Overheating Issue - Within 5 Minutes of Driving
#1
05-19-2017, 11:56 PM
Overheating Issue - Within 5 Minutes of Driving
I have a 2003 4WD 4.6L Blazer and I have a couple issues I wanted to get some advice on before proceeding.
I was getting the following error codes earlier this week:
P0440 Evaporative Emission Control System Malfunction
P0420 Catalyst System Efficiency Below Threshold
Symptoms of my vehicle:
- Low power to acceleration (revs over 4,000 RPMs to get past 35mph)
- Sluggish start, turning over the key once or twice
- I turned on the heater to help the overheating problem, I have no heat coming through - it's just cold air
- New Problem: Overheating - going from cold engine to 260 within 5 minutes of running the Blazer. Keep in mind, I'm not loosing coolant (except the stuff burning off from overheating) and my lower radiator hose is cold and my upper radiator hose is extremely hot to the touch.
What I have done:
- Did OBD-II emissions reading, all O2 sensors were OK and functioning.
- Replaced catalytic converter, the OBD-II reading said it was functioning at 300 degrees so it needed to be replaced anyway.
- Ran Cataclean through my truck before replacing the catalytic converter (I was waiting for the part and needed a Band-Aid - I was in a serious bind!)
- Tried adding Redline Water Wetter in my radiator reservoir - still went from cold to 260 within 5 minutes of regular driving.
Now what??
With the engine overheating and I still have loss of power when accelerating, I have no idea what is going on with my Blazer. Keep in mind that the lower radiator hose is cool to the touch while the upper is blazing hot after 5 minutes of driving. Continued loss of power - that's another concern probably tied to the overheating (I'm guessing here).
Help! I don't know what else to do and I am at a loss.
I was getting the following error codes earlier this week:
P0440 Evaporative Emission Control System Malfunction
P0420 Catalyst System Efficiency Below Threshold
Symptoms of my vehicle:
- Low power to acceleration (revs over 4,000 RPMs to get past 35mph)
- Sluggish start, turning over the key once or twice
- I turned on the heater to help the overheating problem, I have no heat coming through - it's just cold air
- New Problem: Overheating - going from cold engine to 260 within 5 minutes of running the Blazer. Keep in mind, I'm not loosing coolant (except the stuff burning off from overheating) and my lower radiator hose is cold and my upper radiator hose is extremely hot to the touch.
What I have done:
- Did OBD-II emissions reading, all O2 sensors were OK and functioning.
- Replaced catalytic converter, the OBD-II reading said it was functioning at 300 degrees so it needed to be replaced anyway.
- Ran Cataclean through my truck before replacing the catalytic converter (I was waiting for the part and needed a Band-Aid - I was in a serious bind!)
- Tried adding Redline Water Wetter in my radiator reservoir - still went from cold to 260 within 5 minutes of regular driving.
Now what??
With the engine overheating and I still have loss of power when accelerating, I have no idea what is going on with my Blazer. Keep in mind that the lower radiator hose is cool to the touch while the upper is blazing hot after 5 minutes of driving. Continued loss of power - that's another concern probably tied to the overheating (I'm guessing here).
Help! I don't know what else to do and I am at a loss.
Last edited by run_girl; 05-20-2017 at 12:01 AM.
#2
05-20-2017, 02:07 AM
Bad thermostat or a clog in the cooling system.. possibly both. If it's overheating don't drive it, you run the chance of ruining your motor.
Any noticeable leaking coolant? Check the coolant level at the radiator as well. Should be able to see coolant with the cap off.
Also, your motor is a 4.3.
Any noticeable leaking coolant? Check the coolant level at the radiator as well. Should be able to see coolant with the cap off.
Also, your motor is a 4.3.
Last edited by Private_Ops; 05-20-2017 at 02:15 AM.
#3
05-20-2017, 07:07 AM
Very sound advice from Private Ops. Meanwhile, how many miles do you have on the vehicle? High(er) mileage vehicles (100K+) will often begin to experience clogged radiator issues. And is there any chance that someone added non-Dexcool antifreeze to the cooling system? Doing so can cause serious cooling system blockage issues (which could explain your 'no heat' from the heater symptom).
#4
05-20-2017, 07:18 AM
Very sound advice from Private Ops. Meanwhile, how many miles do you have on the vehicle? High(er) mileage vehicles (100K+) will often begin to experience clogged radiator issues. And is there any chance that someone added non-Dexcool antifreeze to the cooling system? Doing so can cause serious cooling system blockage issues (which could explain your 'no heat' from the heater symptom).
I have 155K miles on my Blazer. I've only used Dexcool as my antifreeze, so at least we can rule out that issue (maybe?). I flushed the radiator last October and put Dexcool back - and burped it then.
I read the Chilton repair manual and it said that when the upper hose is hot and lower is cool that it may not be the thermostat. Do you all think that's wrong?
#5
05-20-2017, 07:21 AM
Bad thermostat or a clog in the cooling system.. possibly both. If it's overheating don't drive it, you run the chance of ruining your motor.
Any noticeable leaking coolant? Check the coolant level at the radiator as well. Should be able to see coolant with the cap off.
Also, your motor is a 4.3.
Any noticeable leaking coolant? Check the coolant level at the radiator as well. Should be able to see coolant with the cap off.
Also, your motor is a 4.3.
I should mention too - NO white exhaust (so I'm ruling out the head gasket at this point).
#7
05-20-2017, 08:10 AM
OK 👍 thanks! Do you all believe that it is the thermostat? They are only $20 - easy fix. Would that explain the no heat issue as well. Sorry, pulling out my girl card on this one because I don't want to keep pouring money into every plausible issue. Plus, Uber rides to work are getting pricey!
#8
05-20-2017, 12:14 PM
Water pump could also be culprit... it's hard to diagnose without actually seeing it in person.
Thermostat is a quick easy (cheap) check. Make sure your coolant level is topped off at the radiator (over flow tank is for expansion).
Thermostat is a quick easy (cheap) check. Make sure your coolant level is topped off at the radiator (over flow tank is for expansion).
#9
05-20-2017, 04:57 PM
Start with the thermostat as others mentioned; that's a quick and easy job.
My diagnosis, clogged radiator and/or weak water pump. The fact that the top hose is getting hot and the lower is remaining cold sounds like the thermostat is working like it should, but again it's a quick and easy job, so if you're going to have the cooling system open for any maintenance, it's not a bad thing to consider replacing.
How's does the coolant in the system actually look? Should be transparent orange. The older it gets, the darker and less transparent it tends to get. Gets even darker if it starts getting contaminated from deposits building in the system. From what I've seen, the best and quickest check of the coolant in these trucks is to just pop the radiator cap (when the engine is cool obviously...) Since the cap has the pressure valve on it that feeds to the overfill bottle, water is forced pass the rubber seal on it and it tends to collect the contaminates in the process. If you pop the cap off and it has a lot of gritty looking bits or even a mud-type consistency around the cap, then you can almost bet that same deposit is in the heater core, radiator, thermostat, water pump, etc...
This often happens with some off the shelf full strength Dex Cool antifreeze if tap water is used to dilute it instead of distilled water which is what most say to use with them. Distilled water is cheap and it honestly doesn't take much to put in the system to dilute the Dex Cool down you're adding so it's the right thing to do. Or, just get pre-mixed stuff, that's even easier, although your money usually goes further with the full strength.
If it's got a lot of gunk in it, you can TRY and flush the system. The easiest but not the most throughout is to just pull the upper radiator hose off at the radiator and the lower radiator hose off at the water pump, then you can try and run clean water through the radiator with a garden hose from the top hose opening and letting it run out of the lower hose until it runs clear. Unless you have some crazy high water pressure at your house... the radiator should allow you to run the water through it at near, if not full speed without restriction, and flow through it and out the lower hose. If if doesn't flow much and just backs up and comes out of the upper hose inlet where you're putting water in, your first step needs to be to replace the radiator, because the cores inside are clogged... I've personally never been able to successfully flush and clean a radiator once it's gotten to that point, I've just replaced it...
If the radiator flows fine, then I'd start looking at a water pump replacement. Not a hard job at all on the 4.3l if you're at all mechanically inclined. I just changed mine yesterday actually :P Especially if there's contaminates, although there's corrosion inhibitors in antifreeze to stop this from happening, the fins on the impeller will sometimes corrode away slowly and cause the pump to become less efficient over time, but I've only ever seen this on OOOOOLD water pumps; ones that should have replaced a LOOOONG time ago lol but it does happen.
After all you get the engine to not overheat anymore and you still don't have a working heater inside, you can attempt to flush the heater core to get the heat working again, but do so at your own risk... To do this, just remove the two heater hoses running to the heater core on the firewall from the intake side and flush water through them in both directions until you get nothing but clean water coming back out (same concept as flushing the radiator). You may have success and the heater will start blowing warm air again, and for some people they never have another issue with it again after that. But maybe 75% of the time, the heater core will start leaking soon afterwards... Then you're either bypassing your heater core and you're back to not having a heater, or ripping into your dash and replacing the leaking heater core... I flushed the core on my 04 a couple years back when I replaced the water pump and radiator, heat was working although not very well. I did get a little junk out, and the heater works great to this day and have never had an issue since. Rewind back about 10 years ago when I had a 91 Toyota Pickup, I flushed the core on it because the heater was getting very weak. Heat worked AWESOME for about 2 weeks because I starter getting an antifreeze "mist" coming from the dash vents while going down the road... talk about choking you out of a vehicle... So of the two heater cores I've ever flush on my personal vehicles, I've had a 50% success rate lol.
My diagnosis, clogged radiator and/or weak water pump. The fact that the top hose is getting hot and the lower is remaining cold sounds like the thermostat is working like it should, but again it's a quick and easy job, so if you're going to have the cooling system open for any maintenance, it's not a bad thing to consider replacing.
How's does the coolant in the system actually look? Should be transparent orange. The older it gets, the darker and less transparent it tends to get. Gets even darker if it starts getting contaminated from deposits building in the system. From what I've seen, the best and quickest check of the coolant in these trucks is to just pop the radiator cap (when the engine is cool obviously...) Since the cap has the pressure valve on it that feeds to the overfill bottle, water is forced pass the rubber seal on it and it tends to collect the contaminates in the process. If you pop the cap off and it has a lot of gritty looking bits or even a mud-type consistency around the cap, then you can almost bet that same deposit is in the heater core, radiator, thermostat, water pump, etc...
This often happens with some off the shelf full strength Dex Cool antifreeze if tap water is used to dilute it instead of distilled water which is what most say to use with them. Distilled water is cheap and it honestly doesn't take much to put in the system to dilute the Dex Cool down you're adding so it's the right thing to do. Or, just get pre-mixed stuff, that's even easier, although your money usually goes further with the full strength.
If it's got a lot of gunk in it, you can TRY and flush the system. The easiest but not the most throughout is to just pull the upper radiator hose off at the radiator and the lower radiator hose off at the water pump, then you can try and run clean water through the radiator with a garden hose from the top hose opening and letting it run out of the lower hose until it runs clear. Unless you have some crazy high water pressure at your house... the radiator should allow you to run the water through it at near, if not full speed without restriction, and flow through it and out the lower hose. If if doesn't flow much and just backs up and comes out of the upper hose inlet where you're putting water in, your first step needs to be to replace the radiator, because the cores inside are clogged... I've personally never been able to successfully flush and clean a radiator once it's gotten to that point, I've just replaced it...
If the radiator flows fine, then I'd start looking at a water pump replacement. Not a hard job at all on the 4.3l if you're at all mechanically inclined. I just changed mine yesterday actually :P Especially if there's contaminates, although there's corrosion inhibitors in antifreeze to stop this from happening, the fins on the impeller will sometimes corrode away slowly and cause the pump to become less efficient over time, but I've only ever seen this on OOOOOLD water pumps; ones that should have replaced a LOOOONG time ago lol but it does happen.
After all you get the engine to not overheat anymore and you still don't have a working heater inside, you can attempt to flush the heater core to get the heat working again, but do so at your own risk... To do this, just remove the two heater hoses running to the heater core on the firewall from the intake side and flush water through them in both directions until you get nothing but clean water coming back out (same concept as flushing the radiator). You may have success and the heater will start blowing warm air again, and for some people they never have another issue with it again after that. But maybe 75% of the time, the heater core will start leaking soon afterwards... Then you're either bypassing your heater core and you're back to not having a heater, or ripping into your dash and replacing the leaking heater core... I flushed the core on my 04 a couple years back when I replaced the water pump and radiator, heat was working although not very well. I did get a little junk out, and the heater works great to this day and have never had an issue since. Rewind back about 10 years ago when I had a 91 Toyota Pickup, I flushed the core on it because the heater was getting very weak. Heat worked AWESOME for about 2 weeks because I starter getting an antifreeze "mist" coming from the dash vents while going down the road... talk about choking you out of a vehicle... So of the two heater cores I've ever flush on my personal vehicles, I've had a 50% success rate lol.
Last edited by blazen_red_4x4; 05-20-2017 at 05:08 PM.
#10
05-23-2017, 02:47 AM
Great Stuff!
OK, this is what I have done and I continue to have overheating, and no heat coming out of my Blazer. I also have low power when accelerating - like it still revs beyone 4,000rpms to get past 35mph. I no longer have error codes from my OBD-2 reading either.
So my question is What the heck is wrong with my truck?!? I refuse to think it's a blown head gasket because that would just make me break down into tears.
OK, this is what I have done and I continue to have overheating, and no heat coming out of my Blazer. I also have low power when accelerating - like it still revs beyone 4,000rpms to get past 35mph. I no longer have error codes from my OBD-2 reading either.
- Replaced the catalytic converter
- Replaced the thermostat
- Replaced the water pump - not a fun job at all!
So my question is What the heck is wrong with my truck?!? I refuse to think it's a blown head gasket because that would just make me break down into tears.
Start with the thermostat as others mentioned; that's a quick and easy job.
My diagnosis, clogged radiator and/or weak water pump. The fact that the top hose is getting hot and the lower is remaining cold sounds like the thermostat is working like it should, but again it's a quick and easy job, so if you're going to have the cooling system open for any maintenance, it's not a bad thing to consider replacing.
How's does the coolant in the system actually look? Should be transparent orange. The older it gets, the darker and less transparent it tends to get. Gets even darker if it starts getting contaminated from deposits building in the system. From what I've seen, the best and quickest check of the coolant in these trucks is to just pop the radiator cap (when the engine is cool obviously...) Since the cap has the pressure valve on it that feeds to the overfill bottle, water is forced pass the rubber seal on it and it tends to collect the contaminates in the process. If you pop the cap off and it has a lot of gritty looking bits or even a mud-type consistency around the cap, then you can almost bet that same deposit is in the heater core, radiator, thermostat, water pump, etc...
This often happens with some off the shelf full strength Dex Cool antifreeze if tap water is used to dilute it instead of distilled water which is what most say to use with them. Distilled water is cheap and it honestly doesn't take much to put in the system to dilute the Dex Cool down you're adding so it's the right thing to do. Or, just get pre-mixed stuff, that's even easier, although your money usually goes further with the full strength.
If it's got a lot of gunk in it, you can TRY and flush the system. The easiest but not the most throughout is to just pull the upper radiator hose off at the radiator and the lower radiator hose off at the water pump, then you can try and run clean water through the radiator with a garden hose from the top hose opening and letting it run out of the lower hose until it runs clear. Unless you have some crazy high water pressure at your house... the radiator should allow you to run the water through it at near, if not full speed without restriction, and flow through it and out the lower hose. If if doesn't flow much and just backs up and comes out of the upper hose inlet where you're putting water in, your first step needs to be to replace the radiator, because the cores inside are clogged... I've personally never been able to successfully flush and clean a radiator once it's gotten to that point, I've just replaced it...
If the radiator flows fine, then I'd start looking at a water pump replacement. Not a hard job at all on the 4.3l if you're at all mechanically inclined. I just changed mine yesterday actually :P Especially if there's contaminates, although there's corrosion inhibitors in antifreeze to stop this from happening, the fins on the impeller will sometimes corrode away slowly and cause the pump to become less efficient over time, but I've only ever seen this on OOOOOLD water pumps; ones that should have replaced a LOOOONG time ago lol but it does happen.
After all you get the engine to not overheat anymore and you still don't have a working heater inside, you can attempt to flush the heater core to get the heat working again, but do so at your own risk... To do this, just remove the two heater hoses running to the heater core on the firewall from the intake side and flush water through them in both directions until you get nothing but clean water coming back out (same concept as flushing the radiator). You may have success and the heater will start blowing warm air again, and for some people they never have another issue with it again after that. But maybe 75% of the time, the heater core will start leaking soon afterwards... Then you're either bypassing your heater core and you're back to not having a heater, or ripping into your dash and replacing the leaking heater core... I flushed the core on my 04 a couple years back when I replaced the water pump and radiator, heat was working although not very well. I did get a little junk out, and the heater works great to this day and have never had an issue since. Rewind back about 10 years ago when I had a 91 Toyota Pickup, I flushed the core on it because the heater was getting very weak. Heat worked AWESOME for about 2 weeks because I starter getting an antifreeze "mist" coming from the dash vents while going down the road... talk about choking you out of a vehicle... So of the two heater cores I've ever flush on my personal vehicles, I've had a 50% success rate lol.
My diagnosis, clogged radiator and/or weak water pump. The fact that the top hose is getting hot and the lower is remaining cold sounds like the thermostat is working like it should, but again it's a quick and easy job, so if you're going to have the cooling system open for any maintenance, it's not a bad thing to consider replacing.
How's does the coolant in the system actually look? Should be transparent orange. The older it gets, the darker and less transparent it tends to get. Gets even darker if it starts getting contaminated from deposits building in the system. From what I've seen, the best and quickest check of the coolant in these trucks is to just pop the radiator cap (when the engine is cool obviously...) Since the cap has the pressure valve on it that feeds to the overfill bottle, water is forced pass the rubber seal on it and it tends to collect the contaminates in the process. If you pop the cap off and it has a lot of gritty looking bits or even a mud-type consistency around the cap, then you can almost bet that same deposit is in the heater core, radiator, thermostat, water pump, etc...
This often happens with some off the shelf full strength Dex Cool antifreeze if tap water is used to dilute it instead of distilled water which is what most say to use with them. Distilled water is cheap and it honestly doesn't take much to put in the system to dilute the Dex Cool down you're adding so it's the right thing to do. Or, just get pre-mixed stuff, that's even easier, although your money usually goes further with the full strength.
If it's got a lot of gunk in it, you can TRY and flush the system. The easiest but not the most throughout is to just pull the upper radiator hose off at the radiator and the lower radiator hose off at the water pump, then you can try and run clean water through the radiator with a garden hose from the top hose opening and letting it run out of the lower hose until it runs clear. Unless you have some crazy high water pressure at your house... the radiator should allow you to run the water through it at near, if not full speed without restriction, and flow through it and out the lower hose. If if doesn't flow much and just backs up and comes out of the upper hose inlet where you're putting water in, your first step needs to be to replace the radiator, because the cores inside are clogged... I've personally never been able to successfully flush and clean a radiator once it's gotten to that point, I've just replaced it...
If the radiator flows fine, then I'd start looking at a water pump replacement. Not a hard job at all on the 4.3l if you're at all mechanically inclined. I just changed mine yesterday actually :P Especially if there's contaminates, although there's corrosion inhibitors in antifreeze to stop this from happening, the fins on the impeller will sometimes corrode away slowly and cause the pump to become less efficient over time, but I've only ever seen this on OOOOOLD water pumps; ones that should have replaced a LOOOONG time ago lol but it does happen.
After all you get the engine to not overheat anymore and you still don't have a working heater inside, you can attempt to flush the heater core to get the heat working again, but do so at your own risk... To do this, just remove the two heater hoses running to the heater core on the firewall from the intake side and flush water through them in both directions until you get nothing but clean water coming back out (same concept as flushing the radiator). You may have success and the heater will start blowing warm air again, and for some people they never have another issue with it again after that. But maybe 75% of the time, the heater core will start leaking soon afterwards... Then you're either bypassing your heater core and you're back to not having a heater, or ripping into your dash and replacing the leaking heater core... I flushed the core on my 04 a couple years back when I replaced the water pump and radiator, heat was working although not very well. I did get a little junk out, and the heater works great to this day and have never had an issue since. Rewind back about 10 years ago when I had a 91 Toyota Pickup, I flushed the core on it because the heater was getting very weak. Heat worked AWESOME for about 2 weeks because I starter getting an antifreeze "mist" coming from the dash vents while going down the road... talk about choking you out of a vehicle... So of the two heater cores I've ever flush on my personal vehicles, I've had a 50% success rate lol.