No heat in toyota tdi conversion..any experience ?

8

8v-of-fury

Guest
I have no EGR, dont use the coolant plugs (although they are there) and the factory oil/water cooler is gone in favour of an aftermarket external cooler in front of the rad. Yes, the sandwich plate is thermostatic and does not open until the oil reaches 180F.
 

vanbcguy

Veteran Member
Joined
Feb 22, 2013
Location
Vancouver, BC
TDI
'93 Passat - AHU mTDI with GTB1756VK
I have gobs of heat on my M-TDI AHU. No coolant glow plugs, no EGR. Just the sandwich plate. I do seem to have a bit of an issue with my engine not fully warming up (at least as far as my gauge is concerned) but it makes HOT heat no problem, usually within 5-10 minutes of running. Accelerating briskly provides a surge of heat too.

The quality of the heater core will make a MASSIVE difference in the effectiveness of the heating system.
 
8

8v-of-fury

Guest
Well see heres the thing..

4 years ago when this was a gas car.. it made HEAT that was too hot. Could never have it on full coolant flow or it would be too hot and if be sweating to death.

I have had 2 diesel engines in their since each with worse heat..

1.6D first and then the 1 9TDI. Both of these got to run on the stock/original heater core that the gas engine made too hot. I just redid the entire cooling system this past january, and the heat hasn't gotten any better.

Yet my gfs mk2 1.6td and my bros mk1 1.9aaz make hot hot heat and fast too even with just idling.. now I know the older idi's are less efficient but THAT MUCH?? Lol

I want to believe I bought a "cheap" core.. but I doubt thats even possible.. cooper tubes and aluminum fins is pretty hard to screw up these days.
 
8

8v-of-fury

Guest
I think the rad and heater core were the same brand (as cheap as I could find) and the rad has no issues with heat transfer even with the temps getting over 40c this summer..
 
8

8v-of-fury

Guest
I dont get what could be the issue though..

Its entirely new, and the original everything that made great heat wth the gas engine made very little hearlt with both diesel engines.
 

geardriven

Well-known member
Joined
Jan 18, 2014
Location
alberta
TDI
ahu
There has to be a flow issue, your diagram is confusing but is your heater core inlet a t'd connection? The diagram looks like it is, and if this is true and runnin back to the water pump than problem solved as said earlier coolant will take the path of least resistance and flow straight back to the wp.Are both heater hoses hot? I see you have a flush t in the outlet, I am betting you can run the engine with the cap off it and it doesnt have alot of pressure/flow. Can you better describe/show the layout of your cooling system?

The heater core is basically a mini radiator, blower motor is its cooling fan, if you dont have flow of the 190* water it doesnt take long to cool that small amount off that the core holds especially if its half plugged. I agree with what others have said, compressed air wont do a thing when flushing any kind of radiator.
 

djtc

Veteran Member
Joined
Oct 29, 2013
Location
ottaws
TDI
mk4 golf tdi
Ill take a picture if the system tommorow and show you how its set up. Im starting to think that the routing is the problem but I wont rule out the other possibilities .
 

djtc

Veteran Member
Joined
Oct 29, 2013
Location
ottaws
TDI
mk4 golf tdi
Alright so I snapped a picture of the current system (dont mind the wiring mess) . Its a pretty simple system with 2 tees. If the heater valve closes it can re route straight back to the water pump.Im thinking that this may be the issue.I used this idea from another member on here that did a 1z swap into his 4runner.


NOTE: UPPER RAD PIPE BUNG HAS BEEN DELETED (VIEW PREVIOUS PICTURE)

If this is wrong and you guys have a better way to route the coolant hoses , let me know please!
 
Last edited:

Rockwell

Veteran Member
Joined
Nov 23, 2009
Location
Manchester, NH
TDI
2003 Jetta TDI (R.I.P.), 1.6TD Toyota pickup, 2011 BMW 335d, 1996 Passat TDI
Path of least resistance is down following red arrows, I can't see the coolant wanting to group through the core when the red arrow path is there
 
Last edited:

djtc

Veteran Member
Joined
Oct 29, 2013
Location
ottaws
TDI
mk4 golf tdi
so maybe run a reducer between the tees would create some resistance?? drop from 3/4 hose to 3/8 or 1/2? Even in the summer I never ran the hvac system on the cold side since it blew warm air anyways.No a/c in the truck so I just put the Windows down.
 

djtc

Veteran Member
Joined
Oct 29, 2013
Location
ottaws
TDI
mk4 golf tdi
or I may just cap off the 3rd tee end (red Arrow path) and just have the one route to see if thats the problem.
 

jimbote

Certified Volkswagen Nut
Joined
Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
TDI
Tacoma 4x4 converted to TDI
yeah .... temporarily eliminate the heater control valve too ... as rockwell stated the coolant needs to forced through the core or it will bypass it ... good luck and looking forward to the solution :)
 

djtc

Veteran Member
Joined
Oct 29, 2013
Location
ottaws
TDI
mk4 golf tdi
I wont have the time to do this till Thursday but I'll update it when its done.

Thanks guys
 

Rockwell

Veteran Member
Joined
Nov 23, 2009
Location
Manchester, NH
TDI
2003 Jetta TDI (R.I.P.), 1.6TD Toyota pickup, 2011 BMW 335d, 1996 Passat TDI
Just punch the red arrow hose lightly with a pair of vice grips
 

djtc

Veteran Member
Joined
Oct 29, 2013
Location
ottaws
TDI
mk4 golf tdi
Drove around with vice grip clamped on the hose with the red arrows....=still blows cold
 

djtc

Veteran Member
Joined
Oct 29, 2013
Location
ottaws
TDI
mk4 golf tdi
They are warm but last time I check they were not burning hot.

Coolant gauge shows a little under half point.

Not sure what or where the blend door is.. Are you talking about the heater valve? If so im not sure but ill try and bypass it.
 

jimbote

Certified Volkswagen Nut
Joined
Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
TDI
Tacoma 4x4 converted to TDI
inlet heater hose should be hot.... at least as hot as the engine...blend door is inside the hvac box inside the cab.... but if your heater hoses are not hot you need to find out why first...
 
8

8v-of-fury

Guest
My heatr core is too hot to leave your hand on.. yet has poor heat. (1984 jetta the hose end tank is accesible)

I sealed the box, and put weather stripping round the core to seal it to the box. Once the carr is at temp, lots of spirited driving or hills I have heat to defrost windows.. but normally it takes forever to get enough defrosting heat. I am using this cooling systems stock routing and all that.

I apologize for theead jacking.. just seems like the best spot for it with identical issues and all.
 

JaysinSpaceman

Veteran Member
Joined
Aug 5, 2008
Location
Skull County, Ca
TDI
Golf
They are warm but last time I check they were not burning hot.

Coolant gauge shows a little under half point.

Not sure what or where the blend door is.. Are you talking about the heater valve? If so im not sure but ill try and bypass it.
On my stock 1989 Toyota pickup with the 22r I have a broken lever on the heater controls that wont actuate the heater air door and I have to reach behind the heater on the passenger side floor and manually move the lever the cable is attached to (I should fix it but have bigger things to do) before I get any heat. This might be something to check on yours too.

That said, if the heater hoses are not getting hot (engine operating temp) then either your core is not seeing any coolant flow or your engine is not getting up to temperature due to a failed open thermostat. When you said above that the hoses are warm but not burning hot can you put your hand on the engine block or head and is it "burning hot"?

Jaysin
 

jimbote

Certified Volkswagen Nut
Joined
Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
TDI
Tacoma 4x4 converted to TDI


normal heat above.... coolant temp is displayed upper left of ultragauge (188.6 df) when under load the air coming from the vents actually gets within a few degrees of coolant temp ... it will literally run you out of the truck
 
Last edited:

djtc

Veteran Member
Joined
Oct 29, 2013
Location
ottaws
TDI
mk4 golf tdi
So! it ended up being the cable off of the blend door lever...I guess when I installed the vinyl flooring it unclipped the cable from the lever. So happy about this! Its nice and toasty but it wont burn you out like some of you have mentioned.
 

jimbote

Certified Volkswagen Nut
Joined
Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
TDI
Tacoma 4x4 converted to TDI
So! it ended up being the cable off of the blend door lever...I guess when I installed the vinyl flooring it unclipped the cable from the lever. So happy about this! Its nice and toasty but it wont burn you out like some of you have mentioned.
i wonder if some kind of restrictor placed in one of the coolant return lines would force more hot water through the core ?... it seems the early motors have too many return coolant paths .... the late motors don't give the coolant as many ways back to low pressure ...
 
8

8v-of-fury

Guest
I agree..

The mk1-3 system essentially has the small 5/8-3/4 heater core hoses going from the side of the head.. but on the front of the head they have the 1" bypass hose going down the front of the block to the low pressure side of the water pump.

Would the path of least resistance not be the larger shorter front hose? I am thinking I am thinking I am going to clamp that down a bit if not all the way. There is no chance this thing is going to over heat this winter.. All hot water can go through the core, should be fine.
 

JaysinSpaceman

Veteran Member
Joined
Aug 5, 2008
Location
Skull County, Ca
TDI
Golf
In my ahu/1z I have the heater core bypass for my coolant restricted to 3/8" or 7/16" (I can't remember for sure) and the heater core is 5/8". This way when the heater core valve is open the hot coolant wants to flow through the core. I get plenty-o-heat this way, It hasn't been super cold here yet but on cool mornings it would drive you out of the cab even with the driver's side window open all the way.

Jaysin
 

jimbote

Certified Volkswagen Nut
Joined
Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
TDI
Tacoma 4x4 converted to TDI
I agree..

The mk1-3 system essentially has the small 5/8-3/4 heater core hoses going from the side of the head.. but on the front of the head they have the 1" bypass hose going down the front of the block to the low pressure side of the water pump.

Would the path of least resistance not be the larger shorter front hose? I am thinking I am thinking I am going to clamp that down a bit if not all the way. There is no chance this thing is going to over heat this winter.. All hot water can go through the core, should be fine.
yep...I was just looking at the cooling system diagram and wondered why you couldn't eliminate that bypass completely .... maybe even run an ALH style water outlet at the rear of the head, possibly even enlarging the rear outlet port a bit to match the increased flow....it also seems I've seen some early water pump housings that had only one return.... has anyone else seen this? ... clamping it down slightly sounds like a good plan to get more heat.... let us know the result ...
 

djtc

Veteran Member
Joined
Oct 29, 2013
Location
ottaws
TDI
mk4 golf tdi
I might grab some 3/4 aluminum rod and drill a 3/8 hole in it for the bypass so it restricts it a little.
 

alphawerks

Veteran Member
Joined
May 21, 2010
Location
Ottawa Canada
TDI
many
Hey DJ,
The stock MK2 / 3 / 4 / ect VW colant systems don't have a valve to stop cooolant going through the heater core at all.
They just don't duct the air through the core if you don't want heat.

If I was you I would put the heater coolant valve you have on the bypass hose and leave the heater core full flow all the time. If you want heat use the valve to block the by pass and coolant will be forced to flow through the heater core only. If you don't want heat then open the valve and the coolant will travel through the lese restrictive bypass and minimise flow through the heater core.

Where are you usually mid-day? If it's the east end let me know.

Ryan
 
Top