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Is it time for a coolant flush?

13K views 36 replies 8 participants last post by  iwant2buyaGTO 
#1 · (Edited)
Hello. I noticed my coolant to be a little low. Its just below the cold fill line. I haven't seen a recent post about coolant on here so im asking if i should just add some Dex-Cool to it? Or do i need to do a flush? its been at least 2 years since i haven't touched it. Thanks again

04 Pontiac GTO
35,000 miles

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#2 ·
According to the manual, it's every 5 years or 150,000 miles; whichever comes first.
 
#5 ·
The 50/50 is already diluted with water. The regular Dexcool is full strength and need to be mixed with water. I've always thought that the 50/50 was a rip-off.....
 
#6 ·
You late model GTO guys still run that Dex Cool? In the "GTP World" that **** is always flushed out and replaced with conventional "green" antifreeze. Dex Cool causes all kinds of problems with clogging the cooling system and tearing up seals on the intake manifold. Just curious.
 
#10 ·
Not true.
Clogging: Many think the sludge in the overfill is a breakdown of DEXCOOL when in fact its a rust inhibitor placed in there at factory to prevent corrosion, and to keep the internal workings of the water pump etc lubricated.

Many panic and say OMG the coolant has broken down. They flush this additive all out and replace with conventional anti-freeze. After a while things start happening to their radiator and other parts associated with cooling. Many come in here seeking answers to why did my radiator blow? Why did this happen? You ask them did you replace the DEXCOOL? The common denominator to most answers are: YES my radiator had sludge in it from the DEXCOOL and I replaced with conventional Anti-Freeze.

The owners manual clearly states use ONLY DEXCOOL. My 2004 Grand-AM says use only DEXCOOL.... My 2007 Doge RAM says use only: MOPARS version of DEXCOOL.

Little ironic its the GTOS using this new formatted coolant that has all these issues isn't it?

Many are ignorant of the proper additives for this car, from DEXCOOL to synthetic oils to F.M. in the rear end.

The only issues I see are from those who are not properly maintaining these cars. MOSTLY 2-4th owners of the car.

Tearing up seals? These motors are designed to be using DEXCOOL. Maybe the seals some are reporting being torn up is being done so by improper coolants or other factors.

Many know it alls on these cars who post their authorivite knowledge on them turn out to be shall I say less than astute on them.

USE DEXCOOL ONLY.... on this new GTO....

My '70 or older cars? NO!

Whenever in doubt ...... read the friggin manual. :rolleyes:
 
#11 ·
Hello. I noticed my coolant to be a little low. Its just below the cold fill line. I haven't seen a recent post about coolant on here so im asking if i should just add some Dex-Cool to it? Or do i need to do a flush? its been at least 2 years since i haven't touched it. Thanks again

04 Pontiac GTO
35,000 miles

View attachment 15637
If there is DEXCOOL in it and judging by the pic it is........ top it off with a 50/50 mix of distilled water and DEXCOOL.

Buy a gallon of DEXCOOL and a gallon of distilled water. Mix it 50/50. it will net you 2 gallons. Why buy a 50/50 mix for more than gallon of straight? 14.00 gets ya 2 gallons.

You should not need to flush it at 35K miles. Car used? You have no idea what was done to it.

NEVER EVER EVER EVER under any circumstances mix DEXCOOL and anti-freeze. The chemical reaction will cause the issues many complain about and blame it on DEXCOOL.
 
#18 ·
Yes im pretty sure its dex-cool. So you think i should just top it off? I was concerned it needed a flush by now. I just emailed the previous owner and asked if they did a radiator flush on it. I should hear from them soon.
 
#12 ·
ONLY use Dexcool in the GTO. Personally, I'd do it more often then the owners manual says to for the simple fact its cheap. Also, as Judge said... that sluge is actually there for a reason. I wouldn't flush it but I would drain it and refil.

Don't buy the 50/50. Its only $2 more for the non pre-mixed and it does 2X the amount. Much cheaper in the long run.

I also just used tap water. Never had an issue with any car from it.

And for those OCD people with maintance like myself, I'd do the t-stat just because its only $20 while I have access to it.
 
#13 ·
Dunno where you live but here our water is extremely hard. Extreme calcium build up the water while drinkable contains that much chlorine you can smell it and taste it at times.
Putting water from my tap in the radiator the calcium in it that hardens on walls stubs and the spots it leaves on cars.... for 89 cents..... distilled water is a better solution.
 
#15 ·
I made a huge mess when I did mine LOL. I was pissed that my t-stat got stuck open in winter and I had no heat. Didn't help that it was 30*, dark, and I was rushing to get it done after work.

Probally could of took my time and did a cleaner job though. The LS2 guys are lucky.

And you guys are right... I probally should spring the $1 for water.
 
#16 ·
I'll add an addendum to my earlier 'tap water' statement. For about the last 15 years or so I've used filtered tap water but, none the less, tap water.
 
#22 ·
From the service manual:
Cooling System Draining and Filling

Draining Procedure

Caution: With a pressurized cooling system, the coolant temperature in the radiator can be considerably higher than the boiling point of the solution at atmospheric pressure. Removal of the surge tank cap, while the cooling system is hot and under high pressure, causes the solution to boil instantaneously with explosive force. This will cause the solution to spew out over the engine, the fenders, and the person removing the cap. Serious bodily injury may result.

•Park the vehicle on a level surface.
•Remove the coolant pressure cap.
•Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
•Place a drain pan under the lower radiator hose.
•Remove the lower radiator hose from the radiator.
•Drain the cooling system.
•Inspect the coolant.
•Follow the appropriate procedure based on the condition of the coolant.
• Normal in appearance--follow the filling procedure.

• Discolored--follow the flush procedure. Refer to Manufactures instructions.

Filling Procedure

•Connect the lower radiator hose.
•Lower the vehicle.
Important: Use a 50/50 mixture of DEX-COOL antifreeze and deionized water.

•Slowly fill the cooling system through the upper radiator hose with a 50/50 coolant mixture until the coolant comes out the coolant air bleed hose.
•Fill the radiator with coolant through the surge tank opening to the full line.
•Install the coolant pressure cap.
•Start the engine.
•Run the engine at 2,000-2,500 RPM until the engine reaches normal operating temperature.
•Allow the engine to idle for 3 minutes.
•Shut the engine OFF.
•Allow the engine to cool.
•Top off the coolant as necessary.
•Inspect the concentration of the engine coolant.
•Rinse away any excess coolant from the engine and the engine compartment.
•Inspect the cooling system for leaks.
 
#30 ·
Your making this much harder then it needs to be and stressful over $20 in coolant. Just drain the system and put some fresh in and move on.
 
#35 ·
As stated earlier:
Your making this much harder then it needs to be and stressful over $20 in coolant. Just drain the system and put some fresh in and move on.
The capacity is 15.1 qts. for a 2004 according to the manual and everything you need to know is in post #22.
 
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