I was checking the fluid level in my car the other day and found some slime around the coolant neck...I haven't ever seen this before...I plan on doing a coolant flush soon but in the mean time I was trying to identify this substance...Any help--thanks

 

What was you antifreeze mixture? Some antifreezes can deteriorate over time (even before they are used) and begin to look like this. Also, minerals or other impurities in the water could react with the antifreeze and cause this.

Or, it could be a mixture of antifreeze, water, and a small amount of engine oil.

 

(1) Shows that the coolant has not been changed frequently enough.

or

(2) If the engine is a recent rebuild, it is the NORMAL contamination by some engine assembly lubricant. All new engines should have a coolant flush after breakin to clrean out the assemble sludge. SOP!

 

guess I need to get on flushing the crap out...thanks!