~~Aux. Coolant Pump~~

[Clay]

This is the pump i have heard alot about. I know Skyski has one, is this the pump your using? Where did you mount it and how did you wire it in (strange looking plug on it)

http://www.partsgeek.com/catalog/1993/mercedes/300d/cooling_system/auxiliary_water_pump.html

[scooters2]

Clay, That is the pump Skiski and I am using currently. I Cut the plug off and wired it thru a relay directly off the battery, and a switched ignition wire. I have the pump in the return line that come up into degass bottle. Now each vehicle is different so you will have to adapt it to fit your hose setup. The pump has 1/2 inch fittings I ended up using some 5/8 hose(short) and 3/4 to 5/8 hose barbs to fit it up. The pump works great. Once the truck is up to temp my v3 stays on at idle when cold.
Now like you I am having some issues with v3 no coming on, or should I say the system runs but green light is flakey. I am trying to narrow it down, no luck as of yet new filters clean screen etc, I am leaning towards a relay problem or low voltage at switchover, stay tunned! Scooters

[Clay]

Clay, That is the pump Skiski and I am using currently. I Cut the plug off and wired it thru a relay directly off the battery, and a switched ignition wire. I have the pump in the return line that come up into degass bottle. Now each vehicle is different so you will have to adapt it to fit your hose setup. The pump has 1/2 inch fittings I ended up using some 5/8 hose(short) and 3/4 to 5/8 hose barbs to fit it up. The pump works great. Once the truck is up to temp my v3 stays on at idle when cold.
Now like you I am having some issues with v3 no coming on, or should I say the system runs but green light is flakey. I am trying to narrow it down, no luck as of yet new filters clean screen etc, I am leaning towards a relay problem or low voltage at switchover, stay tunned! Scooters

Return line to the degas bottle? Why wouldnt you put it directly inline with your VO loop? Like at the module? Would that starve the heater core? I was thinking about wiring it into the hot wire at the V3 pump so when the Fass pump comes on, the Bosch would come on too.

[HORSEMOVER]

The V3 with HOH is advertised as being tested to -20 with no issues. Do you really feel that an aux. pump is necessary? Only reason that I am asking is now I am concerned because if you are having issues this early into winter I may need to look at this as well. Are you sure that you don't have something else going on? It only makes sense that this would help but is it really necessary? There is a big spread between -20 and the 20's and 30's that some of us have been seeing. Curious to hear everyones thoughts because if I need to do this I am going to need to do it soon.

[Jack_Toepfer]

Jamie - I think you and I should wrap from the V3 forward as well, just as a precautionary measure. I haven't had any cold weather related problems yet, and we've seen 20s. -20s would be interesting though.

[HORSEMOVER]

Mine seemed to do fine for its first week of consistent 20s/30s too but I thought I noticed my light flicker a few times the other day pulling away from red lights with only 1,000 on the Donaldson. Clay's issues just have me thinking out loud. It has been fine ever since so maybe the system wasn't completely warmed up or something. Jack, have you done any additional wrapping yet?

[Clay]

The V3 with HOH is advertised as being tested to -20 with no issues. Do you really feel that an aux. pump is necessary? Only reason that I am asking is now I am concerned because if you are having issues this early into winter I may need to look at this as well. Are you sure that you don't have something else going on? It only makes sense that this would help but is it really necessary? There is a big spread between -20 and the 20's and 30's that some of us have been seeing. Curious to hear everyones thoughts because if I need to do this I am going to need to do it soon.

Go drive your truck and get it nice and hot and then feel all the coolant hose back to the tank...the return line from the tank should not be cool to the touch...mine is. As soon as the line exits my tank, it feels "luke warm" at best...the inlet to the tank takes a while to get hot too. The loop here has nothing feeding it as far as a pump, it relys on whatever circulation from the engine might provide and this is a BIG loop to feed. When your RPMS are up your water pump is pumping faster but at idle it almost stops pumping to this loop and my V3 will shut off. It didn't used to do that...i don't know what has changed but something has.

[scooters2]

Ok so maybe I phrased that wrong, it is inline with the return side of the v3 which runs up to tee below the degass bottle. I had thought of putting it near v3 but space would not allow for it to fit neatly and be at least partially protected from the elements. I wanted the pump to come on before fass pump does, reasoning behind that was to heat up v3 and tank pickup faster and at a more consistent rate. I have not had any problems with heater or defrost.
Jack and Horse, having gone through a winter already I have found that adding the pump has stopped the system from shutting down when you come to a stop, especially when getting off a highway etc. Ford did one thing right and that was the cooling system. short of a higher temp tstat which to date is not available on 6.0 this was the next best thing.

[Wilson]

FYI if you're looking for a good DC coolant pump, the 03/04 cobra intercooler pump is a good unit.

A few Ford dealers on the boards give 10% over cost on parts and if I find I need a pump I will get one of these.

But mine has been working solid so far down to 25*

I thought DFA tested HOH to much colder?

[HORSEMOVER]

I felt my lines on Friday and they were still pretty darn hot. Not as warm as they were in Summer but not luke warm like you are describing. That was after about an hour of driving which would make a difference I suspect. I will check them again with a shorter more average drive and see how hot they are. I am curious to see how you wire this up as it seems as if this could be a relatively inexpensive upgrade.

[Clay]

ok, and you put a swich in the truck to manually operate the pump?

[Clay]

It should be a piece of cake.
I will need to further inspect the coolant lines from the engine bay to the module i guess and make sure one of the hoses isnt partially collapsed or something. Again this issue didn't used to be so why its an issue now is a mystery but a collapsed line is all i can think of and i replaced all the lines behind the V3 but not the ones forward of the V3.

[Clay]

I felt my lines on Friday and they were still pretty darn hot.

Where were you feeling of the lines at...beginning of loop, middle, end?

[scooters2]

ok, and you put a switch in the truck to manually operate the pump?

Clay if this was directed to me, no I did not put a switch in. the relay is on key circuit. I have it run all year round. I was going to but never got around to it. Besides I have enough crap in my cab already. lol

To wilson and horse the systems have been tested to below zero, but this does not mean below zero at idle. Clay is on the money about coolant flow and flow at idle, its just not there. I can almost gaurantee that if you run your truck up to operating temp of v3 and then stop and idle for 5-10 minutes in sub 30 temps it will shut down and go on diesel.

[HORSEMOVER]

Where were you feeling of the lines at...beginning of loop, middle, end?

Right where they exit the tank - did you expect me to crawl under the rig and get all cold and dirty?