DIY-Cold weather, front heater solution

[goffoz]

I am not getting this How is a inline pump supposed to make any difference?
T3's comments on engine temps in the 200eds+ don't jive with my experience..
I have a 1.8T, new SS pipes,new Rad, rebuilt heater(old core. flushed) I have the lower temp T'stat on the engine...my scan guage shows consistently at 193F to 197F when driving in all conditions.
I have lots of heat, both front and rear heaters...admittedly were only getting down to the 30F's this week....but still, I have lots of heat.
How does this 12v pump alter anything?? seems to me, more flow is more cooling Is this thing Recircing the coolant in the heater loop "only"??
Be good to hear from SAH on the logic of this "add on"????

[jtrashy]

those of you with temps above 30' will not get it.
its has nothing to do with low engine temps. i always run 175-200' regardless of outside temps.
The issue is cool front heat in the 0-30' degree range at below 2500 rpm's. the pump we are using assists in drawing hot(running temp) coolant to the front heater core.
this writeup was for those with this issue. For those of you with great heat up front at all rpm's....awesome...dont waste your money.
for those of us with cold feet, it is a beautiful fix.

[bluefirefly]

[danfromsyr]

the aux pump only assists in circulating coolant that is already circulating but not necessarily with enough flow to provide ample heat
this promotes the improved circulation where it may be being bypassed coolant always follows a path of least resistance unless it's being assisted.

I'm curious if the pump can handle low voltages. because if you could hook it's feed up to the dash fan so that when the dash fan comes on the pump also turns on (and off) then there's not a 2nd switch to remember to turn on & off. but it would have to hook up to the wires afer the fan speed switch & resistors directly to the motor to work on all speeds.
maybe if you're using a relay (good idea anyways) then that wouldn't care if the trigger/switch voltage is reduced. maybe? just a thought.
currently my van has great heat, so much that i rarely have to even use the fan. and when I install my 1.8T swap this year I may change over to the 2.0l ABA coolant pump housing to retain the same coolant diagram as I currently have.
_________________

[Christopher Schimke]

Goffoz, my situation is seemingly very different than these other guys, yet in a way, I think they are related. In my case, I was having pretty severe engine cooling issues, both too cold and too hot depending on the situation. Even with all new cooling system components (radiator, water pump, thermostat, heater core, etc.) and with the hose routing checked and triple checked to ensure that it was correct (following Audi's cooling system routing), nothing would cure the problem.

Here is my theory: I think that the water pumps in these 1.8Ts are just barely creating enough flow at idle to keep up with demands. In some cases, they work well enough not to cause any problems at all (and maybe the presence or lack of a rear heater core has something to do with this). In other cases, they work well enough to keep the engine cool but there isn't enough reserve flow to push the coolant through the entire heating system adequately. I think in these cases, the majority of the coolant traveling through the heating system may be bypassing the front heater core and only traveling through the rear core or possibly even just bypassing most of the heating circuit and traveling mainly through the oil cooler circuit (path of least resistance). And then in extreme cases like mine, the pump just can't handle the demands at idle period.

I know for sure that my rear heater core was always warm and the oil cooler circuit was always very hot while my front core was stone cold. I also know that with roughly 35ºF ambient temps, the temperature difference between the main coolant hose coming right off of the engine and the coolant hose going into the radiator can be up to 90ºF (tested with IR thermometer on the hoses in the respective locations). This is before the coolant enters the radiator!

I'm still not 100% sure what all of this means and how it all relates and my theory above is just that, a theory. However, I do know that it is an issue that some experience and some don't. There are variables that may come into play as to how and why this happens to some and not others, like coolant hose size (early smaller diameter versus later larger diameter), specific hose routing, AEB versus AWP engines, possibly subtle differences in water flow based on brand, rear heater core versus no rear heater core, and maybe others. My system is the smaller diameter main coolant lines/hoses, rear heater core in place and open, AEB engine and the hoses routed exactly as Audi does in the A4.

Obviously what I mentioned in my first post in this thread about the heater core being plugged was not accurate. While my symptoms did improve, it wasn't enough as the ambient temps dropped. At the time that I installed the new core, our ambient temps were relatively mild (mid-40s to low 50s), but as the ambient temps dropped, so did the heat through the front heater core at idle. While the addition of the heater circuit booster pump did improve my heating through the front core, it did not solve my overall engine cooling issues as I had hoped (theory being that it would feed the thermostat with warm coolant to help stabilize the system...and since it's not part of this discussion, the answer to that can be found here: http://www.thesamba.com/vw/forum/viewtopic.php?t=538069&highlight=electric)
_________________
"Sometimes you have to build a box to think outside of." - Bruce (not Springsteen)

*Custom wheel hardware for Audi/VW, Porsche and Mercedes wheels - Urethane Suspension Bushings*
T3Technique.com or contact me at [email protected]

[Honuak]

I just got the pump in the mail. Very excited to get some heat up front. I have a subie 2.5 and a new heater core. I deleted the baffle/blocking plate when I installed the new core.
-when doing this job I should plug/crimp the heater hose to limit coolant leak? Did you end up re-bleeding the system when you were done?
I frikkin love thesamba, thanks!

[jtrashy]

yes plug/crimp the heater hose about 1-2" above cut to allow you to slide it on the pump without removing it again. remember to slide the clamp up prior to clamping so its ready to go.
I lost about a cup of antifreeze in the pump install without bleeding the system = no issues.

enjoy!

[Honuak]

I was going to plug it but thanks for pointing that out. Clamping back away a bit from where your working makes a lot more sense. What did you use to clamp it?
SAMBA!

[jtrashy]

vise grips work good, have plug ready just in case of a little leaking
a small Ratchet Bar Clamp would work good too

[Honuak]

I used vice grips with wood shims to protect the hose. Worked OK but I still lost enough (.5 gallon) that now I need to bleed the system due to poor planning on my part. On the upshot I invented a few new cuss words, the wife was impressed with my mastery of the English language. Now that I've done this once I could do it again in less than half the time. I'll bleed the system tonight and report back.
SAMBA!

[Honuak]

After bonging the van a bunch of times I think I have all the air out of the system. For anyone who is thinking of doing this there are a few things I found.
First thing is I had to use something to seal the 1/2 tube to the pipe to keep it from leaking. Be sure to secure the apparatus or it will fall over and spill coolant everywhere. I think I should have made the tube itself as tall as possible while still allowing fill, more hydraulic head that way. Plus that gives you more free-board when running the engine thereby preventing over flow of the tube. All of these things I learned the hard way.
So now that is all bleed ( I think) the temp stays steady just below middle, until I turn on the electric pump. Doing so creates a dramatic increase in heat temp (and smiles to my mug) but at the same time the temp needle drops, fast...all the way to cold. At highway speed the temp (at gauge) drops to the point where the heat is no hotter than before. If I shut off the pump it actually gets warmer...
So perhaps I have reversed coolant flow?
Or still some air in the system?
I have not blocked air flow at the inlets.
All in all a big learning experience - in progress.
I'm hoping some of you smart guys will weigh in. I don't want to crawl under and switch the hoses around on the electric pump but I will...
SAMBA SIEMPRE!

[Californio]

Another benefit to the aux pump. You stop for a while, someone goes into the store, and your heater will work great for 10 minutes or so without the engine running. The pump is circulating all those gallons of hot coolant through your heater core.

I am thinking cutting the flow to the rear heater would help also. There's supposed to be a flow restrictor but I don't have one and probably a lot of others don't either. ANyone mess with this?

[bluefirefly]

[Honuak]

Update. I drove today. There must have been just a little bit of air left in the system. The temp gauge is nice and steady now and the difference between pump on and pump off is dramatic. Very nice and hot when on, anemic and reminiscent of my air-cooled days when off. I did block off the fresh air intake on the front.
And another thing. 88 and later vans have dash heat. Im thinking through the dash vents that are fresh air only on my 87. Had I know this a year ago I would have tried to find an 88 and later heater box and put it in while I had the dash apart replacing the heater core.
I'm wondering if anyone has done this, and if so they had to sacrifice fresh air, change out controls etc...
SAMBA!

[jtrashy]

hey Honuak

glad it all worked out for you!!

how did you block your fresh air intake? i think I need to do that for my defroster.

I have an 87 and have dash heat, ASSuming you mean dash heat by the vents near the speakers.

[Honuak]

I used foil tape leftover from a construction project. Without it the air pressure would overcome the flapper and I would have a lot of air coming in, so much that even with the recirc pump it would make the air out of the vents cool.
Apparently vans produced in late 87 had dash heat. Mine only has heat to the windshield and below. The dash vents are fresh air only...with the fresh air intake taped off tho its just a little bit of air.

[jtrashy]

sorry...i should have worded my question better

im not sure where the fresh air intake is....is it around the front grill/radiator area or did you not the dash out and do it at the flaps?

[Honuak]

Take off the grill, right in the middle top, it should have a plastic grill on it. Fairly obvious when you look at it. Below link from classifieds for example. I taped over this on my van. http://www.thesamba.com/vw/classifieds/detail.php?id=1391043

[jtrashy]

sweet....covered it with tape and cardboard.

we'll see if it makes a difference with my defrost

thanks

[kuleinc]

Instead of taping the fresh air vents off, you could just flip the tab on the side of the dash vents and turn them off...
_________________
Check out our Our youtube channel: Https://www.youtube.com/channel/UC-EbskIxNm6SYzsq4ugG81A
http://www.thesamba.com/vw/forum/viewtopic.php?t=496946 1987 VW Vanagon Westfalia with 1.8T