Espar coolant heating system / REST

I have 2 separate but possibly related problems with my Espar unit and my REST system.

1. The coolant pump (REST) isn't working properly. It will activate when the van is cold, but sounds like it's having trouble pumping. When the van has been driven and then shut off, it won't activate. I suppose this pump will need to be replaced - does anyone know the part #? (EDIT: see below)

2. My engine heater (Espar unit) is not working as well. I think I caused this....

Last winter, I had the hood open with the engine running and was cleaning salt off the motor / engine compartment with water. The Espar unit was on - and I mistakenly shot some water in the air intake (you know, the one with the huge NO WATER sticker on it ).

About 10 seconds after realizing I got water in the main intake, the Espar started billowing smoke. I assume that I damaged the unit - at least the glow plug. From the Espar website, the unit has replacable parts. I am going to attempt to repair it instead of replacing the entire unit - must be $1000 at the dealer

My second question is - does the Espar know the coolant pump isn't working? Perhaps that is preventing it from firing - assuming I didn't destroy anything in the Espar? I also haven't tried to re-prime the Espar fuel pump... will attempt that first.

Thanks in advance for replies -

Also - troubleshooting guide... http://www.espar.com/documents/airtronic_hydronic_troubleshooting.doc

Possible recirculating pump part # - MB A0018351364 Dodge 05098398AA - PUMP RECIRCULATING

From only a part of a long thread on finding, removing, repairing and replacing the recirculating pump (referred to at the Coolant Pump in the Sprinter repair manual) on YahooSprinterVan at http://autos.groups.yahoo.com/group/sprintervan/message/34288 [see also :

RE: [sprintervan] Aux Heater...where is the water pump?

maxzoom999 wrote:

"My 2005 Sprinter aux heater is not working. It turns on and heats up and blows hot air out the exhaust. But only cool air blows into the cabin and the engine coolant temperature doesn't rise"

Is Your temp control switch on the dash on max?

"The booster heater and regular heater work normally when the engine is running. The rest feature also works fine when the engine is off."

"I cleaned out the aux heater exhaust but that didn't help. So I'm guessing it is the water pump."

the rest feature should blow cold air into the cabin (with the engine off, but warm) if the aux pump is not running. The fact that the aux heater does not shut down after a few minutes also suggests that the pump is ok.

"Where is the water pump for the aux heater located and how to fix it?"

On the (silver ) intake manifold on the engine sits the rectangular EGR valve. a 4/4" hose comes off at the side and angles down to the area under the brake booster. at the other end of this hose,under the booster, is the aux coolant pump. It should be humming and gently vibrating when in operation.

"What is the Dodge part number for this water pump?"

Dodge, mopar 5098 398 AA $ 271.-
Merc Benz 001-835-1364 $ 246.-
Bosch 0392020026 $ 186.-
Bosch generic version of the same pump 0008356964 (use this number for searching the internet if looking for 3rd party suppliers)
Volkswagen 251 965 561 $ 174.-
Europarts 5098398AA $ 100.- (europarts-sd.com)
AutohausAZ has it at less than $60

this pump is also used on 2003 Ford F 150

See also http://autos.groups.yahoo.com/group/sprintervan/message/34309:

Hello List

The (Bosch) electric coolant pump is a marvel of minimalist engineering.

After I installed a replacement pump in my 2004 Sprinter I decided to have a closer look at the failed unit. The fact that the pump only lasted for a bit over 2 1/2 years made me wonder what went wrong.

The pump impeller housing easily unscrews from the motor. It is a plastic injection moulded piece and completely sealed (glued) together and in fact driven by a spinning magnet propelled by the motor. No chance of fluid leaks due to failed seals.

This also means that an obstruction in the water side of the system could stop the impeller from spinning while the motor still motors on. However the chances of that happening are slight due to the ample clearances in the pump housing and, unless You topped up the radiator with tadpole infested pond
water......

Right, back to the motor itself.

There are no bolts or screws to open up the unit. Instead the plastic end caps are held in place by 3 sets of metal tabs of the (zinc) housing itself. they can be pried back with a small flat screwdriver and then the back cover can be pulled away.

the cover contains the electric plug receptacle and the spring loaded brushes.

The brushes had worn down about 60% and the resulting accumulation of carbon dust had collected inside the sealed motor casing until it jammed the armature.

since the unit is sealed there is no way for the dust to get out, hence the failure.

I used compressed air to remove the dust and re assembled everything. In order to get the (spring loaded) brushes back onto the commutator I had to drill a 1/4" hole into the housing to get the small screw driver inside to coax the brushes into place. This hole will also help to dislodge future carbon dust accumulations without having to take the pump out.

A quick bench test brought the unit back to life. Now I have an "emergency spare".

From a manufacturing point of view the pump is brilliantly simplistic, easy to assemble and "non serviceable"

Probably doesn't cost much more than $20 to make.

Retail $ @ the parts counter from $120.- to 275.- lots of room for mark-ups.

From the consumers point of view it's a dilemma:

The pump seems to last only a (too) few years. it's failure causes the Aux heater and REST feature to shut down and I can only guess what the replacement would cost if performed at the dealers.

I will have to look into sourcing a more reliable (in the long term) alternative.

Let's hope my experience was an isolated one, I'll know in about 2 1/2 years.

Tom Tollefson

For a picture of an Espar sending out a steam cloud, see https://sprinter-source.com/forums/showpost.php?p=319&postcount=2

TV Sprinter said:

My second question is - does the Espar know the coolant pump isn't working? Perhaps that is preventing it from firing - assuming I didn't destroy anything in the Espar?
Thanks in advance for replies -

Click to expand...

If the external(the only one there is) coolant pump is not working the Espar heater will experience a rapid overheating of the, now internally trapped, coolant and shut off prematurely. Doktor A

OK. I removed the recirculator pump, and did the above described 'rebuild' to it. It's functioning again, but from the looks of the brushes in the motor, it will work for about a month before it dies - so I will be ordering a replacement from Europarts.

My recirc pump seems to be running frequently - not just when the REST is activated. I can feel it pumping when the engine is running, but haven't been able to tell exactly when this happens.

With regard to the Espar heater - no dice. It won't fire, and the voltage at the pump shows about 9 volts (made sure connection to meter was good, pump connections are somewhat hard to get to). I plan on having the dealer hook up the DRBIII and telling me what is wrong with it.

Thanks for the help all.

TVSprinter

What type of controller are you using with your heater?

I'm fairly certain DRBIII doesn't provide for heater diagnostics, but the generic digital timer that's available for the heater control does.

Whereabouts are you?

Simon

No controller - I don't have the digital in-dash timer unit.

I thought that the DRB unit could talk to the heater?

I'm in the northeast US.

TV Sprinter said:

I thought that the DRB unit could talk to the heater?

Click to expand...

According to the Description section, it says it can.

Woah - it says that you must be moving >5mph???

TV Sprinter said:

Woah - it says that you must be moving >5mph???

Click to expand...

A mistake on my part. I included the section for the rear aux heater.

Here's the correct one the explains is better (bottom right)...

I stand corrected!

Simon

Argh. It's hard to follow these posts because you guys are refering to the AUX CABIN HEATER the same way as the HEATER BOOSTER. They are not the same. It's the HEATER BOOSTER I'm trying to get fired up. I don't have an AUX CABIN HEATER.

I remember using the REST unit way up in Minnisota last winter and it worked great, but when the motor is cold there is no more heat.

The BOOSTER will not help with that situation, but it will get my motor heated up faster in the cold weather, but here at home in California where the temperature is 70 degrees every ding dang day of the year I can't get the darn ESPAR HEATER BOOSTER to fire up!!

ARRRGH!

BULBASOR said:

Argh. It's hard to follow these posts because you guys are refering to the AUX CABIN HEATER the same way as the HEATER BOOSTER. They are not the same. It's the HEATER BOOSTER I'm trying to get fired up. I don't have an AUX CABIN HEATER.

Click to expand...

Both actually use the same heater that is located below the battery or the driver's side headlamp. The biggest difference is one (heater booster) operates with the engine running the other (aux heater) does not need to.

First thing to do is to check your dosing pump.

WHAT???

Am I hearing this right? The REST gets it's heat from the ESPAR UNIT? Now I'm really confused. I thought the REST was RESIDUAL ENGINE HEAT UTILIZATION. I thought that the REST just pumps the warm water in the engine around in circles so you can run the heater with the engine off. That only works as long as the engine stays warm. After about three hours the engine is cold and the REST just blows cold air.

I thought the HEAT BOOST actualy HEATED THE WATER with a little diesel fire box. It's got a little muffler in my wheel well, but no exhaust comes out when I turn it on.

BULBASOR's REST unit works fine. It's the little fire box thingy (HEAT BOOST) that does not seem to be going. Is the fool pump for this thing in the fire box or is it under the van? I swee the little tiny clear tube that feeds the box with fuel but the fuel is not moving when I turn on the heat boost.

I think instead of a fuel pump I have a fool pump. Someone is trying to trick me. (Not hard to do).

BULBASOR said:

WHAT???

Am I hearing this right? The REST gets it's heat from the ESPAR UNIT? Now I'm really confused.

Click to expand...

That is not what Sikwan said. He never mentioned the REST.

oH, I get it now, the AUX HEATER and the HEATER BOOSTER use the same ESPAR unit. Okay, now I get it. That makes sense to me.

It takes me a while to get it.

BULBASOR does not have the AUX HEATER, but does have the HEATER BOOSTER and the REST heater. The REST heater works just fine, but now that I understand what SIKWAN is saying I would no longer expect the ESPAR unit to work just because the REST is working.

I guess I got my hopes up. Oh Well.

argh, grrr.

Search ebay for coolant heaters. Somebody in Ontario had two Mikuni ? diesel fired heaters listed, about the same output as the Espars c/w wiring harness and seven day timer. The bid when I saw this was about $400. Thermo King is the Espars dealer and has the timer for around $170 and a switch for $30. These are for a stand alone heater and I 'm not sure if you can integrate it into the Sprinter.

Bob