I don't know exactly how the MB cooling system works. Does the monovalve control flow through the heater core? Is it "off" blocking flow when the car is off? Will the Zerostart push fluid through the heater core circuit with the valve off? How does the Zerostart work? Is there an internal pump? The factory block heaters work pretty well as they heat the coolant directly too. In the work truck and the MB, 3-4hrs and the engines are warm to the touch in winter. Both provide almost instant heat too. How about you run both the Zerostart and the factory block heater. It would take a lot less time to heat up..... RT

At 20* F the Zerostart will bring the coolant up to about 170*F to 180*F in about 3 hrs and in our Jetta the oil will also be warm. :D There is no pump, but there is a thermostat. How it works is the same principle that causes hot air to rise and creats breezes. :D

hello all! i am new here and new to mercedes diesels as well. i have many questions but ive been searching and getting a lot of answers over the past few weeks. i think im ready to post a new thread wiht my questions but i would also like to know the answers to rwthomas1's questions regarding the zerostart heater (particularly if the heater can circulate coolant into the heater core or not). i just bought one of these for my 79 300TD and would like to also know if anyone has installed these, where they have mounted them, and where they have spliced into the coolant system. thank you very much for any response, i truely appreciate it!

It mounts to the low side of the coolant, in other words on the bottom hose. As I said above heat rises, and so will the hot water.

The coolant heater in the hose system is basic same as block heater, but is easier to install. It works on same principle as block heater, only it has a thermostat to control the amount of heat generated an electricty used for heating.

I just ordered a 1500W Zerostart from JC Whitney, along with the 'all mercedes' installation adapter. 1500W is higher than the usually recommended 1000W for our engine size, but what I've been hearing from the TDI folks is that its worth it to have the higher wattage, because it doesn't need to run as long. Just set up a heavy duty timer to turn it on half an hour before you have to leave, and its ready to go. I also do a lot of 'unplanned travel' since I'm a pretty scatterbrained guy, and I'd like something that can get things hot faster, so I can plug it in and be driving in less than an hour.

I've still got some questions about where the valves and and where in the system it should be installed, but I'll consult with the installation manual that it comes with, and do some more poking around and asking if I have to, I'm pretty confident that a good location can be found.

peace,
sam

Sam it should be installed in the lowest section of the hose you can.

im sorry oldnavy, but i also still dont know exactly where to put this thing either. it comes with a bunch of hose clamps and a "t" that fits in the hose that goes to the heater core. it says to tee into the lowest part of the bottom hose but it doesnt say which way the flow should go. it has 5/8" nipples on each end and has arrows indicating flow direction but the way i have it installed right now doesnt seem to be working. (i should have mentioned that i am not very experienced with this sort of thing and may need it "dumbed down"). sorry, i just cant quite picture it. and i was also wondering where people were mounting these if they already have them (ie-firewall, wheelwell, etc.). sorry for my ignorance, and thanks for any info!

Please remind me again
 

What's a block heater for? :sun_smile

Winter cometh.

Just for that, I'm gonna throw a coconut through your windshield.

Sorry if I seemed a little gruff, if the way you have it installed doesn't work just mount it the opposite direction. If I remember correctly the bottom hose has the flow toward the radiator and that would be the direction I would think you would point the arrow towards.

MMM, crispy critters. :D

very timely reactivation.....
 

i replaced the plug on my heater cord, plugged in Sat nite and when i got up sunday to go to church the engine was cold.

1. does the cord go bad while the heater is good?

2. should they be replaced in tandem like shocks?

Sounds like your block heater may have givenup the ghost. But before you dispare, make sure you have power on the extension cord you ran. Could be as simple as a popped breaker or switched outlet you were plugged into, or a socket that went bad.

sorry doc,
 

i should have mentioned that i have checked and tested successfully

1. the outlet lit up a bulb
2. the screw in adapter and 3 prong plug adapter worked in the house lamp
3. the outdoor cord was connected to and ran the table saw

I replaced a badly taped plug from the po. so i am still looking at the cord or heater. but with the other ideas hear maybe i don't need it.

whats the opinion here between block heaters and the hot water heaters?

I would unscrew the cord from the block heater and check it out. If it tests good buy just that part.