, I'm guessing something leaked back into one of the cylinders overnight, If I had know it was locked up,again I wouldn't have tried to start it with out turning it by hand again, guess that's when I broke something.
Any info,or advice would be appreciated, this is my daily work truck so whatever is wrong with it I need to fix asap.
Thanks

gnxtc2 · Dec 25, 2016

What sealant did you use to seal injector cups?

Billy T.
[email protected]

78f100 · Dec 25, 2016

Odds are you had some fluid (oil, coolant, fuel) drain back down on the piston and hydro lock. It could have put enough pressure to push the cup up slightly. It's hard to get it all out without pulling the glow plugs and spinning the engine several times with starter.
I would replace that cup, I always let the sleeve retaining locktite cure overnight before I start them.

Mercniac · Dec 25, 2016

I couldn't find specific sleeve retainer sealant where I live so I asked the local diesel shop to sell some to me,but he said he uses red Loctite thread lock and that I should use it also,
I just finished pressurizing the coolant system again, I found no cups leaking on the top edge/flange but I found at least four cups leaking at the bottom flange,, after 30minutes under pressure, four cylinders filled with water, I pumped the water out, then inserted a narrow/twisted piece of paper towel into the small hole in the bottom of the cup only about 1/4" and it was soaked with coolant immediately.
Difficult to detect because it just drips down into the cylinder.
I'm going to replace all eight cups again, and I'll pull my glow plugs this time.
The cups that I put in before are after market, not sure what brand but this time I got my cups and sleeve retainer from Ford.

Thanks for the response

ghohouston · Dec 25, 2016

I believe it is the green 620 loctitw or something like that for injector cups, its been a minute, but it was green.

Magnum PD · Dec 25, 2016

Let it setup also.

gnxtc2 · Dec 25, 2016

I've used the red Lock-tite from Permatex before. Make sure the head is free from fuel, AF and oil.

Also, you have to make sure the cup is seated. Good choice going with OEM cups.

Billy T.
[email protected]

Mercniac · Dec 25, 2016

Thanks for the info and responses, I'm going to change all the cups in the morning, let it set up over night, then pressure test it, I'll let you all know how it turns out.
Thanks again for the help.

Mercniac · Feb 9, 2017

I finished installing the cups, I used oem cups and Motorcraft sealant(spec WSK-M2G348-M5) the diesel tech at the Ford dealer said they use this sealant and after they install the new cups they slowly crank the motor several times to blow out the fuel, oil and debris then install the injectors.It worked good for me. My truck started in just a few minutes and ran fine, I ran it hard all day for about 20 miles, it runs good but it starts slow, I have to crank it for 6-7seconds then it starts and runs strong, it also seems to crank (spin) faster than before when I'm starting it.Before I began this project it would start immediately, as soon as I turned the key. It feels good to have my truck running again but I need it to start like before.
Thanks for the previous help and any ideas about the slow starting issue.

Short Bus · Feb 9, 2017

i use green 620 loc tite bearing mount. After installing the cups and injectors i remove the glowplugs and crank the engine over, then reinstall. I like the truck to sit at the very least 12 hours just to let the loctite cure.

rusty1161 · Feb 9, 2017

Mercniac said:
I finished installing the cups, I used oem cups and Motorcraft sealant(spec WSK-M2G348-M5) the diesel tech at the Ford dealer said they use this sealant and after they install the new cups they slowly crank the motor several times to blow out the fuel, oil and debris then install the injectors.It worked good for me. My truck started in just a few minutes and ran fine, I ran it hard all day for about 20 miles, it runs good but it starts slow, I have to crank it for 6-7seconds then it starts and runs strong, it also seems to crank (spin) faster than before when I'm starting it.Before I began this project it would start immediately, as soon as I turned the key. It feels good to have my truck running again but I need it to start like before.
Thanks for the previous help and any ideas about the slow starting issue.

It usually takes 50-100 miles, sometimes more, to work all of the air out of the HPO system and for your truck to start like normal.

Rusty