Cabin heat, 1.8T conversion, extra pump?

[rollercoaster]

Something thats not been quite right with my 1.8t conversion is the cabin heater,
its ok when I'm driving but at standstill, tickover, it just doesnt work!
Recently I had it looked at, new thermostat etc, still no good.
They told me that the best way forward might be installing an aftermarket pump.
I'm guessing that means an inline electric thing?

Has anyone had a similar experience?
Or any ideas to follow up on this?

This is in a TriStar, it also has an underseat heater plumbed in,
though it is possible to turn it off with a valve, which I did in case it helped.

This is enough of a problem that I mist up/get cold if its stuck in traffic.
The temp gauge is steady, low but steady.
Once the engine is operating normally the heater is fantastic.

[axeman]

hi tim 
i had the exact same issue in my doka with a 1.8 20v n/a, i also had the rear heater which had a slight effect depending on how open or closed the valve was, I assume that you have the later block which has a water pump driven by the cam shaft (which is what i had).

i chased this issue and could not resolve it, i found that if i raised the rev a little it would push the hot coolant to the heater matrix and heat the cab as expected, it was like the pump could not move enough coolant at idle, but never caused any over heating issues which i found puzzling. the temps were always with in spec and constant with the gauge and using vag.com

the reason a suspect the pump is that i have and do know know of this issue with the earlier style water pump which is the same as a jx.

would be interested to know if you resolve this. 

neil 

[rollercoaster]

True, I nearly posted this on your thread,
as it is good for you to think about..
Hope some great minds get to work on this,
otherwise I may fit a Propex!
Which I had planned to do..
Along with your backseat bed modification..

[rollercoaster]

So what do you think of the idea of an electric inline pump?
Is there any precedent for this in vehicles,
might there be one thats easily adapted to our needs?

[silverbullet]

A lot of "modern" cars use a seperate electric pump similar to the JX aux one to push coolant through their heaters.
I think it's more to do with coolant flow mis-matching, which is easier to fix with an on-demand dedicated pump just for the heater.
A bit like fresh air systems which dont naturally flow any air when the vehicle is in motion and have to rely on the fan to push air into the cabin.

[rollercoaster]

Heres a lot of words off the Samba on this:
https://www.thesamba.com/vw/forum/viewt ... eater+pump
No I havent read it all yet, it sounded simple at first and easy to do,
then various people try it and chip in with more problems and ideas,
I will wade through to the end and hope it all becomes clear and instructive.
I'm not alone with this problem at least!

[axeman]

Just read the through that lot and as you said there are a lot of opinions. Just to clarify on my doka the rad and the front heater core were replaced with hella ones the heater hoses were replaced with new and the front to backs were new ss. So everything was new. And i had the same issue.
Concussion was that the pump at idle was not man enough. The extra circulation pump I think is the ideal solution and was well documented in the samba thread. I would a better solution to the switching of the pump than just another switch drilled in to the dash.

[silverbullet]

Here's a thing: the SA 2.6 had a cambelt driven waterpump and I never had a cold heater problem. (there was a JX type aux pump but it didnt work)

This suggests that there is a flow problem with the 1.8T or the heater feed and/or return are poorly positioned relative to either each other or the radiator feed and return, when this engine is installed in a T3.

The SA had hoses that were very similar to the JX parts at a glance.

[silverbullet]

This is DSM (Duncan's) area of expertise.

[rollercoaster]

The extra circulation pump I think is the ideal solution and was well documented in the samba thread. I would a better solution to the switching of the pump than just another switch drilled in to the dash.

I was thinking the same,
and how hard would it be to trigger the pump by a thermostatic switch?
Keen to see what you do next and then I will be knocking at your door..

[DSM]

I agree that the performance is compromised at idle in cold weather as although the pump is more than adequate the  long pipe runs in parallel for the heater and radiator means the flow will take the easiest route and at low revs this is through the radiator. The donor vehicles have very short pipe runs in comparison and therefore not an issue. I've not bothered with an auxiliary pump yet I just raise the rpm to 1200. Any of the small Bosch pumps would be adequate but I've not thought about an automatic control method. I'll try out a few ideas later this year and report back.
As an afterthought it is preferable to fit the main water pump with metal blades as the plastic impellor is known to erode or even shed blades causing low flow. 
Still this is a massive improvement over my old Aircooled!

[Forden341]

The JX engine has an electric water pump that is hooked up to a relay and a thermal switch. I believe this was to draw heat from the fragile cylinder head after engine shut down. This would fit the heater circuit pipes perfectly. https://www.brickwerks.co.uk/auxilliary ... -1rib.html
Not sure about the thermal switch idea, I think I’d be inclined to fit it up the front near the heater control valve and control it with a simple relay and miroswitch on the heater switch lever so it would run on as soon as the lever was moved from the cold position.

[Cecil]

Maybe a switch operated by the accelerator pedal linkage to only operate the pump at idle and another switch in series ,fitted to the heater valve  so the pump does not pump against a closed valve. Obviously wired via an “ignition “ live . Having said that will the pump impede flow significantly while it is off?

[axeman]

One other consideration I am finding out as I go with the 1.8t engine install is that the heater input and out put are 19mm and 21mm on a longditudal set up. Would the increased presure and lack of flow be an issue when reducing the pipe size to 16mm to fit our vans potentially be an issue?

Neil

[DSM]

I looked back at my notes from 2013 when I decided to go 1.8T and there was a lot of discussion on the Samba about poor heater performance and many untried  ideas. I selected the Davies Craig EBP15 as the best solution however since then the price has escalated to around £80.00. The good news is it comes with a fitting kit and wiring loom plus adaptors for 19mm, 15mm and 12.5mm tubes. There is a Bosch 004 pump for less than £40.00 but it's pressure rating is 0.1 bar which is too low. The Bosch 002 pump at around £50.00 is ok but the flow rate is really too high.
   I ran mine in 19mm so if you use 16mm I would definitely fit the pump.
Hope this helps. D