Hey everyone, just picked up my first Dakota and had an issue with it. It's a 3.9 1998. There's what seems to be an expansion tank for coolant on the driver side of the bay, but the cap on mine is busted off. Thats all that is left is a dipstick.I found this picture and its the yellow cap circled in red. Just wondering what exactly it is as well as where to look for leaks. Nothing registers on the dipstick. I'm assuming I'll have to replace that entire black tank on the right side? Thanks for help.

is that a picture of your truck?? bc if so the cap on my reserve tank is not attached to anything it just snaps over the top of the reserve tank opening and when i take it off i have to be careful not to do it and yes my truck is a 98 w/ 3.9 so if that is a picture of y our truck then i would just addthe needed coolant and see what happens, only replace it if you find a leak bc mine was dry when i got it too

That is the overflow for the radiator coolant. Those yellow caps come off easily. Just go buy yourself some coolant and fill it up.

Thats just a random picture. I added coolant and it drained right out of the bottom of the truck.

Thanks, thats what I tought it was, but it leaks. Are there any fittings or hoses that are prone to failure? Ill check those areas ASAP.

On mine there was a dime sized hole in the tank itself
I got a universal tank from jcwhitney but it looks like crap

Is it easy to remove the tank?

couple of bolts, a hose,
thats really it.
(as i remember, it was a 2 years ago)

Mine does the same thing, its not a big deal if its empty its just a reserve.. but ill be fixing mine soon, i looked for hoses and crap to and it seems like mine leaks close to the firewall thats where the puddle always is... i just stopped refilling it, becuase i would go through the crap like nothing as soon as i pour it in it would just drain out in likw 10 or 15 min.

Cool, Thanks everyone, I picked up a new tank for 30 bucks and Ill install it friday, Ill report back with results.

Wasn't a big deal to reinstall, I had a hole in the original tank. Had to remove the front bumper to take the old one out though. Thanks for the help.