Overheating Problem w/ NO CODES
April 6th, 2019, 8:59 AM
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Overheating Problem w/ NO CODES
Back in November, I received a 2004 Trailblazer LS as a work vehicle. When I got it, the AC control was broken so I ordered a new one. I previously drove it for around 3 weeks prior to this without any problem. I installed the new AC control and the car overheated for the first time. I've pretty much exhausted all options on this problem. Here are a list of my replacement installs:
2 Radiators
3 Radiator Caps
Radiator Hose (both to the overflow and to the engine)
New Overflow tank
New Fan Clutch
I've installed two, 8 in electric fans on the AC condensor
Water Pump
2 Thermostats (I know the one installed works, I boiled it)
I've also added 2 different type of Head Gasket Sealer over the past 6 months (the first was liquid aluminum *i think* and the second was Blue Devil) I completely flushed the radiator for the Blue Devil, did the directions exactly, but I'm afraid it's already messed up again cause it won't stop overheating.
I can't remember if there are any other things at this moment. Anyway, the car only lists one code (the ABS C0040 - Right Front Speed Sensor Circuit) I seem to have narrowed the problem down to the Fan Clutch (even though it's new), so upon reading another thread I removed the factory harness and wired the 5 wires together. This seems to help in some sense, as the fan would engage at a high speed on a COLD start. However, when the car would overheat, the fan would either not be running, or would be running on what seemed to be a slow speed (before wiring direct I could stop the fan with my fan, now I can't, but it's still running slow and when I cut the ignition the fan immediately stops spinning. I've been told the wire the fan to a switch in my dash so it would run on high at all times, but I've failed every time I've tried to make that work. I can't get it to power on with a switch.
Also, I have switched the relays in the fuse box to ensure they are good and I've attempted to manually turn on my fan by running a 10 amp jumper between 4 and 2 on the relay.
I'm definitely at a lose here on what could be causing the problem due to the fact no codes are showing. ANY help would be appreciated.
2 Radiators
3 Radiator Caps
Radiator Hose (both to the overflow and to the engine)
New Overflow tank
New Fan Clutch
I've installed two, 8 in electric fans on the AC condensor
Water Pump
2 Thermostats (I know the one installed works, I boiled it)
I've also added 2 different type of Head Gasket Sealer over the past 6 months (the first was liquid aluminum *i think* and the second was Blue Devil) I completely flushed the radiator for the Blue Devil, did the directions exactly, but I'm afraid it's already messed up again cause it won't stop overheating.
I can't remember if there are any other things at this moment. Anyway, the car only lists one code (the ABS C0040 - Right Front Speed Sensor Circuit) I seem to have narrowed the problem down to the Fan Clutch (even though it's new), so upon reading another thread I removed the factory harness and wired the 5 wires together. This seems to help in some sense, as the fan would engage at a high speed on a COLD start. However, when the car would overheat, the fan would either not be running, or would be running on what seemed to be a slow speed (before wiring direct I could stop the fan with my fan, now I can't, but it's still running slow and when I cut the ignition the fan immediately stops spinning. I've been told the wire the fan to a switch in my dash so it would run on high at all times, but I've failed every time I've tried to make that work. I can't get it to power on with a switch.
Also, I have switched the relays in the fuse box to ensure they are good and I've attempted to manually turn on my fan by running a 10 amp jumper between 4 and 2 on the relay.
I'm definitely at a lose here on what could be causing the problem due to the fact no codes are showing. ANY help would be appreciated.
April 7th, 2019, 11:58 AM
#2
hvac controls have no control over the fan. if its a fan clutch its mechanical, if its electric...its pcm controlled.
head gasket sealer is snake oil...complete waste...it will fix nothing.
if you put a new rad, waterpump, thermostat, fans and the fans come on when it gets hot....and it and it still overheats...i'm thinking headgasket. any white smoke out the tailpipe?
to test:
-you could put a cooling system pressure gauge on the rad and see if it is developing pressure...if it pressurizes over the cap rating fast after start up...bad
-compression test
-test for presence of combustion gases in coolant with chemical tester.
head gasket sealer is snake oil...complete waste...it will fix nothing.
if you put a new rad, waterpump, thermostat, fans and the fans come on when it gets hot....and it and it still overheats...i'm thinking headgasket. any white smoke out the tailpipe?
to test:
-you could put a cooling system pressure gauge on the rad and see if it is developing pressure...if it pressurizes over the cap rating fast after start up...bad
-compression test
-test for presence of combustion gases in coolant with chemical tester.
April 7th, 2019, 2:25 PM
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Yeah, I know the AC control doesn't have any effect. I just meant that I believe the heat was locked in the ON position on the broken control unit and that's why it wasn't overheating until I changed it out. It's an electric fan clutch and I believe that the PCM isn't correctly telling it when to come on, or actually what speed to run at. However, I'm not getting any codes for it. That's why I'm wanting to actually run a dash switch to manually run it on high whenever I'm driving. Also, I've used gasket sealer in the past and it's definitely worked for me. I'm running a '97 Tahoe for about the past 6 years on it. Regardless, that's not the main issue I'm having, I don't believe. But I appreciate the help. I'm going to put a test on it asap. Thanks again.
April 7th, 2019, 3:10 PM
#4
electric fans don't have a clutch.
there is a reason why professionals don't use head gasket in a can or ANY leak seal product for p/s, a/c or cooling systems. the main consumer are backyarders. I would only use it on a vehicle I Hated.
once you hit highway speed there is enough air to flow thru the rad to cool the engine...the fan has little effect over 40mph. if the issue is happening at highway speed...its not fan related.
if the issue only occurs stopped or stop ang go traffic...an electric fan will have relay; jumper the relay and the fan will run continuously. if that fixes your problem...you can decide if you want to fix it right or jimmy rig a switch. if you must use a switch...don't power the fan directly off a switch...use a relay. switches are not made to handle high current loads.
there is a reason why professionals don't use head gasket in a can or ANY leak seal product for p/s, a/c or cooling systems. the main consumer are backyarders. I would only use it on a vehicle I Hated.
once you hit highway speed there is enough air to flow thru the rad to cool the engine...the fan has little effect over 40mph. if the issue is happening at highway speed...its not fan related.
if the issue only occurs stopped or stop ang go traffic...an electric fan will have relay; jumper the relay and the fan will run continuously. if that fixes your problem...you can decide if you want to fix it right or jimmy rig a switch. if you must use a switch...don't power the fan directly off a switch...use a relay. switches are not made to handle high current loads.