LB7: engine heating up no heat in heater

[duramaxstacks]

I just replaced my head gaskets on my 2003 lb7 got the heads pressure tested,put it all back together only to find that its doing the same thing i did the waterpump recently to. the top rad hose pressures up and if i drive it hard at all it starts to heat up but there is never ant heat in the cab ive checked the heater core it fine. Im running out of cash pleaze help if you have any ideas. I would also like to say thanks for everyone who put up posts on changing the head gaskets i couldnt have done it without your help!

 

[dmaxfireman]

whaty did you check the core for?

have you checked for clogs?

do you have an egr system on the truck?

is the thermostat operating correctly?

 

[duramaxstacks]

i thought maybe the core was plugged(no heat in cab) i dont have the egr system and the thermostats seem to be working i just replaced them. i finally bit the bullet and took it to a mechanic to diagnose it. he just called me and figures that the rad is blocked inside. the top hose is hot and the bottom is cold. possibly a new rad is needed? ill pull it out and try to check it any suggestions on how to go about that? thanks

 

[chevyinlinesix]

If it were me, I would pull off the lower radiator hose and start up the truck. Check the flow coming out of the hose. This will tell you how plugged it is/if it is plugged without pulling the radiator (if you haven't already).

I do not know if there is a flow rating for the water pump at idle, but if there is you could remove the thermostats and allow the bottom outlet of the radiator to pour into a pale. Time it for 10 seconds, then measure the amount in the pale (gallons) and multiply by 6, to give you gallons per minute. Even if the waterpump's flow rating is given @2200 RPM or something, just start truck and run at that speed.

This is only how I would do it, maybe someone has a better way though

 

[duramaxstacks]

i ended up pulling the waterpump off i got it done at a shop 6 months ago due to lack of time to do it myself. took it to him and said the pump wasnt working and he told me thats not possible so i pulled it off myself to find the impellor fell off the pump. i think he was trying to get out of warranty work. so for anyone else with flow problems it is possible for the impellor to fall off you can just pull the bottom rad hose off the pump and use a flashlight and i just turned it with a screwdriver.hopefully it saves someone the headache ive had trying to figure it out. now i just need to find a puller for the harmonic ballancer. thanks for the info on the checking the flow

 

[sweetdiesel]

Sorry to hear that atleast u know what's wrong
I recently switched to a electric water pump and couldn't be happier

 

[dmaxfireman]

you dont need a puller for the balancer. just use a 36mm 12pt socket and break it loose once the bolt is out the balancer slides right off.

 

[duramaxstacks]

i got the waterpump changed today trucks runs awsome!! thanks again for the help