EightTrackHits

Below is a thread that I posted when I fluid filmed my 2005. One thing I forgot to mention, fluid film has a penetrant in it. I've used it on "rusty" brake lines before and the next thing you know, they were leaking. I don't know if the fluid film had anything to do with it, but it happened twice. So as for myself, if I'm rustproofing with fluid film, I'll replace rusty brake lines as well. I should anyway. I think you will like the 05 regardless of what route you take. Sometimes it's just good to have an old truck.

Who knows, someone might have just painted it wanting to preserve it a little longer. Perhaps they worked at a John Deere dealer and scored some paint. Some of the stuff underneath (bump stop?) looks relatively new. What made you choose TekTon 44? I have a 2005 as well and really like it. I undercoated mine with Fluidfilm and Fluidfilm Black, but I'll have to recoat that yearly.

I had a similar issue recently and looked at quite a few things. The initial trouble was a visible leak, but I inadvertently installed a cracked head during the repair and had coolant disappearing with no visible leak found or loss of pressure during a pressure check. Coolant was leaking into the head under the valve covers and being dissipated throughout the engine as sludge through the PCV system. since the coolant was being suspended throughout the engine, the oil level was not rising in a direct correlation with the coolant loss. It would steam out the pipe on startup, but after warming up that would stop. Take a look at the underside of your oil cap and tell us if it looks discolored. The initial few posts are not related to your problem, but later the thread gets into something very similar. Hopefully your issue is one of the things txab mentioned. Good news is, I fixed it and still drive it. I will follow your thread and try and answer any questions that I can. You can read my full thread here:

I had a similar issue years ago on an S10 Blazer. Lots of dead plant debris had made it up between the condenser and radiator and I couldn't see it without taking off the condenser.

This answer is likely late by now. Here is a pic from my 05. The angle is a little different than your picture.My take is that if your picture is showing a closed valve, you are likely okay.

The old school trouble shooting techniques are good- when you know you have a problem that OBDII can’t help you with or isn’t helping you with. But old school thought on the new systems (or vise versa) can cause us to chase our tails. I thought my truck was giving me grief with regard to the charging system as I viewed the voltage, but it’s been OK. But, the OP may be having a problem.

I’ve had a very similar tick recently. It was a loose spark plug. I thought it was exhaust, but I was looking around under the hood and saw one of the plugs dancing around.

As Swathdiver said, what you are seeing is likely normal. A good description of the charging system can be found in this post from an Avalanche club. https://www.chevyavalanchefanclub.com/cafcna/index.php?threads/lights-flicker.52489/ The checks that Richard mentioned are worth doing if you begin to have problems, but you may be okay. Read the description of the charging system and see if it jives with your symptoms. But please let us know how it goes.

You’ve started with everything that I would start with. Check grounds of course. Check continuity of the harness from the alternator if you have a schematic and a multimeter. I think this issue is a good candidate for a dealer scan. Please follow up and let us know what you find out.

Something like this? https://m.obd2tool.com/goods-1568-GM+Tech2+GM+Scanner+-CANdi++TIS+(Works+for+GMSAABOPELSUZUKIISUZUHolden).html?gclid=EAIaIQobChMI2YX6mPa89gIVA_3jBx1ERQj0EAQYAiABEgLp3_D_BwE

I took the truck to Eastern New Mexico from Indiana and back over the past few days. No hint of coolant loss! Fuel consumption was good for what this thing is, oil pressure was close to 50 psi at around 2500 rpm on the interstate and about 30 psi at around 600 rpm idle after warming up. So, the repair is good this time. I had the oil changed when I got to NM, the mechanic thought something was really leaking due to the fluid film underneath. I’ll follow up if anything noteworthy happens due to this repair.

A good description of the charging system can be found in this post from an Avalanche club. https://www.chevyavalanchefanclub.com/cafcna/index.php?threads/lights-flicker.52489/ Another thing that could cause the flickering is the battery. Just because a battery is charged to 14vdc doesn’t necessarily mean that it can keep providing current under load if it is unhealthy. Of course this could also just be some random electrical component someplace in your truck. My 05 has the works, heated seats, electric fans, nice radio, and I haven’t noticed any flickering. If you’re issue was not intermittent, and you were closer- we could just swap batteries for a bit. If that didn’t work, you could start pulling fuses to non-essential circuits until you noticed the flickering diminish. There is the off chance that it is in one of the control modules.

Yes, the changing voltage levels that you are describing is normal, but the discernible flickering or pulsing of interior lights isn’t. Is that still happening?

By steadily pulse, you mean that the pulsing or flickering is at a fairly constant frequency, correct? Not random?

Is the battery light still on? I had an alternator problem with a Trailblazer, battery light would not go off, connections were tight. I checked continuity of all the connections to their next assembly and found that the wire carrying the pulse width modulation signal (PWM) was open. The fault was fairly close to the connector and I fixed it with a pigtail I cut from a unit in a junkyard. You mentioning pulsing also makes me wonder if it is in the PWM circuitry, but if it is, it is likely not an open PWM wire as that would cause the alternator to give max output all the time. Good luck and let us know. Another member had similar problem, but he never followed up with his fix: