coolant goo - lime jello on radiator cap

[Potomac30]

So what's the green jelly stuff on my radiator cap? It appeared after my last coolant flush with Prestone. It's been 12,000 miles now and the stuff is still packed in around the cap and spring... it cleans off easily.
1993 Explorer 4x4, 90,000 miles. last flush at 78,000, new t-stat at 54,000.

 

[budwich]

I think its an indication that you are running with a greater concentration than 50-50.

 

[X6StringerX]

Taste it and get back with me. It could just need some sugar.

 

[Potomac30]

Taste it and get back with me. It could just need some sugar.

No thanks, I never cared for the lime flavor.

 

[Potomac30]

To answer my own question

I looked up some other sources and found this:

Inferior antifreezes are high in silicates that make them susceptible to inhibitor "fall out" This causes separation and is commonly referred to as "Green Goo"

Under Concentration of coolant/anti-freeze will cause:
liner or water pump impeller cavitation
general corrosion
deposits on heat transfer surfaces
plugging of the system with corrosion products

Over Concentration of coolant/anti-freeze will cause:
water pump seal seepage
solder bloom or solder corrosion
hose and gasket seepage
plugging of system with precipitates or gelled additives
slush formation and resultant overheating

 

[X6StringerX]

I've never heard anything bad about Prestone. I've used it for years in my vehicles and I really don't think it is an "inferior" product. My money would be on over-concentration. Any antifreeze will gel up if you don't have a sufficient amount of water. Luckily, the solution to this little problem is simple. Suck some anti-freeze out and add some water in it's place.

You sure you don't like lime?