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Discussion Starter · #1 ·
I bought this truck roughly a year ago and it's recently been giving me some issues. No check engine light but starts getting warm when sitting still when driving is fine it has a new radiator and cap put in when bought and the system was flushed about 50 times due to the stop leak I could see in it. My first thought is electric fan clutch wanting some other opinions. This issue presented itself at the same time as my ac issue. Was on a trip out of town and the ac just stopped blowing cold seen the clutch wasn't engaged hooked up guages and found it was overcharged. I corrected the charge issue and clutch works as expected but now I don't have cold or even cool air crazy thing is it was working well and blowing very cold when it was way over charged.... thoughts?
 

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Seems like it really wasn't overcharged.

I bet your idle airflow through the core (radiator and condenser) hurts a lot and you may think it's OK when it isn't.

AC will read overpressure when it cannot get the heat out through the condenser ... but it will run pretty well at speeds over 40 or so - that's called "Ram Air" and your fan is of ZERO help once the vehicle is going that fast.

So if the system is reading the ambient and the engine coolant temp correctly, the fan will go into "coast-mode" and although it spins, that's just from road speed air hitting it.

Don't put another fan on it - fix it to the way it was built - which could actively compensate for most any circumstance.
 

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Discussion Starter · #3 ·
Seems like it really wasn't overcharged.

I bet your idle airflow through the core (radiator and condenser) hurts a lot and you may think it's OK when it isn't.

AC will read overpressure when it cannot get the heat out through the condenser ... but it will run pretty well at speeds over 40 or so - that's called "Ram Air" and your fan is of ZERO help once the vehicle is going that fast.

So if the system is reading the ambient and the engine coolant temp correctly, the fan will go into "coast-mode" and although it spins, that's just from road speed air hitting it.

Don't put another fan on it - fix it to the way it was built - which could actively compensate for most any circumstance.
Fix it how?
 

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Are you any sort of mechanic?

High head pressure... if it's not from overcharge, is from superheating and you were foolish to dump the freon because that was a result, not the cause of your trouble.

Fix the problem, not the result.

10-98
 

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Discussion Starter · #6 ·
Are you any sort of mechanic?

High head pressure... if it's not from overcharge, is from superheating and you were foolish to dump the freon because that was a result, not the cause of your trouble.

Fix the problem, not the result.

10-98
I am very mechanically inclined and can do most of my own work I know how to read the guages and the range they need to be in but I'm not a mechanic and other than pulling a vacuum and reading guages and charging is the extent of my knowledge on ac so what would you suggest is my problem?
 

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Do some visual checks first. Make sure the fans working properly, the car isn't overheating, etc. You should hear the fan speed up and slow down with the a/c on. Look for anything on the condenser blocking it, like excessive bugs.
Hook up a Tech 2 and read the a/c numbers. The Tech 2 will read the high pressure switch and various other components in the a/c, make sure they are within range. You can test the low pressure switch by jumping it and seeing if the compressor engages.
Drain the freon, get a new orifice tube and install it. Check for debris on the tube, if there is, you have to find what's bad, probably a compressor. Replace the tube, vacuum the system down to 30" for 1/2 to 1 hour. Turn off the valves and make sure it holds that vacuum for about 10-20 minutes. If not, there's a leak. Then re charge with the proper amount of 134a. The amount of freon is on a label under the hood.
If the cars been sitting out in the sun on a 100 degree day, yes, the pressures will seem excessive.
 

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Discussion Starter · #8 ·
Do some visual checks first. Make sure the fans working properly, the car isn't overheating, etc. You should hear the fan speed up and slow down with the a/c on. Look for anything on the condenser blocking it, like excessive bugs.
Hook up a Tech 2 and read the a/c numbers. The Tech 2 will read the high pressure switch and various other components in the a/c, make sure they are within range. You can test the low pressure switch by jumping it and seeing if the compressor engages.
Drain the freon, get a new orifice tube and install it. Check for debris on the tube, if there is, you have to find what's bad, probably a compressor. Replace the tube, vacuum the system down to 30" for 1/2 to 1 hour. Turn off the valves and make sure it holds that vacuum for about 10-20 minutes. If not, there's a leak. Then re charge with the proper amount of 134a. The amount of freon is on a label under the hood.
If the cars been sitting out in the sun on a 100 degree day, yes, the pressures will seem excessive.
Ok the entire ac system was replaced new a year ago so I hope it's not a compressor where is the orifice tube. And I had dye put in when charged and haven't found any leaks. I don't hear the fan go faster at any point. At idle not moving is when it starts getting warm and then when the message pops up engine coolant hot or something like that I hear the engine idle up as if trying to kick the fan up to high but I hear no change in the fan. At my dad's shop we have a snap on computer that can read everything but I don't know what things I need to check and how to read some of the information it gives. My dad does but he's hardly ever there to teach me so I have learned a lot of the basics like code reading and automatic tests but that's about it.
 

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Discussion Starter · #9 ·
This thing is a 4.2 with over 300k miles on it and it's still strong it was extensively serviced and only has had ac Delco replacement parts on it. I bought this car at a good deal from a friend knowing i had to replace transmission & radiator. Since then it's been great I did new plugs a week ago and didn't know the whole story about using ac Delco until I found this website so when I get this other issue fixed I'll go back and put Delco plugs in. Anyways seems to me like my ac problem is stemming from lack of air flow through the condenser which is causing lack of airflow through the radiator and causing the engine to get warm when not moving? And that in turn is what caused my high ac pressure is what I'm drawing from this? So I check the condenser and radiator for obstructions if so clear them and check the orifice tube for any signs of debris or damage and replace. Then if orifice is clear do I still replace it? Then recharge? And last thing the difference between prices on electric fan clutch if that's an issue are huge in difference and right now I can only afford a cheap one off Amazon if that ends up being my issue because we have a baby coming in 2 days and I need to make sure I get this fixed so I don't have a newborn in this heat with no ac. Sorry for all the questions I just want to be thorough as I can at once so I'm not missing something it could be.
 

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Congratulations on your baby, best of luck.
On my 04 TB, the windshield washer tank needs to be removed, there's an aluminum line behind it. The orifice tube is in the line, there's 2 small dents in the line to keep it in place. Disconnect the fitting (drain the system first), reach in with a pair of needlenose pliers and pull it out. Theres a tool for it, I've never needed it.
If there's a metal shard or 2 on it, it's ok. Any more than that, start looking at components, compressor most likely. If it's covered in goop, the dessicant bag in the accumulator broke. The orifice tube is cheap, $5-10. Make sure the arrow on it points toward the accumulator. Look for the arrow when you take it out.
For the fan clutch, when the cars warmed up, try stopping it with a rag, being VERY careful. No resistance, you need one. Search on this site for the best ones to buy.
The fan should speed up every once in a while with the a/c on. You'll hear it. It may not be doing it because the a/c isn't working properly, the compressor clutch has to be cycling.
You mentioned that there were several a/c components replaced, was the proper amount of oil added to each component?
And yes, I'm saying lack of air flow MAY be the problem, although getting up to highway speed should help, even if the fan clutch is bad.
If your dads not at the shop much, maybe on of the other guys there will help you out?
 

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Discussion Starter · #11 ·
Well it's
Congratulations on your baby, best of luck.
On my 04 TB, the windshield washer tank needs to be removed, there's an aluminum line behind it. The orifice tube is in the line, there's 2 small dents in the line to keep it in place. Disconnect the fitting (drain the system first), reach in with a pair of needlenose pliers and pull it out. Theres a tool for it, I've never needed it.
If there's a metal shard or 2 on it, it's ok. Any more than that, start looking at components, compressor most likely. If it's covered in goop, the dessicant bag in the accumulator broke. The orifice tube is cheap, $5-10. Make sure the arrow on it points toward the accumulator. Look for the arrow when you take it out.
For the fan clutch, when the cars warmed up, try stopping it with a rag, being VERY careful. No resistance, you need one. Search on this site for the best ones to buy.
The fan should speed up every once in a while with the a/c on. You'll hear it. It may not be doing it because the a/c isn't working properly, the compressor clutch has to be cycling.
You mentioned that there were several a/c components replaced, was the proper amount of oil added to each component?
And yes, I'm saying lack of air flow MAY be the problem, although getting up to highway speed should help, even if the fan clutch is bad.
If your dads not at the shop much, maybe on of the other guys there will help you out?
Well it's a wrecker service that my dad owns he uses the computer for his trucks but it's not a repair shop but anything I need to do I can do there. All the ac work was done at the dealer before I bought the car but he gave me a folder of all the service work done he had absolutely everything done at the dealer down to headlight bulbs. I can check the resistance on the fan when I check everything out at speed it doesn't get warm at all stays right at 210. Ac clutch was working fine when I had the guages hooked up. It was cycling in correct ranges and it was blowing cold sitting still in the parking lot as soon as I started driving it shut off and hasn't been back on since. So I think I have a mixture of problems and I'll get back with you after I check all the things we discussed.
 

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How is the tension on the serpentine belt? If it's slipping a bit it may not be turning the water pump properly at low speeds, or the pump itself may have worn vanes which means it must be replaced. You haven't mixed coolant types, I hope. Topping up a Dex-Cool system with the green stuff is a recipe for disaster, as the Dex-Cool will turn to sludge in the engine. The only way to get that out is to have the block hot tanked, an expensive hobby.
The engine getting too warm at low speeds/idle but cooling at high speed really sounds to me like a water pump issue. I would check the belt tension first, though. It could be a bad belt tensioner. You aren't having any other issues with any belt driven components, are you?
 
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