PeachParts Mercedes-Benz Forum - Confused about WVO coolant circuit??

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Confused about WVO coolant circuit??

I am getting everything put together for my WVO system on my '81 240d....I got a homemade heated filter and heat exchanger, HIH and heated WVO tank.

The majority of the posts related to the routing of the coolant lines are for the 300d.

So my question is where do I tap in to SUPPLY the WVO coolant circuit?...and where do I return it to??

....I was thinking about Teeing into the line off the back of the head and then running it to the heated filter, heat exchanger, HIH and then to the WVO tank and then return to the line by the water pump.

Is this the correct way to route the coolant circuit to get the most heat??
Any suggestions would be much appreciated!

You are correct in where you start your flow (by the oil filter on top of the head) 5/8 Tee. And where you return the flow ( by the alternator) 3/4 Tee. Use Brass Tees.
The routing should be in the opposite direction as the fuel flow. (hot water one way, fuel the other way). That gives you the best heat transfer.
I'd go:
Filter
Heat exchanger
HIH
Tank
Back to return
Have Fun

...previously i was thinking you were suppose to Tee in off the water pump for your supply...would you not get good heat plumping it this way??

The hottest water comes out of the head on top of the engine.

Fattyman has his like mine.

NEED MORE HEAT!!

Well I just got everything plumped up yesterday and have been testing everything out....I will tell you I am a little disappointed w/ my WVO temps. Granted i do have a large tank(25 gal.) it was only about half full.....

I drove it to work today(36 miles one way) and my mechanical temp gauge for the WVO only showed 125* F after warming up...would not climb any higher.

Coming home the gauge didn't come up at all. Thinking may gauge may be faulty or installed in a poor location, I used a little no contact digital thermometer and my WVO lines read about 120-130* on the outside of the lines(double wall clear tubing)...

Tank read 110*

...on the other side I am having trouble making the switch from d2 to WVO...It acts like the WVO looses prime and i having to switch back and forth until its picks up and starts drawing the WVO...a couple time on the drive it started acting like it was starving for fuel and stalled.

...Could this be due to my lift pump not being able to keep up with the demand because the veggie is not up to temp.?

Need some help getting the bugs worked out...suggestions are welcome

Something is amiss, your oil should be getting hotter than that. I do not have a conversion in my 300TD (yet) but I used to have a 190D with a greasecar kit. The 190D had trouble getting up to temp if I was tooling around town slowly or it was a MN winter.

Solution...a second auxiliary coolant pump. Having a second pump that you can turn on and off with a switch will significantly speed up your switchover time, it'll get the coolant moving through your system much quicker and get it hotter.

There's probably a few more ways to get your system hotter but I'm not expert 617 wvo conversion expert yet...hope to be joining your ranks in a few months!

The 616 does not have an auxiliary coolant pump like the 617...if it would make a difference I could yank one off the 300d parts car and install it....

Yes I definitely think it will make a difference. I had two running on the 190d. It was pretty amazing the difference...if you were just driving below 50mph you would never get the temp to 80c in the winter, but once the extra pump was installed and turned on you could get it up to temp. On the freeway it would bring it to temp faster.

I was thinking about insulating my WVO tank...has anyone else done this??

I really would like to stick with coolant heat only, but ultimately if I need to go with an electric heater to get my temp. up I will...

Maybe I should add a FPHE to the system?....I was reluctant to use one because I have seen them leaking coolant into the WVO and destroy the IP.
I made a homemade heat exchanger by coiling some aluminum tubing around a coolant chamber made of 1 1/2" pipe then insulating it.

Also.....Where is everyone installing their WVO temp. sending unit? Before or after the splitter valve???