Coolant tank empty..

Ive had my 2000 Venture for the last 5 years, it currently has 65K miles. No one has hardly driven it that much for the past year, maybe about 1 time a week and occasionally on some short trips. But today after I noticed my temp gauge has risen faster than usual and my van eats up gas like no other. I checked the tank and noticed it was almost or near completly empty. What could have caused this? The coolant isnt leaking from anywhere, all the hoses look to be in good condition.
I was wondering what could have caused all the coolant to be gone?
Do I have to flush out the whole system & how do you do that?
Can I just add coolant to the tank?
How do I know what coolant to use? Can I use the already concentrated coolant from kragen/autozone?

Sorry for all the questions, just need them to be answered or helped with. Thanks

Same thing happened to me in just the last week. Low coolant and no OBVIOUS leaks (to me anyway!). Intake manifold gasket leaking. I would have that checked ASAP. You dont want to drive around with it leaking because it can do engine damage. The antifreeze leaks into the oil thinning it out and it loses lubrication. The dealer is expensive but my garage is doing it for $500 next week. No offense to the hubby--he could probably do it but these vans are a pain to work on!! My Venture is also a 2000 with 63,000 miles and I cant wait to trade it in!!!

How did you figure out the intake manifold gasket was leaking?

Had a shop look at it. If there is one you trust, take it there. They saw it as soon as the popped the hood and starting looking around. I had it in the shop for another issue. But in the last week, had to add antifreeze because my resevoir was empty. I had no OBVIOUS leaks either. There have been some what look like oil spots on my driveway so I kind of had a feeling that is what was wrong as soon as I had to add coolant. But I was in intake manifold gasket denial!! LOL! Van never ran hot or anything like that. Just dont let it go. Expensive repair but replacing the engine is more expensive! This forum has been very helpful for me and my crappy Venture!:wink: I would have it checked anyway since it is just such a common issue with these vans

The LIM is often the case, but don't always presume that is the case. The leak can be internal or external. If you take a long drive and open the hood soon after and smell something "sweet", it's coolant. Take a look at your oil cap, inside the opening, and the bottom of the PCV valve. Moisture in the oil will condense on these areas and form a frothy like substance that looks a little like mayo. However, in cold weather the exact same symptoms can form with just water condensation if your van is never driven hard enough long enough to burn off the moisture in the water.

Depending on the age of the vehicle, I would also look at the network of coolant lines that feed the front (and rear if applicable) heater cores. The connectors, hoses, and clamps can deteriorate over time and slowly leak. You can purchase a UV dye that you add to your coolant that will glow under a real black light. It makes detection easier.

If you really want to make sure that it's a leaky intake manifold and not something else, you will have to pay $20 to get your oil analyzed by a laboratory.

Like everyone mentioned, take a look at the oil and see if its there. Sometimes the antifreeze might not be getting in the oil(yet), but it is leaking in the intake port of the closeest cylinder and being burned through the combustion process. Also I wouldn't rule out a head gasket problem too. But before that, make sure you havn't got an external leak. Rule out all the easy stuff first, before digging deeper.