Yikes! The smell came back...

[The Critic]

During the May of this past year, I drained the awful smelling, two-year-old Prestone DexCool from the '96 Saturn SL2.

The system was refilled with tap water after draining the radiator and the block, idled for 10 minutes, then drained again.

3.75 quarts of Prestone All Makes/Models "Universal" fluid was installed with enough tap water to top-off the system. Resulting mixture was a clean, yellow-green fluid smell sweet. Surprisingly, one drain/refill with water was enough to remove nearly all of the red color dye from DexCool.

Fast forward to today, August 2006. The coolant is still full, and a quick extraction using a straw shows the fluid to be yellow/green, and transparent. But the smell has returned, the fluid no longer smells sweet. It stinks like dirty socks.

Any ideas?

Thanks.

 

[CBDFrontier06]

I have no clue what would be adding the dirty sock smell..the only thing I can think of is a head gasket leak that is somehow passing exaust gases into the coolant, in which case you'll want to keep your eye on the overflow tank while the car is running and look for the telltale bubbles.

On another note, I would advise against using tap water as a coolant fill. Minerals from the water will fall out of suspension and attach to the walls of the radiator and water jackets in the block and head.

 

[The Critic]

Thanks.

There are no signs of coolant loss, nor oil in the coolant.

I talked to some quick lube guys and they're telling me that most of the newer GMs they're now seeing with the "Red" colored DexCool, possibly made by Prestone, has a similar smell. Perhaps it's normal?

 

[CBDFrontier06]

Is the green stuff you added just regular Prestone, or is it some funky GM formula that just happens to be green?

 

[The Critic]

I installed Prestone Extended Life, "All Makes/Models" fluid. The stuff is yellow/green, and looks NOTHING like "traditional" silicated coolant. This is the stuff that is now sold in the yellow jug, or has been since the fall of 2004. It advertises a 5-yr/150k service life but should really last virtually forever due to the lack of sacrifical components such as silicates and phosphates.

 

[Ray H]

What is your evidence for your statement that phosphates, as used in many Japanese OEM long-life coolants, are "sacrificial"?

 

[The Critic]

Should have made it more clear. I was really referring to the "traditional," American "green" coolants that relied heavily on the silicates and phosphates for protection. I wasn't referring to the "HOAT" Japanese coolants that contained phosphates, as the phosphates in those coolants evidently are not sacrificial given the long service interval.

Any ideas on the odor?

 

[another Todd]

First off, I try to never use anything that is universal. Nothing is perfect for everything! Second I only use DISTILLED water in cooling systems, in my area there is a lot of calcium in the water plus clorine. Neither one is good for cooling systems. I currently use dex-cool in some vehicles (barrs stop leak required), and peak regular green coolant in the others. Can't speak on the smell you are experiencing, I have never intentionally sniffed my coolant.

 

[The Critic]

Prestone returned my e-mail and said the odor is harmless provided that the coolant looks OK. I'll be doing any change this coming fall when the thermostat is replaced, and I'll run some cleaner through the system and use Distilled Water for the final fill.

 

[Ken2]

You might try a coolant supplement that cleans the system from now until you replace your 'stat this fall. RMI-25 is one product of this type.


Ken