Blitzkrieg3002

So about a month ago i started noticing my heater becoming less efficient, the heat started blowing colder and colder and i thought that perhaps i was low on coolant/water and this was the reason i had low heat. maybe my engine was starting to run dry. Since then i've been checking my water levels every week and every week it takes less than 1/4 jug of water to top it off but does take a little each time i check.

next thing is about 2-3 weeks ago i started noticing a speratic bouncing idle upon start up that stops once the vehicle reaches normal operating temperature. after checking the heater this morning after a 30 minute drive engine heat gauge in the dead center between C and H and my heater is blowing warm/cold air it is a bit warm so SOME heat is coming out but VERY minute.

about 4 months ago when getting the vehicle smogged i did have to replace the cat and both o2 censors and i did a full tune up during this time replacing plugs, wires, air filter, oil change, etc. was running perfect until this started happening.

this morning i popped the hood after verifying the air from the heater is still cold and grabbed the hose going to and from the heater core and both of them are hot/warm, not as hot as i would think they should be but both do have some heat.

one more thing is that about 2 months ago my check engine light came on and i pulled the codes... i forgot the exact code number but it was one regarding the EGR... i took the cap off one of the egr pieces and blew some air through the filter/cotton looking piece and put it back in and the light went away and the truck ran good. i havn't pulled the codes since or seen the check engine come back on since.

i've done some searching around the forums and am thinking maybe some air is getting into my cooling system somehow. and if so how? it would make sense if air is getting in because i hear that that would cause the bouncing idle problem as well as it would cause my heater issue of low/no heat as water would be having a problem getting into the heater core... ive noticed people talk about burping the system... how does one go about doing this?? also if anyone has any idea how air could be getting into my cooling system or has any other idea what could be wrong based on my description feel free to post. thanks in advanced

~Rick

fierohink

Well to burp the system you make the rad cap the higest point on the system by jacking up the front end. Then you run the truck with the cap off and add fluid as needed in to the rad

You can also do some diagnostic on your heater core. Unplug the two line going to the core, then connect a garden hose to one side and observe what goes out the other pipe. If you only get a trickle out through the core then you know you have an issue there, or if lots of water comes through then you can be pretty safe it isn't a core plugged up.

If the core is good and you are able to top of the coolant, next check the cable the comes through the firewall to open the portioning valve before the heater core, check that the door is openning to the heater box to allow air through, I'm assuming the blower fan is still working, when was the last time your thermostat was changed? How about a coolant temp sensor? Fan clutch stuck on i.e. overcooling the truck?

fierohink

Make a check list of what can cause these problems and start clearing out the easy and cheap ones.

Blitzkrieg3002

awesome, the more i think about it. the more i'm thinking that there is some air stuck within the cooling system it's been so long since i've done a burp to the cooling system now that i know what that is. and i've added/removed water from the system multiple times. so i'll try this first and see what happens. i have verified that the linkage is opening and closing the heater hose/actuater. so this is working properly as well the ac/heater fan is working as intended. clutch fan stuck on? not sure what that means. perhaps the fan behind the radiator that cools the system? if so no it's not stuck on i can hear it during hot season actually kick on.. the vehicle is running at normal temperature as the heat gauge shows dead center between C and H... i did read about the cooling sensor as well this could be the case i will probably go to checking this after burping the system and flushing the heater core. Thanks for the tips

Blitzkrieg3002

yep. burping it did the trick turns out it was just an air pocket stuck in there somewhere trucks running good again heaters working, and rpm's aren't bouncing all over the place. thanks fiero