LB7 Coolant issue.

[Atouchofgrass]

Well for about a month now i've been having a coolant issue with my 02 reg cab lb7(The truck currently has 167k). Their are two things that pop into my mind that it could be, injector cups, or head gaskets . It spends most of it's time towing a trailer during the week, but some days i come home with a full coolant bottle, some days it's low and the coolant light comes on. Some mornings, the system is pressurized, with low coolant, other times it full and no pressure in the system. I literally am at a standstill. I'm gonna try and do a compression test this week, but the funny thing is it definitely not burning it, and the oil level is fine along with looking perfectly fine. It run's like a top, and no overheating at all. I just don't want to run this truck any longer with this happening especially since winter is approaching, and it will be used for plowing. Any input would be greatly appreciated! :thumb:

 

[Relentlesscummins]

Sounds like head gaskets

 

[blk smoke lb7]

Mine did the same thing and i did new gaskets and pulled all injector cups and resealed them and problem solved.Make sure you use the high temp red loctite its not the easiest to find but its good to 500 degrees instead of only 350 for regular loctite.Henry and Darryl can hook you up with studs and gaskets pretty cheap.Good time to port the heads while your in there

 

[Kspen90]

A good test of the cups/gaskets would be to let it sit all night, then make sure the coolant system isnt pressurized by opening the coolant resivoir cap and retighten it. Then start the truck while its stone cold and immediately power brake it in the driveway for about 20 seconds then pop the hood and open the cap and see if the coolant system is under pressure. If it is then you definitely have combustion gasses entering the coolant system.

 

[RPM Motorsports]

immediately power brake it in the driveway for about 20 seconds

Thats a good test for the converter too

 

[jraymer]

yea I don't think I would ever power brake my stone cold truck for half a minute.

 

[TeaBagger2006]

kspent..... who told you that?

 

[Atouchofgrass]

Never heard of that, knowing my luck it is head gaskets..

 

[Kspen90]

kspent..... who told you that?

Nobody, its a process of logic. If the coolant is cold then there will be no "steam" pressure from the coolant getting hot and expanding. When you power brake it (and when i say power brake i dont mean put both feet flat on the floor and roast the tires, i mean give it slight throttle while pushing the brake to put a load on the engine to increase cylinder pressure) if there is a head gasket or lifted cup then the cylinder pressure will escape into the coolant system causing pressure.

 

[bullfrogjohnson]

Put the overflow line into a bottle and drive it. If there is coolant in there after driving the truck real hard then odds are its cups. If there is no coolant after beating on it hard and the radiator hoses are still hard then its most likely gaskets.

You can also remove all the glowplugs and pressurize the coolant system and let it sit over night. The next morning look for coolant seeping out of the holes. You can narrow down which side it is and what cyclinder. Tear that side down and remove the injector cup of the suspect cylinder. If the bottom of the cup has soot trails then I would reseal the cup and put it back together. If no soot then keep on digging until the head is off.

 

[05dmaxdriver]

my dads 02 lb7 is doing the same thing , hard upper rad. hose low coolant light on at time after driving .

 

[Atouchofgrass]

I'm leaning towards gaskets only because i know it isn't leaking out of the coolant overflow because their would be coolant all over the passenger fender well... It's playing mind games with me because some days it's perfectly fine and some days its down coolant. What is whacky, when i do release the pressure from the degas bottle the coolant is at a normal level. Could it even be a bad bottle cap?

 

[Kspen90]

I would try changing the thermostat and cap before doing any major repairs

 

[blk smoke lb7]

no way its the cap IMO mine did that and i tried 3 different caps and it still did it i also kept pulling injector cups and resealing puting it back together and still having a problem Get the studs and gaskets injector o rings reseal all the injector cups put it back together and then its back to rollin coal:thumb:

 

[Atouchofgrass]

I know, i just don't want to quit trying :rofl: Might as well do all eight injectors while im in there.. I did a balance rate test and two are out of spec, great :roflmao:

 

[blk smoke lb7]

Injectors is another issuse and 3 times the cost of head gaskets that sucks

question replace just 2 or go with all 8?

 

[Atouchofgrass]

I'd love to do all eight, but financially it would really suck!

 

[blk smoke lb7]

I'd love to do all eight, but financially it would really suck!

I hear ya i did mine last year,no ky was used :rofl:

 

[02greysixer]

I hear ya i did mine last year,no ky was used :rofl:

X2, I still have to sit down very slowly oke:


Sint frum tha orijinul smert fone

 

[Atouchofgrass]

I know, sure is gonna hurt! Better try and prepare. :rofl: