Ok...so I am rotating tires, cleaning battery terminals...usual minor maintenance when I see a drop on the floor towards the front. Grab the light and apparently my truck was previously owned by Mr Spock.
So... it obviously seems to be coming from the thermo housing. No biggie...new gasket and goop and she will be good to go. Maybe a new thermo while I'm at it. But .. why is it crusting up like that? Almost looks like calcification.
I assume it is having time to dry cause the leak is so slow but figured I would get a second opinion.

Thanks all!

live long and prosper.

 

The GF's Commander had a slow leak too, same crusty crap on the heater hose. I cleaned it up with brake cleaner after the fix, no problem.

 

Oops.... missed the picture

 

Almost all liquids have some suspended (dissolved) solids in them and when they dry the solids will be left behind.

 

And some are corrosive......

 

Yeah that’s my other worry. This had been seaping for some time but I will be cleaning this up and getting a new thermostat for it tomorrow.

Thanks for the info guys!

 

I'd suggest getting a new OEM housing, too. Likely the old one will have some deterioration or issues.

Also be sure to use OEM-only Tstat. It has a gasket that wraps around to the top and bottom of the Tstat. I tried the other one from Stant- couldn't seal it no matter what. OEM and done.

Good luck!

 

My 2 pennies, I'd go after a billet tstat housing, too. Got one off eBay for 30 bucks

 

If that were my ride, flush the system with distilled water, change over to an extended life coolant, new stat and a billet t-stat housing.

 

With all due respect Dan, no ELC in a '99 unless it's had the injector cups replaced with updated sealant.

 

330k on the clock ... still the original injectors and cups.
Unfortunately, no parts found locally today. So it will stay as is for now. Need it tomorrow to drive to work so...

 

Walleye, mines a L99...upgraded cup sealant😉...e99 were the ******* childs

 

Thanks for that, I thought it was all '99s

 

Gotta love those mid year changes.

 

So is yours an E99 or L99?