12H-t/HJ61 coolant diagram for Webasto

[Christian]

Hi All.

I've searched high and low, including the original manuals I have, but it's impossible to find a diagram on the coolant system.

I have a Webasto Thermo 50, that I just took out for a service since the coolant pump died, and I'm uncertain that it was plumbed correctly...

The issue is that it's supposed to heat the cabin first, engine second, and does, the outlet is connected directly to the heater valve, the intake to the engine, but the flow might be opposed to the engine flow, if you get me, the lines crossed...

So, originally, does the flow exit the head and enter the heater, and return to the water pump, or vice versa?

Thanks, Christian

 

[sved]

Hi,

I have a eberspächer heater on the 2H .
Have installed it myself and the heatflow is supposed to go from the dieselheater outlet to the toyotaheater valve on the firewall.
This will heat up the interior first and second the engine.

The original toyota heaterhose (between engine and heatervalve on the firewall) should be connected to the dieselheater inlet.

That's the easiest flow setup.

There are more way's to setup the heaterflow,it all depends what you wants.

I changed the heatflow in that way that it will heat up the engine first and second the interior in wintertime.
In summertime i switch 2 manual valves so it will only heat up the engine. So the interior stays cool with the ventilatorfan.

 

[Christian]

Thanks Sved!

The issue I'm having is what is the original flow direction, I fear I might have it reversed, so the Webasto flows one way, and the engine the other, and this might have killed the Webasto flow pump.

So which way does the water leave the engine and enter the heater originally? Can anyone explain?

 

[sved]

it exits the head and enters the heater valve on the firewall. that is what i have and how is was originally.
then it exits the heater and flows back to the waterpump.

 

[Christian]

I found a picture of the hoses, and inserted some arrows, is this correct?

 

[sved]

Yes that is correct,looks the same like a 2H.

 

[Christian]

Yes that is correct,looks the same like a 2H.

Thanks!

 

[Christian]

Fixed! I got the new water pump for the Webasto yesterday, and the truck was warm and toasty this morning

 

[sved]

The cause for the dead pump,? Wrong connected heatflow like you suspected?
It's hard swimming against the current

 

[Christian]

I think so, but not entirely sure, as I'm not 100% on which way it was hooked up before , but it's correct now!
Btw amazing how a 12H-t without preheating just starts at minus 8 C...

 

[cruiserpilot]

Hi again, I just finished installing my Webasto TSL-17. I posted a link to the 60 series section. So far mine works okay. I took the coolant from the engine as above, and then returned it directly to heater control valve at the firewall, ( which isn't seen in the above photo ). You can see it in my pics. If you see I've done something wrong, let me know. I'm always worried I messed it up without knowing.

https://forum.ih8mud.com/60-series-wagons/794179-webasto-install-into-60-a.html

j

 

[Christian]

Hi Cruiserpilot

Looks like a clean install, I'v made a comment in your thread

 

[cruiserpilot]

Hi again. I am having a tough time here getting my truck to produce heat into the cabin. Since both of you guys have winter, can you provide me with trouble shooting help? I've got a Webasto installed, it works very well. AS in the above photo from Christian I have the correct engine lines flowing in the correct direction, but some reason my engine cools really quickly. Its been only about -6C here, so not really cold, but the air blowing into the cabin is luke warm at best. I even have a canvas cover over the entire grill. New thermostat, gasket and anti freeze tested fresh to -45 C. New heater core ( when I installed Webasto ) and everything flushed.

Tonight I opened the rad cap, jacked the front of the truck up until my bumper was 40" above the floor and let it run for a long time, put the rad cap back on and got it so it was
definitely warmed up. I lowered the truck, after it had cooled, removed the rad cap and checked to see it I had removed any air pocket.
I'm as certain as I can be that there is not any air pockets in the system.
The factory temp gauge works pretty well, and the indicator runs in the bottom 1/4 most of the time, will come up to just below half when
I'm driving it at speed on the highway. Still somewhat warm, but never hot air from the heater.

Any ideas to get the air temps up? I've heard stories of guys taking their coats off in 12Ht trucks in winter. I've got to put mine on.
Any help?

 

[sved]

Hi,do you get warm air in the cabin if the diesel heater runs for about 30-45min without starting the engine?

 

[Diesel Cruiserman]

Ya its so weird, you pull into my driveway and with in minutes the temp drops to the lower part of the gauge.. and the upper hose gets almost cold? Even after you installed a new thermostat with higher temp.....

 

[Christian]

hmmm... mine doesn't produce that much heat either, as a smoker I have my window open ½-1" most of the time, and I need the coat too.. I believe the 12H-t is the problem, it simply doesn't produce that much heat, not like the 2H... actually a sign of a better more fuel efficient design, new diesels needs extra heaters from the factory.

Of course it doesn't help that we plumbed a pump in, that acts as a flow stopper when the heater isn't running...

Do you have the aux heater under the seat or centre console plumbed in?

 

[sved]

Well i never have had a issue with heat into the cabin with the 2H combined with the eberspächer running or not.The HJ61 i have takes a lot loooonger time to warm up(no diesel heater in this truck).The 2H is warm after 5 KM but the 12H-t takes about 15 km to produce the same amount of heat in the cabin.
Turning the rear heater on or off doesn't change anything in the warming-up of both the 2H or the 12H-t in my case.

 

[cruiserpilot]

Hi,do you get warm air in the cabin if the diesel heater runs for about 30-45min without starting the engine?

It's about -2 here this morning, I started the webasto this morning 45 min ago, it's blowing warm air now.

Of course it doesn't help that we plumbed a pump in, that acts as a flow stopper when the heater isn't running...

Do you have the aux heater under the seat or centre console plumbed in?

The webasto should not have any effect on flow as it needs to flow through when not in use, and I do have the under seat heater, which
is flowing/blowing warm air - in fact seems to work very well,

I'm wondering if there is a flow conflict, but I'm certain that I have plumbing correct.
So in review: front standpipe from engine head forward flows aft along top of block in steel coolant line
to heater control switch on firewall, ( which I have now diverted to webasto, then continues on ) into main cabin heater.
:rear standpipe from engine head aft flows into under seat heater directly.
:both heater return lines flow into copper y-tube and return to engine via forward flow steel coolant line and into front lower
coolant manifold from water pump into lower rad hose.

After 1 hr 15 min, the whole system is pressurized, and hot from the webasto. The heater lines are all hot, and the lower rad hose is
firm and hot. Upper rad hose is warm, slightly pressurized (which I would expect as the thermostat hasn't opened )

So I'm going to take it for a drive, and see if I have removed all/any air in the system. This brings up a question I should have asked earlier:
Are 12H-T's prone to air pockets, or as I've been told, they are not and it shouldn't be a problem?

 

[cruiserpilot]

Well i never have had a issue with heat into the cabin with the 2H combined with the eberspächer running or not.The HJ61 i have takes a lot loooonger time to warm up(no diesel heater in this truck).The 2H is warm after 5 KM but the 12H-t takes about 15 km to produce the same amount of heat in the cabin.
Turning the rear heater on or off doesn't change anything in the warming-up of both the 2H or the 12H-t in my case.

You wrote this while I was in the shower, just heading out now. I agree, the rear heater does not seem to have any effect. I had a 2H before and it did have better heat.

Do you have canvas cover over radiator? If you do, how far is it from the radiator?

 

[sved]

No i don't have a radiator shutter.The original ''Toyota cold spec'' radiator shutter sits about 1-2 cm infront of the radiator.I had this on my 2H but removed it for installing a AC condensor.
Yes you installed the heater correctly.My 2H is connected in the same manner.
You could try to install it after the heater.So Cabin heater outlet -->webast inlet-->webast outlet-->return cold engine inlet.Heats up the engine first and second the interior.