Best radiator flushing product and tips and tricks

[burbguy82]

I have to take apart a 7.4 Vortec pretty soon. Change the lower intake gasket=pretty big job. Thought about flushing the radiator before changing the gasket and refilling. Any tips or products that you have had any experience with? Thanks.

 

[JHZR2]

What year? Later 7.4 had dexcool and if it was never mixed with other coolants, it will be pristine.

If it did get mixed and has sludge in it, then. Flush and flush some more. Maybe do a citric acid flush.

 

[burbguy82]

citric acid flush

please tell more


it is a 99, dexcool is there, You think it will be clean after 25years? I did buy some more coolant, 4 gallons of Dexcool,

 

[jetman]

I have to take apart a 7.4 Vortec pretty soon. Change the lower intake gasket=pretty big job. Thought about flushing the radiator before changing the gasket and refilling. Any tips or products that you have had any experience with? Thanks.

Use as directed.

 

[Gus_Mahn]

Lots of people swear by dishwasher detergent. Never have tried it myself. I usually just do a drain and fill every year or two.

 

[Nukeman7]

Maybe do a citric acid flush.

please tell more

Here is a good write up on how to perform a citric acid flush of a cooling system.

Citric Acid Flush Procedure w/ Pics

 

[Austinowa]

Yup citric acid flush gets my vote, I bought I think a 4 pound bag off of Amazon for my 1995 dodge Cummins. The radiator had a ton of deposits and I ended up getting impatient with the process and decided to get a gallon of the 20 or 30% vinegar.

Do not use that, I put it in and drained it in 30 minutes but came back next day with a hole in radiator.

Another one that worked really good was the evaporust thermocure, they stopped carrying it at local auto part stores unfortunately.

 

[Johnny248]

Irontite Thoro-Flush seems to work really well. Just follow the instructions.

 

[SHOZ]

Lots of people swear by dishwasher detergent. Never have tried it myself. I usually just do a drain and fill every year or two.

I bet that would be great after a citric acid flush. It would neutralize the acid immediately.

But then I read 'you will never get all the bubbles out'. That Shout gel stain remover looks like some stout stuff.

: SC Johnson

www.whatsinsidescjohnson.com

 

[JHZR2]

please tell more


it is a 99, dexcool is there, You think it will be clean after 25years? I did buy some more coolant, 4 gallons of Dexcool,

My 98 S-10 is spotless. I assume yours has the angled radiator neck, but a metal radiator cap?

Diesel giant citric flush is linked above. That’s the process I’ve used.

Try to snap some photos down the radiator neck. Let’s have a look!

 

[nthach]

GM wants a strong oxalic acid flush followed by washing soda to purge any Dex-Sludge in their early cooling systems.

I used a mix of Cascade Platinum or Kirkland Signature dishwasher pods, then a water rinse, followed by citric acid and as much fresh water rinses as needed until the system was clear. Then I used either green or AMAM coolant depending on who was going to service the truck.

 

[Malo83]

I just drain and flush the radiator till the water runs clear