Sprinter runs cold at idle and so is the heat

All,

I have a 2003 North American sprinter. I live in Minnesota and it is quite cold of course. I notice when I go start my van to let it warm up that the temp gauge is not getting above 110. In city driving, it only gets a bit above 110. I have to be on the highway for it to reach 180. Is that normal?

Second issue is I have a factory heater booster. I push the button and the little red LED comes on but my heat is not getting hot. As above, I have to be on the highway with the van all warmed up to get heat out of it. Is my booster not working or are they not much help when the engine is not all hot?

Thanks, wade

Wessels69p said:

I have a 2003 North American sprinter. I live in Minnesota and it is quite cold of course. I notice when I go start my van to let it warm up that the temp gauge is not getting above 110. In city driving, it only gets a bit above 110. I have to be on the highway for it to reach 180. Is that normal?

Click to expand...

Quite likely. Diesels are fairly efficient, which means there's not a lot of wasted heat ending up in the coolant.

Second issue is I have a factory heater booster. I push the button and the little red LED comes on but my heat is not getting hot. As above, I have to be on the highway with the van all warmed up to get heat out of it. Is my booster not working or are they not much help when the engine is not all hot?

Click to expand...

It's probably not working... try cranking your temperature knob all the way to "max" (the defrost symbol) which was another way to "request" the booster in some Sprinters.
With the engine idling and the booster turned on, you should first hear a tick-tick-tick of the booster's fuel pump, and then eventually (within 3 minutes) a whooshing-like sound near the driver's front tire (which is where the booster exhaust should exit).
If the booster cannot fire up in two attempts (total of 6 minutes), it stops trying.
When it's running, it can elevate the coolant temperature noticeably in 15 minutes
(there's another recent thread on this)
Vic/AquaPuttana has posted excerpts from the MB documentation on the exact start-up sequencing.

There are a couple of fuses involved with the booster heater, so check your fuse blocks on the driver's seat side to make sure they're all good.

--dick

Wade,
Perhaps you didn't get the memo..... you are never supposed to simply start your Sprinter in cold weather and let it idle to warm up. Very bad for your Sprinter overall.
You are supposed to get in and drive, possibly shifting the transmission yourself to keep the RPM up => 1500 RPM so it can warm up normally.
One option would be to go to an authorized Mercedes Benz Sprinter dealer and have them install the high idle option (either the fixed speed (1500 RPM) or the driver adjustable).
This would help to alleviate some of the bad effects of allowing your Sprinter to warm up at normal 680 RPM idle speed.
Since you live in Minnesota, that is perhaps why you have the diesel fueled Espar pre-heater.
Sounds like you need to have your pre-heater inspected and repaired.
The normal cold weather scenario would be to set the timer, or go out and start the pre-heater
1/2 an hour before you intend to drive away.
This will heat the engine coolant enough so you will have heat when you start the engine and drive off.
Another thing to check, if it seems your pre-heater is firing up correctly (it has a glow plug to
fire the diesel fuel sprayed under pressure into the small firebox under your left front fender)
would be to check that the small water circulation pump on the firewall (near the steering shafts) is actually circulating the warmed water through the engine and the cabin heater core.
Hope this helps,
Roger

It's been super cold here in mich too. They don't get very hot when it's cold at idle. It should reach operating temp driving any road but coolant temp drops fast even if you idle for more than 5 minutes. Have you checked your coolant lately?
I have to press my heater booster switch on and off bout three times for it to start. I think it's my pump. Maybe try that. Also you need to have over 1/4 tank of fuel I think for it to operate.

How do you know if it is working or not?

I just read all the info on not idling the sprinter. I just bought it less than a year ago. I'll be sure to stop idle warm ups. All the more reason to figure out why the heater booster is not working.

Wade,
You should be able to tell if the Espar Pre-heater is working.
Hit the red button to fire it up and look/listen under the left hand front fender.
You should hear the dosing pump pressurizing the fuel to the Espar pre-heater, then a "whoosh" as it ignites,
maybe a little gray to black smoke from the little exhaust pipe that extends into the fender well.
When you are sure the pre-heater unit is firing up and making heat, open the hood and look for the small
centrifugal pump with 3 coolant hoses.
One hose is on the end of the pump, one hose goes up to the heater core, one hose goes to your espar heater (I think? as it don't have the preheater).
You should hear the little pump running and perhaps put a finger on it to feel the vibration.
If the small circulator pump isn't working, you need to repair or replace it so it can circulate the warmed coolant to the engine and
the cabin heater core so you will have heat when you come out and start your Sprinter.
Be sure to allow the glow plugs to complete their cycle before you hit the starter.
Only takes a few seconds, just wait for the light on the instrument panel with the little coil in it to come on then go off.
Then start your Sprinter and drive off normally and you should be feeling some warm air almost immediately.
Did not intend to lecture you on the letting it idle deal.
It's more important on the later model NCV3 V6 Sprinters with the diesel particulate filter than on your T1N 5 cylinder, but
it's really not good for either one to idle when cold as it increases the emissions at a time when the emissions control devices
aren't up to temperature to burn anything off.
Roger

When it's below 20°f it takes a good 10-15 minutes for my '04 to get up over 120° and if it reaches 180° after a half hour on the highway I'm happy.

Just idling will almost never raise the temp up enough to run the cab heater. You have to drive it under load for a bit.

Thanks for all the advice. One more question. Will the heater booster run if the engine is off? Or do I need to start the van, then hit the button?

Hi Wade,
AFAIK if you hit the button with the engine off, the battery power will light the glow plug and the Aux. Pre-Heater will light and run if the outside temperature is below around 50 deg. F.
Did your Sprinter come with the Operator's Manual in the glove box?
If not you may find out a lot more information by searching on Espar.
You may even find an Operator's manual specific to your 2003 and the 2003 Espar Aux. heater.
Hope this helps,
Roger
P.S. I just did a search and came across a whole thread specifically about the Espar heater in Sprinters with .pdf files on it's operation.
Have a look at this:
https://sprinter-source.com/forums/...04&highlight=Espar+heater+controls#post114104
Also try this Espar specific manual with MB part numbers listed, schematics, pretty much everything you should need.
https://sprinter-source.com/forums/attachment.php?attachmentid=28150&d=1290057779

Wessels69p said:

All,

I have a 2003 North American sprinter. I live in Minnesota and it is quite cold of course. I notice when I go start my van to let it warm up that the temp gauge is not getting above 110. In city driving, it only gets a bit above 110. I have to be on the highway for it to reach 180. Is that normal?

Thanks, wade

Click to expand...

I drive around (off hwy) say 30MPH at 20*F and 90*F will come out of the vents after 8minutes , 110*F after 12 minutes of city driving. I have 2002 with a replaced aux coolant recirculation pump on the firewall and a winter grill cover blocking out the cold air from the rad. Never goes above 180*F and gets there much faster. That is without an Espar heater
A cheap winter grill cover can be made out of 1/2 water pipe insulation stuck on the grill, or a piece of vinyl cloth

Wade - I'm on the east side of St. Paul and can help you out with things if need be and I have a DAD. First, you need to block the grill with something as simple as a piece of cardboad (won't last long, better to use a painted piece of foam core poster board). Second, make sure your ESPAR heater is working as described above. If it is not, then you need to get it working. Often the elec. water pump will go out so the REST will not work and ESPAR not as functional at idle(though it should work). Water pump needs to work for ESPAR to work with engine off (you need a modification for this unless your van came set up with the 7 day timer - I can help you with the mod).

Overall, the van runs cold, block the radiator, get the ESPAR / boost heater working and you will be fine. Don't warm the van up, just start it and drive away slowly. Once you get the ESPAR set to run from a switch, you can prewarm the van in the morning (it is nice!!).

PM me and I can help you. Chris

I've an 06 with the booster heater .I'm in NC so doesn't get as cold here as in your area . but still use booster from time to time . I have had a few issues with mine. After starting the booster within maybe 5 minutes it will start blowing smoke from it .The smoke is from under the hood & very heavy . Thought the engine was on fire the first time. Did clean off the booster to make sure it wasn't oil or fuel burning .Smoke is so heavy I can't see just where it's coming from. But doesn't do it every time . The one way to know the booster is working, when I shut the van down. it sounds like turbo or even a helicopter winding down . Always get a laugh when folks walk by with a odd look trying to figure out just what they are hearing . Even here in a slightly warmer I have thought about installing a block heater , just to save the wear on the engine . If anyone has thoughts on this would like to hear them . My other locksmith has the 02, no booster heater . Some days can take him a half hour or so to get it started .The temp doesn't drop below 25 degrees , & has only been parked less then 12 hours . The dealer has checked it & everything is working fine as far as the glow plugs & relays goes .

.The smoke is from under the hood & very heavy .

Click to expand...

The booster (and Aux) heater should exhaust into the driver's side wheel well.
If you look around in that area, you should be able to see the wallet-sized muffler in there.
There is a corrugated metal exhaust pipe (hose?) from the heater to the muffler.
If the hose is damaged (or corroded through) in the engine compartment, then the heater's exhaust will be dumped there.

--dick