Friday, December 8, 2023


I winterized the RV and it still froze. Why?

Dear Dave,
I recently incorporated a temperature controlled 100w ceramic heater lamp, designed for a fish tank, into my water closet, hopefully to keep the manifold and other nearby exposed lines from freeze damage. I always blow the lines and then pump antifreeze thru all of the faucets via the winterize setting in the manifold. But that apparently wasn’t enough for the manifold in the Big Freeze we had here in 2021. In addition, my 5th wheel has an underbelly and I’m thinking of cutting a strategically placed hatch to install another heater of the same capacity while it sits in storage during the winter months. Any thoughts? I have to wonder why underbelly heaters are not built-in. This coming storm will be its first real test. —Ray, 2015 Jayco FLQS 339

Dear Ray,
What was the low temperature of your “Big Freeze” that evidently froze your manifold last year? Most of the cheap, large box store pink stuff has a -50 degree burst protection; however, I have seen a few -30 degree versions.

If you are using the -30 degree version, temperatures here in the Midwest just plummeted to -15 degrees. However, with a 40-50 mile gust it was recorded at -50 or lower, which would freeze your water lines with this type of RV antifreeze.

I believe the “manifold” you are referring to and water closet is actually the service center and water lines with elbows and “T’s” to divert water to different parts of the coach. This is an example of one in a Class A motorhome. You can see the RV antifreeze in the lines.

You can get RV antifreeze that is rated to -100 degrees. That should eliminate your freezing issues unless there is the possibility that you might not have gotten all the water from some of the lines. Since there are so many valves and lines going in different directions, it is not uncommon to have a line that does not get purged.

One last question I have is why the need for RV antifreeze if you blow all the water out of the lines? If you use compressed air, I would just get all the water out and not put anything else in. Drain the water heater and fresh water tank, and open all the low point drains. Then connect the air compressor dialed down to 40 psi and open the farthest faucet until it blows air, then shut it off and do the rest. Don’t forget the toilet and sprayer, outside shower, and the ice maker if you have one. For the ice maker, remove the filter under the sink and shut off the valve, then cycle the ice maker a few times until there is no water.

You will need to run the onboard pump a little to get the water out of the pump and lines, as the city water hoses bypass the pump when using compressed air. If you get all the water out, you will not need RV antifreeze.

 You might also enjoy this from Dave 

Can we just open RV’s drain valves to winterize?

Dear Dave,
Our RV will be stored in Myrtle Beach, South Carolina, for the winter. It has several low-point water drain valves that drain most of the water out. Do you think we still need to have it winterized to be on the safe side? I really enjoy your column; I read it every week. Thanks for any help. —Winfred, 2019 Jayco White Hawk 32KBS

Read Dave’s answer.

Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”

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Dave Solberg
Dave Solberg
Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club. He has been in the RV Industry since 1983 and conducts over 15 seminars at RV shows throughout the country.



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Denny Napora (@guest_216570)
11 months ago

Sorry Dave, but “wind chill “ does NOT affect things like sealed water lines and such.
It is the effect or feel of combined cool temperatures and wind speed on human skin.

Dan Cunningham (@guest_216354)
11 months ago

Windchill does not affect the antifreeze in any of the lines. Windchill only affects warm-blooded mammals or something that has heat such as a vehicle radiator but only to ambient temperature, never lower.

Roger (@guest_216300)
11 months ago

Could the higher winds Force colder air into the compartment, where something may be more likely to freeze?

Last edited 11 months ago by Roger
Casey (@guest_216282)
11 months ago

I blow my lines and use RV antifreeze. Blowing the lines doesn’t remove 100% of the water. Some residue is left and if enough collects in a low spot and that happens to be a fitting or pump it may split. RV antifreeze is relatively cheap and beats fixing broken plumbing. And like others have said, wind chill will lower the objects temp quicker but does not lower it past the actual temp. If that were the case you’d see things freeze up on a 40 degree day with high winds and we don’t.

B Sears (@guest_216272)
11 months ago

As a Flight Instructor I was going to point out that the temperature is not based on wind speed but I see everyone else has shot down the comment about inanimate objects. Lol carry on people.

Ray Leissner. (@guest_216271)
11 months ago

Actually I was hoping for comments regarding my use of a low power ceramic heater. The temps in this last storm got down into the single digits one night and stayed in the teens for almost more 2 days. The 5th wheel is outside and remote and the water closet, where I had issues from a much deeper freeze last year, is in tight quarters. Being afraid of starting a fire, I utilitzed a 100w ceramic fish tank heater powered with a temperature controled 110 outlet, hoping that would be enough to keep a very tight, intricate manifold that suffered freeze damage last year dispite purging. I can only assume the manifold did not drain enough, hence the 3 prong approach, purge, antifreeze and heater. If last year taught me anything, its that I hate plumbing, so I tend to go overboard to avoid it. I won’t know if I was successful or not until spring, but at least no one has called to say my RV has burned down.

rich (@guest_216262)
11 months ago

i’m fairly certain wind chill does NOT affect water lines or any other inanimate object. wind chill is felt only by living beings.

Bob (@guest_216252)
11 months ago

The -50 is the wind chill, not the actual temperature. The wind can bring the temperature down faster, like blowing on something hot to cool it off. This is something I thought everyone knew. Water freezes at 32 degrees, if the temperature is 35 no matter how hard the wind is blowing the water will not freeze, but the wind chill could feel much colder.

Spike (@guest_216250)
11 months ago

Above is a link to Splash brand’s RV antifreeze fact sheet. -50 Splash starts to freeze @ +20F. -100 @ -20F. But the freeze point protection rating is a plumbing industry standard as to when it would burst a pipe of a certain material.

Net…many of us will see “frozen” RV antifreeze, but that doesn’t mean our pipes will sustain damage, as long as the temp stays above the burst point.

Doug Christen (@guest_216247)
11 months ago

wind chill only affects warm blooded creatures

Barry (@guest_216245)
11 months ago

RV antifreeze has a BURST LEVEL. While it can and does freeze, the important factor is unlike water it doesn’t EXPAND. This means while the liquid in the lines may not flow, it will NOT burst pipes, valves, or fittings at or above the burst rating.
Oh yes, and Wind Chill (wind speed) has NO bearing on the the actual temperature.

Steve (@guest_216244)
11 months ago

Agree with others here about wind chill temps not effecting fluids. Sometimes Dave isn’t as smart on these things as he should be. Makes me question other answers he gives and how credible he really is (isn’t?)

Paul (@guest_216284)
11 months ago
Reply to  Dave Solberg

So why not go back and fix the article to contain accurate information about windchill vs actual air temperature? It is still incorrect….

Ken (@guest_216251)
11 months ago
Reply to  Steve

X 2

Rock & Tina (@guest_216228)
11 months ago

“However, with a 40-50 mile gust it was recorded at -50 or lower, which would freeze your water lines with this type of RV antifreeze.” That is demonstrably incorrect. Water and Antifreeze are indifferent to wind chill. The wind could be blowing at 100mph and water will not freeze at 33F. Wind chill can affect the rate at which a fluid will decrease in temperature but it has zero affect on the final temperature of the fluid. If the measured temp was -15 then the fluids will drop no lower than -15 no matter what the wind chill.

T G (@guest_216230)
11 months ago
Reply to  Rock & Tina

Good explanation.

John S (@guest_216231)
11 months ago
Reply to  Rock & Tina

True, I just submitted the same comment. This is similar to the “heat index” readings.

Jewel (@guest_216232)
11 months ago
Reply to  Rock & Tina

exactly! Wind chill is only a feeling, as in “feels like -50” and inanimate objects cannot feel.

When temps are expected to drop so low, we purge with air and/or drop some antifreeze in the lines for low points. We also keep the furnace on at around 50° to keep underbelly heated since we store ours at our house.

Tom (@guest_216227)
11 months ago

This is the week that will test our winterizing method.
Hope everyone is safe and warm.

Greg (@guest_216226)
11 months ago

I just noticed that a bottle of -50 RV antifreeze inside my 5th wheel is froze solid. Out side temp was around 0. I did blow my lines out, but used the anti freeze in the traps and in the lines for added protection. Now I wonder if I am protected.

Carol (@guest_216229)
11 months ago
Reply to  Greg

After the thaw, let us know the outcome (reply back here). Thank you

Jeff Myers (@guest_216238)
11 months ago
Reply to  Greg

Was it really frozen solid? Like a block of ice? That antifreeze stuff will turn slushy, but that is normal.

Dan (@guest_216240)
11 months ago
Reply to  Greg

I’ve always used the pink water with no problems, but now I’m wondering if it has gone the way of so many things we buy, “Let’s see how cheap we can make it and still sell it”. I always have an extra jug of it in the shop, so I’m going to put it outside to see if it gets slushy.

Spike (@guest_216246)
11 months ago
Reply to  Greg

You should be fine. I’m surprised that, in addition to saying that wind chill affects inanimate objects, Dave did not mention that RV Antifreeze will become solid (freeze) at a temp above its burst point. However, the chemicals in RV antifreeze do not expand as significantly when frozen as water does. So even when it becomes a solid, it won’t break pipes until at least its burst rating.

One thing I do is to always leave faucets open after winterizing. This helps alleviate pressures in the system. I also use the low point drains to take some of the antifreeze back out. If one is first blowing out lines, then pumping in antifreeze, you are really only trying to protect spots that may have held some water or can’t be blown out like dishwashers or washing machines.

Last edited 11 months ago by Spike

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