Thoughts on re-routing coolant for faster warmups and warmer WVO.

[svein]

So, for a while I have been planning on re-routing a lot of my coolant lines in order to get faster warmups in the winter and more heat directed at the who system.

The first thing I am planning on doing is to re-route the return hose from the heater to the radiator to go back to the water pump to get faster warmup times and to keep the heat in the coolant system rather than letting it cool in the radiator. I know overheating is an issue on the 6.5 But I live in Norway and see most temperatures around the freezing point year around - and I don't really tow - so I am not too worried about over heating.

The next step is to re route the coolant. At the moment the wvo system is T-ed in in parallel with the heater core. I want to change its so it is in series after the heater core. That way, all the coolant will be forced thru the wvo system and more heat will be transferred to the wvo.

Another factor in the gameplay is that the brackets holding the heater lines to the rear heater has all fallen off, so I need to do something about it rather sooner than later

My machine shop guy has made me two three-way manifolds so I can split the 5/8" line going between heater core and water pump into three 3/8" lines. My wvo system is running 3/8" lines

Alternative 1 is to keep the rear heater hoses as is and split the wvo system as following:
- one line to the heat exchanger
-one line to the veg oil filter
-one line to the diesel filter and wvo tank

Alternative 2 is to cut into the rear heater hoses and make the rear heater a part of the 3way split:
-one line going to the rear heater
-one line to the wvo heat exchanger
-one line to all filters and wvo tank.

What is you guys thoughts about my plans? Is 3/8" too small for the rear heater? I use it very seldom, so I don't need that much heat to go back there.

Any thoughts are good thoughts!

Cheers

 

[FellowTraveler]

Have you considered a 'weather front' aka: grill cover I have always had great results on Northern trips during the winter using one.

Rear heater lines are 3/4" and a 1999 Burb w/dual HVAC the rear/front core flow is constant w/o water shut off valve so not using it matters not because the hot coolant is always present.

 

[Will L.]

Seems to me if you are running too cold, consider a radiator cover like he said above after verifying everything is working right. Less air flow through radiator is better aerodynamics and better mpg/ speed.

If you are constantly too cold: You need 160f minimum, 180f better, and 195f is best mpg. Be scared at 210f NEVER over 220f! Sorry for not converting to your better base 10 system. All that in mind:

Your heater hose circuit should always flow. Restricting it will cause cavitation which is damaging to multiple parts. That is why the heater valves are not just block off valves but are bypassing valves. So that the total is always 100% flow through that circuit and they should merge back to original locations.

Get AC Delco 195 thermostat(s) in there. Take the time to test them on the stove in a pot of water.
If you are trying to keep the heat in the engine do not use the brf fitting. Get a softer fanclutch or best would be the electro viscous ak diesel driver did and shared. Replace fanclutch and fan for an electric fan to completely stop air flow until needed. Even with the thermostats closed the fan and radiator remove heat from the antifreeze in it which pulls heat from the engine. Make sure you monitor transmission temperature. I’m sure you have a favorite temp sensor and gauge combo already for that fuel system. Another option is a smaller radiator.

Using term heat exchanger is confusing. The radiator, the 2 heater cores, and anything in the vegfuel system that uses heat from the engine cooling system is technically a heat exchanger. Can you please explain what the heat exchanger is in your system.

You are only thinking of the system working in parallel (using a Y or 3 way fitting and reduced hose sizes). Nope. Run it in series:
1. Most Volume to heat up is the tank, at least cared about is the rear heater core, so… Keep the rear heater core hose is the same size run them to the Tank first then to the heater core.
2. Use the front heater core line to the fuel filters, then the Front heater core. You will consume less heat to the filters leaving more heat to the front heater core to keep you warm.
Until I understand what that heat exchanger is I can’t factor it in. I am hoping that is the radiator at the front of the truck.

if you try all this and still cannot get enough heat out of the engine, get a Webasto fuel powered heater, running it off of the veg oil if possible to add heat to your heater cores and dedicate the engine to heating the fuels.

 

[svein]

Thanks so much for your ideas and thoughts!
Sorry my reply has taken me some time. Life wanted a word or two with me again. *sigh*

When I did my initial converting to veg oil I troubled with it for a long time, and thought the temps might be the issue, so I put quite some work into getting more heat into the system.

One of them was driving with a winter front, but it didn't really help me much.

I trew out my perfectly working 190f thermostats in exchange for 195f acdelco thermostats that opened around 185f. Out with them, in with some stant thermostats I got locally that now open around 193f iirc which works fine for me at the moment.

The heat exchanger I am referring to is a flat plate heat exchanger(FPHE) that I'm using to heat the veg oil with the coolant, after the veg oil has been heated in the tank and when passing trough the coolant heated fuel filter(VM2). I also have a heated fuel filter on the diesel line, to pre-heat the diesel a bit to reduce the chance of thermal shock to the IP.

When I started on the conversion about two years ago, I knew so little about cars in general. The learning curve has been steep! So what I did originally was to go to my local am car repair shop, and ask the head mechanic there where to tap in and out for the coolant. He pointed at two places, and I smiled and nodded and did just that. I am not 100% sure where the rear heater lines are in relation to this sketch, but at the moment I'm tapping a 3/4" hose (feed) and 5/8" hose (return) I think the 3/4 hose is between my existing "webasto" fuel heater and the heater core. Anyway - this is how it is now:


I talked with a friend of mine who also runs his truck on veg oil, who pointed me in the direction of putting the wvo equipment in series with the heater core rather than in parallel as it is now, to get more flow trough the veg oil system. I suppose that is exactly in the direction you are going, @Will L. , so I guess I'm on the right track here.

He also had the idea (and runs his truck) with returning the water from the heater core (and the wvo stuff) to the water pump directly, which gives him faster warm ups (and shorter time on diesel before switching over, which obviously is a goal).

Since my existing veg oil system is connected with 3/8" lines, I want to retain those, to be able to use what I have and do as little modifications as possible. I'm sure in a year or two, I´ve thought out a V2 of the system and will do bigger changes. To not reduce the flow in the lines, I have calculated that I would need to split the 5/8" line returning from the heater core to the radiator into three 3/8" lines, and my machine shop genius friend has almost finished making me these 3 to 1 splitters.

My original plan was to connect all the wvo stuff like this, leaving the hoses to the rear heater untouched:

I´ve noticed for a long time that the lines to the rear heater are full of damp when I'm driving in wet weather, so its no doubt that a lot of heat is lost there. Since I´ve now noticed that they needs to be taken care of somehow, I´ve been playing with the thought of doing my re-routing like this instead, giving the wvo system water that has never been trough the rear heater. It would indeed limit the flow to the rear heater quite a bit, but as I'm not using it very often, I'm not so bothered about less heat back there. So my new, questionable plan is like this:


Hope that makes my crazy thoughts a bit clearer!

Cheers,
Svein