Auxiliary Water Pump Is Important for Cooling While Driving
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- Опубликовано: 7 фев 2025
- If your T1N Sprinter runs a little too hot in the summer, climbing hills or sitting idle, your auxiliary water pump may be the reason. The water pump that circulates when the engine is off, for the REST feature, warming the cab. That pump also assists the manual water pump and runs as soon as you turn on the key. Some vans have this pump bypassed. Many more have old pumps that quietly don't spin. This pump is more important than you might think...
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Dorman replacement pump: amzn.to/36qpHni
I never realized the rest button energized that pump and I thought it only ran when the espar heater was on. Thanks for making the video! Great info as always!
Oh the irony. The beginning of the video you're showing people why if they disconnect the rest pump, it does a disservice to the cooling system. In the middle of the video you discover you had done that exact thing on the other van with a chattering pump. Thanks so much for your entertainment and knowledge.
Yep... I share as I learn, and many of my lessons are related to my own past mistakes, one way or another.
thanks for this video ,i wrongly thought auxiliary pump was playing up because i could hear it running when i turned ignition on and i presumed (wrongly) that something was stuck on ,but after watching this video im now relaxed
Exactly why I made the video. I had one I could suddenly hear and it made no sense when it ran or did not. So I put a test light on it and realize it was getting power always, just not working half the time. Oops! We all learned something from it.
A different climate creates different necessities 😃
We use the rest button to keep the cabin warm while the van isn't running.
I must admit, I use the feature even in Florida... because it's there. We don't get much winter cold, but we do use the heater a week or two every year. LOL
Great video! I thought it was only for the rest function, but obviously it is used to help the mechanical one.
I thought I replaced that a year ago! now I know for sure you're my people. lol.
I always learn something from every one of your videos.
The auxiliary pump comes on at 150°, goes off at 1:10 whether you want it to or not if the pump's not working won't pump the water through the heater core can't get the air out of the heater core The car's about 1-ft higher than the radiator cap
While making the video I couldn't get either van to turn off the pump while the key was on. Perhaps when the weather gets cooler it will. I remember the chattering pump seeming very random, when it would come on and off. But now I see sometimes it might have been running quietly.
I also thought it was to cool the head on a hot engine after running. You should see how long it runs after shutdown on a hot engine. I had a VW diesel, had the same pump but no rest or espar heater feature.
That light is going to stay on the dash for a while. If I find that it stays on at odd times we will make another video about it. Stay Tuned...
The infamous aux water pump I can find little information on. PLEASE do a breakdown of the heater too for maintenance/cleaning or even what you'd recommend for replacement!
If you mean the boost heater, I'm sorry you will need to find someone in colder area. The ambient temperature needs to be low for these heaters to kick-on. We could only work on them about 2 unschedules weeks each year. :O)
@@FloridaVanMan haha, bummer.
Excellent video..thanks for the tips👍
Great video as always! My rest function stopped blowing hot air this morning. Super bummed as it's one of my favorite van features. Just checked the pump and no vibration or sound of water moving. Mine has an aftermarket undermount rear AC and the added hoses sit right in front of the pump aargh. I'm ordering a replacement now. Hopefully won't be too much of a pain in the a**. Do you recommend replacing hoses with it?
At this age none of the hoses are original and unless we can guess when they were replaced most recently it is hard to justify replacing them "just because...". If I were running a tight schedule where an overnight delay would cost me money or customers, I'd probably be more proactive about belts and hoses than I am currently. This is an personal choice based on budget and ability to repair minor problems roadside.
I live in Arizona and driving in and out of Phoenix in the summer can and will push the thermostat up close to 250. I was hoping this was my problem. My pump appears to be working (I can feel it running but don't hear water.) Flushed the coolant (prior owner put in green antifreeze but I don't think that would make a difference) and replaced the front radiator hoses. I did find that if I shut down the AC before climbing a large hill I can reduce the temperature by 20 to 30 degrees. If I waited too long to turn off the AC, it wouldn't help. by the way thanks for your videos. :-)
The output hose leads to a valve on the other side one the compartment. Pull one of those back hoses off and have someone turn on the key or press REST. If no water spits out, the pump isn't moving water. The pump spins a magnetic cup and the impeller is magnetic, inside that cup. It can spin the motor and not spin the impeller, hence no water circulation. If it starts pumping antifreeze, be ready to stick it back on the valve. Either hose on the back side of the valve should work. Use whichever is easier to get at the hose-clamp.
So.. hypothetically... if a T1N owner was having trouble with the engine getting hot when going up hills and they had no knowledge of this “rest” button prior to this stellar video... they should try turning that button on?
Yes. With the engine off press the rest button below the a/c button. A red light should come on. Then you want to go under the hood and feel the pump for vibration. The motor spins a magnet and the pump impeller is magnetic... So just because the pump spins doesn't always mean the water moves. It is best if you can hear water moving air bubbles in the lines, but sometimes you won't. Good luck and please share your findings here.
Florida Van Man, tried it!
The light came on, but no noise or vibration at the aux pump. Used a multi-meter and 12v are coming through the power lines. Time to get a replacement?
@@Fpv27423 Or pull one of the hoses off the valve on the other side of the engine, let the water stop leaking out then turn on the pump and verify it doesn't gush out of the disconnected hose. This will verify it is not running while (& being quiet). If you need one...
amzn.to/36qpHni
Great video guys!
Good information, love to watch your videos
By the way what kind stering wheel cover you have on,
It was on clearance sale at the local Dodge dealer when I went in for transmission filter on short notice.
Just found your channel and it’s a gold mine of information. Thank you for sharing your knowledge and experience. Im having issues finding the aux water pump on my 2003 3500. Could you tell me the general area it’s located.
On our north American models the aux pump is on the firewall, beneath the brake booster.
Good stuff
Interesting!
Great info, thx. I get that the REST function is meant to use residual engine heat to warm the cabin for a short period with engine is off, does the aux pump actually contribute generally to cooling the engine with the engine running just by pushing more coolant around? thx
Indeed it does. Without an aux pump the flow may be sufficient but a failed aux pump is a resistance in the path that cools the EGR and parts of the upper engine. Some T1N Sprinters in other countries do not have them and I am not 100% sure why not. Perhaps the 4 cylinder engine has better coolant flow? At higher RPM the regular water pump will push coolant faster than the aux pump, so the aux pump is able to spin independent of the motor by a magnetic drive. But at lower RPM the regular water pump seems inadequate for the upper coolant paths.
The rest function turns on the aux pump and dash fan to lowest speed, using the stored radiator heat to warm the cabin while re-fueling. It shuts off after 15 or 20 minutes but in my experience it gets cool and ineffective in under 5.
In my 2005 Mini one d r50 is always on... It is normal? (With base clima control, on cold or on hot position).
I confirm that on my mini it is connected to the cabin heater, in fact I used this pump to conveniently drain the cooling system, when i dissasembled the heater core.
Now there is some air left, how do I bleed it?
Proof read please. I've no idea what you are asking "one d r50 is always on". Are you talking about a mini-cooper or a small van? Bleeding air out of a radiator system is usually done by driving the van and topping off the coolant.
i have a
seat leon cupra 2009, and sometimes the fans are not starting for cooling and the water temp goes to 110 120, , the fans start only if i start the AC, i changed all the sensors, thermostat, waterpump, the fans, the radiator. i didn t change the auxiliary water pump, but i don t have errors on in, can be the auxiliaru water pump the problem?
I think spell checker beat up your comment, or I just don't know what a seat Leon copra 2009 is. If we are talking about a 2009 Sprinter, the electric fans should only come on when the a/c is on or when the van is in distress trying to avoid overheating. Is your clutch fan working?
If my aux pump isn’t working, could that cause heater issues? I have checked and replace the heater valve. I’ve cleared the heater core by flushing it both forwards and backwards with solution and hot water. I’ve checked the other hoses and nothing is blocked but I’m not sure if mypump is functional, so I’m curious if that would create a non-functional heater as well
The aux pump does nothing when the engine RPMs are up at highway speed but helpful at idle to keep the EGR and heater coil fed with plenty of coolant flow.
How to remove auxiliary pump of a Q7
What is a Q7?
Is there procedure on how to change the aux pump if it’s bad or it’s a simple plug and play ?
Super simple, no bolts. The wire plug pulls off, sometimes stuck a bit because it has been on a while. It helps to clamp the hoses and loose less coolant, then the pump will slide out of the rubber ring that is mounted to the wall. Twist and push/pull the pump out, new in, hoses on and add a bit of coolant of distilled water and call it a day.
We can often get them to work a while longer with a few good smacks form a hammer with the key on.
I have a question for the Florida van man may know. My heat booster is not working, I opened it and cleaned it up. Fan spins freely. I have voltage on all but 2 of the wires coming off the wire harness. I saw this video and thought, hmm maybe my recirculating pump isn’t working and my heat booster won’t turn on until it sees that functioning first. Any thoughts?
Here in Florida, we've never seen a working boost heater. That aux pump is important for equal engine cooling, so fix that soon.
Thank you for all these videos Florida van man! I had the green diesel firmware EGR bypass on my van. I believe that's how you describe it . It was "chipped". Maybe I regret doing that, maybe not, anyway, my auxiliary pump doesn't come on like you said it should and I'm wondering if that's because of the changes that were made to the van when I did that upgrade. I'm not having any redlining issues, just wondering if perhaps I don't need this auxiliary pump anymore, and that's why it never comes on? Any input would be appreciated (by you or anybody else.) thanks!
Surely not. Even with the EGR deleted there would be no good reason to disable the aux water pump.The EGR is a path to other engine parts that need cooling. If you don't get voltage on the wires to the pump when the key is on, start checking fuses and relays. It's two wires, power and ground, so easy to verify voltage any time the key is on.
Nothing happens on my sprinter when I hit the rest button, it doesn't even come on
That could be a bad button or maybe a fuse. The control panel with all the heat and air buttons is a known failure point. The AP200 code reader shows live data from this control panel. This may help find the culprit. Check it out here: amzn.to/2GD04Ft
@@FloridaVanMan I'll check it out, thank you
Hello! Can A malfunction of that pump cause rough idle?
No, this pump only circulates coolant. If your van has water cooled EGR like North American 2004-2006. Failure of this pump can contribute to an overheating and failing EGR. This would likely cause low power, not rough idle. An 8 to 10 second video recording of the engine would be the way to start diagnosing. Join me on Patreon for one-on-one assistance. floridavanman.com/donate/
would a p261F code in my 2014 GLK 250 bluetec be from an auxiliary water pump or the main water pump?
I've only read a little about this. On your 2014 you have a variable flow water pump that is vacuum controlled. Water can get into the vacuum lines and be very hard to diagnose. This is way outside of my experience, so just an idea to look into. ... a guess, if you will.
@@FloridaVanMan ok thanks! Did some research and it looks like water pumps fail all the time and leak coolant as you said. So does the aux water pump heat up some coolant and recirculate it in the heater core?
@@KenyonPayne The aux pump just circulates antifreeze. If you have an Espar heater, that will heat the coolant. The aux pump does push into the heater core, so you might notice cabin heat less hot when the aux pump is failed.
Great video! Is that part also called a coolant pump actuator? I have one blocked and on a trip, is it okay to keep going? In Colorado going to Montana so it’s cold out and if it’s just going be nearer to the red but mostly okay to make the last leg of the trip.
Get a second opinion from a different mechanic. Our T1N Sprinters don't have a coolant pump actuator, or a regulated coolant pump, which is what requires a regulator. Either your mechanic doesn't know what he is talking about, or he trying to make sure you don't. It is OK to continue your trip if this pump does not work, but the rest feature on your heater won't work for more than a minute of warm air then 19 minutes of cold circulation because the water isn't flowing through the heater core when the engine is off. The dash heat may not be as hot as it should be. And if your engine gets too hot it will be very hard on the EGR. This pump pulls water across the EGR for cooling it. The water will still flow without this pump, but slower.
Is it tied into the clock heater ?
We don't have a van with a block heater, but I would assume so. I have seen the espar heaters under the headlight and don't recall seeing a pump there. You are first to comment again, I see. You gave them all a fair shot. I was watching for you, and we had 14 views before you commented.
@@FloridaVanMan Nice video, Factory Espar relies on this pump as it does not have an integrated pump. If you have a bad aux pump the Espar will start and quickly shut off as it hits 180 degrees.
@@FloridaVanMan I feel like a dick. I would love to use a block heater as a water heater, they put out 5 kilowatts. handy little units when they work, repairing them is prohibitively expensive. I am working on the T1N at the moment, if I remember I'll have a look tomorrow, speak soon y' all
I live in australia and run a T1N , it had the espar block heater and all the auxiliary piping, I removed it all including the pump and the heater has notrouble bleeding air. I did a radiator flush and new coolant after removal of espar piping and pump, no problem ! I bought the standard hoses from the dealer which do not include the connection of the pump or espar heater. So these vans must come in some configurations without a pump or espar. No over heating issues in fact it appears to run a little cooler on the gauge.
I suspect your van does not an EGR and I am curious how your plumbing routes. Where does it come from to feed the heater core? If it is easy, pleas send a picture of your hood open to Bill@FloridaVanMan.com
Holly van! I didn’t know what the rest button was for... shame on me!
It seems many folks don't. With the key off, that button should run the water pump and dash fan on low, to keep the cab warm while you fuel up. It shuts off in 20 minutes, but it will be blowing cold air sooner.
Thank you,Florida Van Man !