Coleman 17B AC Dripping Inside? Why It Happens and the Simple Fix We Use
If you own a Coleman 17B, or you have spent any time in the owner groups, you have probably heard this one: the AC drips inside. People report it landing on the bed, running down the wall, or hitting them on the head in the middle of the night. It happened to us too. The good news is it is not a broken AC, and the fix costs less than a tank of gas.
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In this post
- Why the Coleman 17B AC drips inside
- The fix: park it at a slight angle
- How we do it with leveling blocks
- The other AC problem: mud streaks down the side
- What the newer models changed
- Coleman 17B AC FAQs
Watch it in the video
We cover both AC issues in our one-year review. These links jump straight to the moment.
Aaron Goes Outdoors walks the 2025 Coleman 17B after a year of camping, including both AC issues covered here.
▶ See the AC inside leak warning in the video
▶ See the AC drain streaks in the video
Why the Coleman 17B AC drips inside
The 17B does not have a rooftop AC. It uses a window-style unit built into a cabinet on the wall, up by the bed. The vent you see on the outside of the camper is the back of that same unit.
Like any window AC, it pulls moisture out of the air while it cools. That water collects in the bottom of the unit and is meant to drain out the back, to the outside. That only works if the unit tips slightly toward the outside.
If the trailer is sitting dead level, or leaning toward the door side, the water can run forward instead and drip out the front of the unit. That is when it ends up on the wall, the bed below it, or you. Nothing is broken. The water is just following gravity.
▶ See where the AC drips inside in the video
The fix: park it at a slight angle
The fix is simple: park the camper so the off-door side (the side without the entry door) sits just slightly lower. That tips the AC unit just enough that the water runs out the back to the outside, the way it is supposed to, instead of spilling over the front edge.
We do this every single time we set up now, and we have not had it drip inside since. The key word is slightly. You are not trying to make the camper feel tilted inside. You just want enough lean that water never pools toward the interior.
How we do it with leveling blocks
Most campsites are not perfectly flat anyway, so you are already leveling side to side. We just level with the AC in mind. We use stackable leveling blocks like these RVMATE RV leveling blocks. Here is our routine:
- Back into the site and check side to side level.
- Remember the off-door side is the one you want slightly lower.
- If the door side is low, stack blocks under the door side tires and pull onto them.
- Aim for close to level with a slight lean toward the off-door side, not perfectly flat and never leaning toward the door.
- Chock the wheels, unhitch, and level front to back with the tongue jack.
If your site already leans the right way, you might not need any blocks on that side at all. If it leans the wrong way, a block or two usually fixes it.
The other AC problem: mud streaks down the side
Once the AC is draining outside the way it should, you will notice a second issue. The water comes out the back of the unit and runs straight down the side of the camper and leaves dirty streaks, especially after a dusty trip.
This one is cosmetic, not a leak. Our plan is to add a small gutter and downspout so the water drips away from the wall instead of running down it. We have not done that yet, so we will update this post once it is in and we know how well it works. Until then, a quick wipe down after each trip keeps it from setting in.
▶ See the drain streaks in the video
What the newer models changed
Coleman clearly heard about this one. The newer 2027 models add an interior lip on the AC to catch drips before they reach you. If you are shopping new, that is worth knowing. If you already own a 2025 or 2026 like ours, parking at a slight angle gets you the same result for the price of a few leveling blocks.
Coleman 17B AC FAQs
Why is my Coleman 17B AC dripping inside?
Almost always because the camper is sitting level or leaning toward the door side, so the AC condensation runs inside instead of draining out. Park with the off-door side slightly lower so it drains outside.
Is a dripping AC a sign the unit is broken?
Not in our experience. Ours runs great. The drip stopped as soon as we started parking at a slight angle. If it still drips when the camper is angled correctly, have the AC unit and the seal around it checked.
Do I need special leveling blocks?
No. Any stackable RV leveling blocks work. We use blocks like the RVMATE ones linked above.
Did Coleman fix the AC drip on newer models?
The 2027 models add an interior lip on the AC to catch condensation. Older models do not have it, so angling the camper is the fix.
How do I stop the AC drain from streaking the side of my camper?
A small gutter and downspout to direct the water away from the wall is the plan we are working on. Until then, wipe the streaks down after each trip so they do not set in.
Final thoughts
The Coleman 17B AC drip sounds scary the first time it happens, but it is one of the easiest problems on this camper to fix. Park with a slight lean so the water drains outside, keep a set of leveling blocks in the truck, and you will probably never think about it again.
For the full long-term take on the camper, read our one-year Coleman 17B review. For the upgrades that made the biggest difference, see the top 10 things we bought for our Coleman 17B. Want to try a 17B before you buy one? You can rent ours here in Cedar Falls.
For more 17B content and honest trip reports from the Midwest, subscribe to Aaron Goes Outdoors on YouTube.