pressure in the coolant system

[DIESELMAFIAPER.LB7]

Well I noticed tonight when i got home my upper radiator hose was hard now my question is do you guys think that I might have cup issues cause I have arp studs an this issue started with 15k on the rebuild so I don't know we're to start checking first I really hope it not a headgasket issue

 

[Righteyeblind]

Do you have coolant coming out of the overflow?

 

[SgtKilroy]

I'd check the bleed off hose on the tank for blockage, especially if it's been a while since you changed your coolant, etc. I hope that's it, instead of injector cups anyhow. Good luck.

 

[sweetdiesel]

quickest way is to pull the glow plugs and pressurize the systym. leave it for a while or even over night and crank it over ( be carefull ) but check for coolant coming out of the gp holes.

 

[DIESELMAFIAPER.LB7]

Well it doesn't puke coolant unless I take the cap an loosen it then it will but it doesn't build pressure instantly I let it bleed off pressure then put The cap back on an took a drive only had tiny bit of pressure like it should but over time it seems to build up lots of pressure

 

[DIESELMAFIAPER.LB7]

could a fualty cap be letting it build up to much pressure?

 

[Mike_S]

Doubt it. Remember when I asked you if you wanted to go ahead and re-seal all of the cups when you had it apart last time? Now you know why. Shitty deal is no matter what test you do you can't really determine if it is head gaskets or injector cups...

Nice avatar by the way...LOL!

 

[DIESELMAFIAPER.LB7]

I was hoping it wasnt true ill limp it till the new project is done if its a cup you get that pic I sent you?

 

[duramaxdiesel]

I've seen a fautly coolant cap do this too. I hope it's that and not a cup or headgaskets. Good luck, man!

Nick

 

[DIESELMAFIAPER.LB7]

Well after driving with a new cap I haven't had the pressure build up still maybe that cap was my issue I hope at least I know its not headgaskets just no possible way unless the gasket had a factory **** up

 

[jonathancasey19]

Correct me if I'm wrong but I thought you do not want to remove the cups and reseal them PERIOD unless they accidentally come out when swapping injectors?

 

[Mike_S]

Correct me if I'm wrong but I thought you do not want to remove the cups and reseal them PERIOD unless they accidentally come out when swapping injectors?

The issue is that they are not "sealed" from the factory, IE they don't actually apply any kind of sealant. Also, the cup can unseat and not completely come out of the head when removing injectors. These 2 reasons are why I have removed all of the injector cups in my heads and plan to completely clean all the surfaces and apply a sealant to all 8 cups. Hopefully this will aid in avoiding any issues in the future.

 

[Sledhead]

When I did my top end the machine shop pressure tested the heads before doing the machine work (cups need to come out to plane heads). I had them install cups and then pressure test them again. Mine are good so far but its only been running 40 min

 

[S Phinney]

The issue is that they are not "sealed" from the factory, IE they don't actually apply any kind of sealant. Also, the cup can unseat and not completely come out of the head when removing injectors. These 2 reasons are why I have removed all of the injector cups in my heads and plan to completely clean all the surfaces and apply a sealant to all 8 cups. Hopefully this will aid in avoiding any issues in the future.

How do you know they are not sealed? How does it not leak if they are not sealed?

 

[ripmf666]

When I did my top end the machine shop pressure tested the heads before doing the machine work (cups need to come out to plane heads). I had them install cups and then pressure test them again. Mine are good so far but its only been running 40 min

When the heads are trued up they should take the same amount off each cup also.Along with setting the valve into the seat the same amount that was removed from the head surface.

 

[Sledhead]

When the heads are trued up they should take the same amount off each cup also.Along with setting the valve into the seat the same amount that was removed from the head surface.

Hmmmm.....gulp

I don't think this was done, it definitely was not mentioned by them. I think they took .003 and .005 off and told me the service limit was .008. They used the original (100,000 mile) valve springs and installed new valve seals.

I used the same GM gaskets which I removed; a "C" and a "B".

 

[JoshH]

How do you know they are not sealed? How does it not leak if they are not sealed?

Yeah, and what is the crap that is all over the cups and the sealing surface in the head when they are pulled out?

 

[S Phinney]

The valve pocket area is about 6 cc and should be maintained as well as valve spring seat pressures. I don't think it is necessary to take any off the injector cups themselves though. They won't hit the piston because there is enough clearance in the quench area.

 

[JoshH]

I think I remember seeing a spec on head surface to valve measurement. I'm sure it is posted in the GM Spec area. As long as they still fall within the range, I don't think it is necessary to do any work on the seats.

 

[NLDP]

You would want to have valves cut in if your piston to valve clearance is an issue . We always use the thickest gaskets available hence no issues , and it also drops compression slightly by using the thick gasket . Nldp