Help me out?

[gmcyukondriver]

Ok, so my truck has been having a couple minor issues lately that I want to get tracked down and taken care of.

1. The infamous heater core gurgle. Could someone let me know how to diagnose if the heater core is bad? Is there anything else that would cause this? Sounds like a waterfall behind the dash every time I accelerate from a stop. It's getting annoying. I'm also pretty sure my thermostat is stuck wide open, so I'll be replacing that soon. Is there an easy way to make sure you get all the air bubbles out of the cooling system?

2. Starting issue. When I start my truck, it fires, then the RPM's drop, and it seems like it's going to die. Around 200 RPM. If I give it a little gas when it does this, the RPM's kick up, and stay around 700. Sometimes the idle surges a little bit, until I drive it, then it smooths out and drives and idles fine. No problems. But if I shut it off, and start it again, most of the time it does the same thing. I'm not getting any codes. I'm thinking it's either my Throttle Position Sensor, or it's my fuel pump (original with 200k miles) finally giving up the ghost. Anything else I should look at? Injectors leaking maybe?


Thanks all, I'm looking to get this thing dialed in and running as well as I can before I bite the bullet on getting it tuned. Transmission is going to have to be rebuilt soon too (Also original, never rebuilt with 200k).

 

[JK360]

Not sure about the idle issue but the heater core sounds like it has an air pocket in there. you need to "burp" it. You can search the web on how to do this but what i do is park the truck on ramps or park it facing up hill. With the truck cool, take the cap off the radiator and start the truck. Let it run and warm up and gravity should move the air bubbles out of the radiator. when the tstat opens the fluid level might drop down in the radiator. if so just top it off and close the cap. that should do the trick.

 

[someotherguy]

The air pocket will be because of a leak. Find the leak and fix it before it becomes serious.

Richard

 

[dowsewashere]

The idle could also be a iac, vaccum leak, or a throttle body that has carbon build up and wont let it close.

 

[gmcyukondriver]

Not sure about the idle issue but the heater core sounds like it has an air pocket in there. you need to "burp" it. You can search the web on how to do this but what i do is park the truck on ramps or park it facing up hill. With the truck cool, take the cap off the radiator and start the truck. Let it run and warm up and gravity should move the air bubbles out of the radiator. when the tstat opens the fluid level might drop down in the radiator. if so just top it off and close the cap. that should do the trick.

Thanks, I'd heard of that before, just wasn't sure what the actual method was. I'll give that a shot, but we don't have hills. Have to settle for jackstands.

The air pocket will be because of a leak. Find the leak and fix it before it becomes serious.

Richard

Is there any way to narrow down where it might be leaking? I haven't seen any coolant, but it was in a bad accident last year. I don't think the radiator was damaged, but it could have been. Do you think I should have it pressure checked, or is there more I can do before that?

The idle could also be a iac, vaccum leak, or a throttle body that has carbon build up and wont let it close.

Yeah, I've thought of those, but the throttle body gaskets are fairly new and in good shape. I just recently took the throttle body off, and it didn't look too bad. I'm planning on taking it apart and doing TBI mods, cleaning it, and doing a rebuild on it in the near future. Hopefully that will take care of it.


I have a fuel pressure gauge also on the truck, so I'll let you guys know what it says about my pressure on startup. Thanks for the help. I want to get this all squared away before the holidays.

 

[95Escahoe]

My heater core was making the same sound, replaced it and never made sounds since

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