Differential Liquid, Throttle Body Cleaning, and Broken HEATER!

[JayWildChevy]

Next weekend, I am replacing my spark plugs, changing liquids, and cleaning my throttle body (I have a code, I forget the number, but almost all of the topics online pointed to cleaning the throttle body and changing the sensor).

I'm not experienced with this engine (purchased it in January), so I would love some Tips and How-Tos. Of course, this is the 4.2L i6 engine.

Changing Spark Plugs

What are some tips? Short-cuts, or best practices?


Liquids

I have never changed the differential liquid before. How do I do this? LOL.

Throttle Body

Any best practices here? What is best/safest to use.

Heating

Finally, a few days ago my heat stopped working. When the truck is warm and I'm moving along, I feel hot/warm air when I put my hands up close to the vents, however it sounds like there are no fans blowing. Thank God I live in Texas, now. If I were still in DC, or Hell, Wisconsin, I'd be screwed.

Is this a matter of cleaning the vents or, is it a fan going out?

 

[Wooluf1952]

To clean your T-body:
http://gmtnation.com/forums/topic/10607-how-to-clean-your-throttle-body/

 

[Mounce]

Spark plugs- only use ACDelco 41-103, nothing else.

Differential fluid- 75-90w synthetic.

Throttle body- just about any throttle body cleaner will do, I used the cheapest I could find on the shelf.

Check out MAY03LT on YouTube, he's a member here and has many videos of work on our rides, (spark plug, throttle body, various liquid changes, and many more!)

I'm assuming you don't have 4wd, right?

 

[RedEnvoyDenali]

Next weekend, I am replacing my spark plugs, changing liquids, and cleaning my throttle body (I have a code, I forget the number, but almost all of the topics online pointed to cleaning the throttle body and changing the sensor).

I'm not experienced with this engine (purchased it in January), so I would love some Tips and How-Tos. Of course, this is the 4.2L i6 engine.

Changing Spark Plugs

What are some tips? Short-cuts, or best practices?


Liquids

I have never changed the differential liquid before. How do I do this? LOL.

Throttle Body

Any best practices here? What is best/safest to use.

Heating

Finally, a few days ago my heat stopped working. When the truck is warm and I'm moving along, I feel hot/warm air when I put my hands up close to the vents, however it sounds like there are no fans blowing. Thank God I live in Texas, now. If I were still in DC, or Hell, Wisconsin, I'd be screwed.

Is this a matter of cleaning the vents or, is it a fan going out?

I will try to help with what i know. (as a note there have been several discussions on the this site about all your issues and most recently as well.)

Can't discuss spark plugs on the I-6 since I have a V8

With respect to the differential, since you have a 2 wheel drive i assume you only have a rear diff. My suggestion is to replace the fluid with a good synthetic. Check the manual and put in what it says. That being said "ALWAYS TAKE THE REFILL PLUG OUT FIRST" before draining the diff. It can be a bear sometimes. Again discussed a lot on this site.

The throttle body needs to be cleaned off the vehicle and the most important side is the BACK. Use a throttle body cleaner, not brake fluid, since there are delicate parts and sensors in there. Disconnect the battery before removing the throttle body. The computer needs to relearn the clean throttle body after you are done.

You would certainly be in trouble in my country. This am -29C with wind chill of -39C. By the way it doesn't matter C or F at these temps. Anyway you probably don't have a fan. Try putting on the AC and see if you get any air. If you don't either your resistor pack or Fan motor is gone. Probably will be the resistor pack. It is located behind the glove box and you just need to make sure you get the proper one. Rockauto sells replacements at a good price.

Hope this helps. Use the search for site these are not unknown problems.

While i was typing this both of the above suggestions are excellent.

 

[Mounce]

Here's a link to a playlist of maintenance from MAY03LT for the 4.2.

http://www.youtube.com/playlist?list=PLD76EFDDC2ADF572C

 

[JayWildChevy]

Wow thanks so much!!!!

 

[SmokeyMcBlazer]

Welcome aboard...

I second the "blower motor resistor" as the cause of your "no heater fan" problem. Just replaced the one on my truck last week.

 

[marinegrunt]

I know it's a different vehicle, but my Sierra is known for burning up the blower motor resistor. I've replaced two in two years. I also had to replace the blower motor itself. I'm with the others on the resistor probably being the cause. Check the fuse just to rule out the obvious. I would also get a multi meter and make sure you're getting 12 volts to the blower motor. Before I replaced the blower motor I removed it and put power to it with some wire and alligator clips from the battery just to make sure it was definitely the problem. Check the wiring harness on the motor. Also check the harness on the blower motor resistor. If it's anything like my truck it can get hot and cause it to fail. If you don't have a multimeter you can pick one up for under $5 at harbor freight or for probably less than $10 at Wal-Mart. If you're going to work on your own vehicles a multimeter is a must have.

Mounce directed you to some great info on maintenance so you should be good to go on the other stuff.

If you have any other questions just ask. You'll get a lot of help here and people will walk you through each step if need be.

Good luck!

 

[JayWildChevy]

Thanks everyone so much! I am going to check these out. The heating issue, definitely could turn into something I'd pay too much with a mechanic I don't know, so I'd like to diagnose and do myself.

I will take your advice! It's the worst time for it to go out, but, it could be worse!

 

[Mounce]

Let us know if you need anymore assistance.

 

[triz]

With the differential you can use a cheap harbor freight pump. Synthetic 75w90 for the diff. Just make sure you can remove the fill plug first before removing the drain plug.

Does it blow anything cold or hot? Digital hvac or manual?

 

[freddyboy61]

The OP has a LT model, so probably has the Auto HVAC system that has a blower motor control module not the resistor pack. OP should check fuse #35 in underhood fuse box first. If good, find out if blower motor is getting voltage on purple wire. If no voltage, replace blower motor module.

 

[JayWildChevy]

Thanks all! I replaced my fluids, spark plugs, and cleaned my throttlebody! Cleaning the throttlebody has got rid of the CEL. Its been an hour and 45 miles of no CEL! Feeling the difference!!



About the HVAC: so I checked the AC. Clearly something is trying to come out but no fan to blow it. I will checkout the HVAC tomorrow and follow everyone's recommendations!

You all are great! Thanks! So glad its finally warmer in Central Texas!

 

[Mounce]

Glad everything went well! And dang..that throttle body was NASTY.

 

[triz]

Good job on cleaning that throttle body. For the blower motor. Try and find a used one of a junked Trailblazer. You can probably score one for about 25 -30 bucks. Otherwise your looking at around 120 for a new one that you have to splice in.

 

[Mounce]

I would make sure it's getting power first. Best case scenario, it's the resistor pack.

 

[JayWildChevy]

Hey guys. So, I got in my truck today. The HVAC is working. I did nothing to it. Its blowing strong. Can someone explain this?

 

[JayWildChevy]

And there it goes...it just went out again lol. I think I heard something under the hood when it went out. Hmm

 

[ChrisinVictoria]

Try smacking the blower motor while it is in the on position. If it starts blowing again then the motor is heading south.