Immortalis
Full Member
- Joined
- Jun 9, 2018
- Messages
- 14
Hi all.
I've got a 2005 Avalanche 1500 4wd 5.3l
About 2 weeks ago the truck overheated. All the signs (what little there were) told me it was the water pump,even though I replaced the water pump 6 months ago. I tried some other things though first.
- Hooked up the ODBII scanner - Wasn't connecting
- Tested for leaks - None found
- Checked (MOST) of the hoses for cuts/leaks - None found
- Checked for good coolant flow throughout the system (as best as I could with minimal tools and knowledge) - All looked good
- Replaced thermostat - Made no difference
- Removed thermostat completely - Made no difference
By this time, I wasn't very confident it was the water pump anymore but I was running out of thoughts.
I took the truck to a shop to get them to figure out the problem. They said they pressurized the system and it held pressure and nothing leaked out. They then said they best guess was the water pump was bad.
So... I bought a new water pump. In removing the old one, I found one of the hoses WAS cut. (despite holding pressure and not leaking?!?!). The little 3" hose that connects to the water pump was slit on the under side. So I replaced that, but in doing so, broke the Y connector. So, I replaced the Y connector and since I was at it, replaced the hose from the Y to the surge tank. I then installed the new water pump and re-installed the new thermostat as well. - All of that made no difference.
When I was replacing the water pump, I remembered that the ODB port was connected to the cigarette lighter fuse (which hadn't been working in quite awhile), so after installing the water pump I replaced the fuse and the port was working again. My scanner came back with 2 codes... I forget what they were but the first one was a bad ECT sensor. I replaced that and it helped a little bit... Instead of overheating in 4 minutes, it now takes about 6 minutes. Replacing the sensor cleared both codes though (whatever the 2nd one was).
I'm running out of ideas here (and money)... and was hoping someone had any thoughts?
Just some more random info that may or may not be of use...
- I have been trying to burp the system after adding coolant (several times a day), even though its a pressurized system and doesn't require burping.
- Anytime I say "coolant" I'm referring to water. I've only been putting water in until I solve this, then I'll go back to Dex-Cool.
- There's no coolant leak, but I do lose coolant when it overheats. The mechanic said it's it's an aluminum rad with plastic end caps which act as a pressure release so when it gets too hot, the pressure (and coolant) are ejected from there.
- My rad has no rad cap and no petcock
- Since all this started... my truck now chokes a bit trying to start up... but aside from the choking, she sill starts fairly easily.
- When it starts, there's a puff off white or greyish smoke that comes out the exhaust.
- Since this started, the truck now rides pretty rough if I exceed 70kmh
Thank you all for reading and for any input yous may have.
I've got a 2005 Avalanche 1500 4wd 5.3l
About 2 weeks ago the truck overheated. All the signs (what little there were) told me it was the water pump,even though I replaced the water pump 6 months ago. I tried some other things though first.
- Hooked up the ODBII scanner - Wasn't connecting
- Tested for leaks - None found
- Checked (MOST) of the hoses for cuts/leaks - None found
- Checked for good coolant flow throughout the system (as best as I could with minimal tools and knowledge) - All looked good
- Replaced thermostat - Made no difference
- Removed thermostat completely - Made no difference
By this time, I wasn't very confident it was the water pump anymore but I was running out of thoughts.
I took the truck to a shop to get them to figure out the problem. They said they pressurized the system and it held pressure and nothing leaked out. They then said they best guess was the water pump was bad.
So... I bought a new water pump. In removing the old one, I found one of the hoses WAS cut. (despite holding pressure and not leaking?!?!). The little 3" hose that connects to the water pump was slit on the under side. So I replaced that, but in doing so, broke the Y connector. So, I replaced the Y connector and since I was at it, replaced the hose from the Y to the surge tank. I then installed the new water pump and re-installed the new thermostat as well. - All of that made no difference.
When I was replacing the water pump, I remembered that the ODB port was connected to the cigarette lighter fuse (which hadn't been working in quite awhile), so after installing the water pump I replaced the fuse and the port was working again. My scanner came back with 2 codes... I forget what they were but the first one was a bad ECT sensor. I replaced that and it helped a little bit... Instead of overheating in 4 minutes, it now takes about 6 minutes. Replacing the sensor cleared both codes though (whatever the 2nd one was).
I'm running out of ideas here (and money)... and was hoping someone had any thoughts?
Just some more random info that may or may not be of use...
- I have been trying to burp the system after adding coolant (several times a day), even though its a pressurized system and doesn't require burping.
- Anytime I say "coolant" I'm referring to water. I've only been putting water in until I solve this, then I'll go back to Dex-Cool.
- There's no coolant leak, but I do lose coolant when it overheats. The mechanic said it's it's an aluminum rad with plastic end caps which act as a pressure release so when it gets too hot, the pressure (and coolant) are ejected from there.
- My rad has no rad cap and no petcock
- Since all this started... my truck now chokes a bit trying to start up... but aside from the choking, she sill starts fairly easily.
- When it starts, there's a puff off white or greyish smoke that comes out the exhaust.
- Since this started, the truck now rides pretty rough if I exceed 70kmh
Thank you all for reading and for any input yous may have.