coolant & heater core flow question - PeachParts Mercedes-Benz Forum

odie · #1 01-04-2005, 10:48 AM

300TD, 617 engine I think...

The heater hose that comes out of the head by the oil filter & IP pump...

Is this the out flow from the block and into the heater core? I want to use this to supply hot water for my WVO conversion.

HOWEVER, I disconnected the hose at the fire wall and ran the engine. No water flows out of this hose at idle. I have to rev the engine before any water will flow. as soon as I return to idle the water flow stops.

Is this normal?

tangofox007 · #2 01-04-2005, 11:15 AM

Quote:

Originally Posted by odie

300TD, 617 engine I think...

HOWEVER, I disconnected the hose at the fire wall and ran the engine. No water flows out of this hose at idle. I have to rev the engine before any water will flow. as soon as I return to idle the water flow stops.

Is this normal?

That is why the car has an aux water pump-to ensure flow at idle. But when you disconnect the hose at the block, flow through the heater plumbing is eliminated, and the aux pump will go dry. Assuming that it works, of course.

JimmyL · #3 01-04-2005, 12:33 PM

When I bought my jalopy wagon, in between the block and the firewall there was a manual water cutoff installed inline. Of course the knob was broken off, so I have never messed with it. However, wouldn't there need to be 2 valves to isolate the flow away from heater core,one on either side, or does it just go through the 1 hose. I don't see how flow could be created that way, or how blocking the flow would work the other way.
Make sense?
Is there a coolant flow diagram somewhere that I cant find.
Jimmy

**edit**
Would the aux pump be the other closed end of the heater core flow? I'm at office and can't go look at my wagon.

Palangi · #4 01-04-2005, 12:49 PM

On the turbo 617 the aux pump is down low on the passenger side, kinda towards the front. It may not be the same on earlier 617's with the servo type climate control though, in fact, I'm not even sure if that system has an aux pump or not.

JimmyL · #5 01-04-2005, 01:10 PM

Luckily I do not have the "Evil Climate Control Servo". My aux pump is passenger side next to wheel well. It also was/is unplugged. Does that close any type of valve by default when no power is applied. Is that the other end of heater core flow?
Questions, questions, questions...
Jimmy

Palangi · #6 01-04-2005, 01:13 PM

I have heard it said that if you're gonna disconnect it, you are better off to take it out and replace it with a hose, so as not to restrict the heater core flow at idle.

Edit: Must be a slow day at the toner mine ?

odie · #7 01-04-2005, 02:23 PM

I've bypassed the aux pump & heater valve because there can be no circulation without turning on the car heater. I don't always want heat inside the car, but always want heat in the fuel/WVO line.

I'm planning to put a "T" between the aux pump and water pump and run a line to another "T" just before the heater core inlet...

That way I will always have coolant flow for my heated fuel line above idle speeds and The car heater will still work too. either way, coolant from the head outlet hose must always go throught the hose-in-a-hose fuel line first, then either go back to the water pump or go through the heater core next.