Aux. coolant heater plumbing- where to? - PeachParts Mercedes-Benz Forum

coachgeo · #1 02-20-2009, 12:44 AM

ok.... this no start thing is driving me to desperate measures.

My 617 does not have a plug heater. I have a few coolant heaters like zero start I have collected. So.... where is the best place to install one of these. They are the no pump type so you have to have an upper and lower coolant (heater hose size) port ("T") to plumb them into so thermosyphon will work.

Where have you folk plumbed these into?

Thanx in advance.

Sorry for not searching first. Im a bit pissed at the moment and not feeling up to it. I know.... STUPID reason

compress ignite · #2 02-20-2009, 01:26 AM

Somewhere in the fog that's my mind I remember reading Long,Long ago...
That all MB's imported into the US, HAVE the block heater installed in one
of the "Freeze Plug" openings in the Block,You just have to get the Electrical
Cord for it.(The Original Owner had like 30-60-90 days from purchase to
request one [The Cord]from the dealer and it would be installed Free.)

So you may ONLY need the Cord.

Jeremy5848 · #3 02-20-2009, 01:32 AM

OM 617 engines did not all have a block heater installed at the factory. You could order one that way or you could get it installed free at the dealer in the first year of ownership. Later models (the OM603 engine, for example) had the block heater installed at the factory.

For those who do not wish to install a block heater (and the removal of the plug can be a problem), a lower radiator hose heater is the best alternative. I have one in my '617. It is not quite as efficient as a true block heater. To compensate, it is larger (600 Watts instead of 400). Heat circulates up into the block by convection and conduction.

Jeremy

coachgeo · #4 02-20-2009, 01:32 AM

my spare 300D has one but I am not prepared to pull a freeze plug under my present conditions

Butg.... if the plug/cord can be removed from it and put on my SD..... ohhhh will I be happy.

So the plug is suppose to be on the passenger side ... where on the block? I looked for one on my SD but there was no cord there.....

can I get to it easy from underneath?

coachgeo · #5 02-20-2009, 01:34 AM

ok.... so incase I do not have one in the block.

Back to my orginal question... since I have some generic Zero Start type coolant heaters.... where do you folk suggest I plumb them in.

Not interested in buying new lower radiator hose type since I have these others at my fingertips.

coachgeo · #6 02-20-2009, 05:07 AM

some links found by searching

http://www.peachparts.com/shopforum/showthread.php?t=85227&page=4

best one
http://www.peachparts.com/shopforum/showthread.php?t=238522

vstech · #7 02-20-2009, 08:59 AM

I would put the heater in the passenger side heater hose just downstream of the water pump. the "best one" pic filled thread, talks about a high wattage circulating heater... not likely what you have. just tee it in and you should be fine.

pizzachef · #8 02-20-2009, 09:10 AM

Ditto what VSTech said. And the other location to tap would be right by the oil filter (which feeds the cabin heater).

I mentioned this in the thread that you linked to (the 'best one'), is there anything inside the heater that would be harmed by coolant flowing through it the wrong way? If so you'd want to make sure that when the engine is running, the coolant is flowing through the heater in the correct direction, because you are for sure going to have some flow through the new lines.

But like vstech said, tap into the passenger side hose (returning from the cabin heater) downstream of the aux water pump. That way when the cabin heater is on, the aux pump isn't circulating coolant through your new heater lines.

There's too many references to 'heater' and 'pump' in this response

Let me know if something isn't clear. Good luck, I still like the idea of this type of heater, one day I'll probably go this route.

cmbdiesel · #9 02-20-2009, 09:51 AM

My 83 sd came with one installed. I don't know what lines were supposed to be there to begin with, but one hose (to the heater) is tee'd off the line from the overflow tank, the other(from the heater) runs up to a tee by the oil filter (one leg into the block, one leg through the firewall) Heater is mounted on the passenger side and cord is threaded through next to the headlamp.
Seems to work fine, at least until the tee breaks in the cold and you convect a couple gallons of coolant into your driveway, twice. My suggestion is to use brass tee's. I replaced the broken one with a quality NAPA part which lasted two days. The coolant cost more than the brass tee's.
If I get the flow of the system correctly, this arrangement puts heat into the block near the oil filter, and gets its cold source from the top of the radiator,
leaving the heater core out of the equation.

Bajaman · #10 02-20-2009, 10:05 AM

Look near the center of the block, just behind the turbo. You will likely find the block heater without a cord. You may have to do it by feel as you may not be able to see it with the exhaust manifold in place.

funola · #11 02-20-2009, 11:21 AM

Coach, forget the block heater for now. If your 617 is in good mechanical condition it should start with no problems at 39F. Have you taken compression readings and what are they? Do you have air in the fuel line? A very easy check for that is temporarily replace the cigar hose with a 5/16 clear pvc line. You should see a solid stream of fuel at all times. If you see no fuel or lots of bubbles, fix that first before trying anything else.