Webasto pre heater plumbing - Land Rover Forums : Land Rover and Range Rover Forum
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post #1 of 2 (permalink) Old 01-03-2017, 11:25 AM Thread Starter
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Webasto pre heater plumbing

Also posted in the Defender section.

My name is Adam and I am new to the forum and as usual with newbies I have a question!
I am living in the UK but I am not getting much help with my question over here in the UK. I drive a 300Tdi 90 with 191,000 miles on the clock and still going reasonably strong!

I want to fit a Webasto or Eberspacher engine pre heater. Not a problem in itself , but nearly all of the information I can find says to plumb the pre heater directly into the inlet and outlet hoses of the heater matrix, at the point where the hoses exit the heater matrix. I personally don't think this will efficiently heat the engine block and cylinder head, as the Webasto pump would favour the short route into and out of the heater matrix. I believe the heat output of the Webasto should be plumbed into an area near the waterpump / front of the block and the retrieve of the Webasto can exit the output of the heater matrix. This I think would create a larger circuit that heats the entire engine.

I guess what I am asking you all is any of you with a 300Tdi and a Webasto, how is it plumbed in? and have you ever tested the temperature of the block and radiator after the pre heater has performed a full pre heat cycle on a cold day?

Apologies for the strung out description and question!


Landy204Ruger is offline  
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post #2 of 2 (permalink) Old 02-12-2017, 01:38 PM
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Hi Adam

I've just completed the installation of a Webasto Thermo Top C into a 300tdi Defender. It is a pre-heater that heats the block and the heater circuitl. The best place for the Thermo Top C is in the pipe run from the back of the cylinder head where it joins up with the heater matrix. This way, the Webasto heats up the engine block and the cabin heater water loop. Its difficult to install the Webasto without creating an air lock, so I turned a bit of ali bar to make a short pipe insert with a bleed point. It work very well and the air lock is removed in seconds.

Most people appear to have positioned the heater in place of the washer bottle which when has to be positioned elsewhere. I kept the bottle in its correct position and found a way to position the Webasto heater between the engine and the heater box. There is less than 1/2" of clearance, but that is sufficient. I had to make four steel straps to provide the necessary bracing and support but it work well and is solid as a rock.

With an external temperature of -5 degrees C, the Webasto heated up and block and 90 cab to a very comfortable position in between 15 and 20 minutes. I think it would be stretched to heat up a 110 to a similar level of comfort, so an air heater might be an alternative or additional option. We were drawn to the solution of a block pre-heater just to make starting easie ion winter. At -5 decrees C, and after a 20 minute pre-heat, we dont bother to wait for the glowplugs. the 300tdi springs into life on the first compression.

You will need to think about where to get the fuel from. The options are to break into the existing fuel lines or to install a new pick-up point in the tank. I would strongly advise the latter. For about 30, you can buy a simple kit that requires just a 6mm hole drilled into the existing tank sender unit. Troubleshooting becomes much easier when fuel supplies are independent.

The heater does take quite a bit of power from the battery in pre-heat mode, taking power for itself and also operating the cab blower motor. To avoid getting stranded with a flat battery, you need to limit the amount of preheat time to be no more than the subsequent drive time to allow the alternator time to replenish the battery. If your journeys are likely to be short as is the case for us, then you will need to fit an additional battery just for the Webasto. Use a leisure battery with a split-charge system to keep it topped up. And if that battery should go flat, you can always do a manual recharge.

The final thing to think about is how to control the pre-heater. My refurbished kit (420) with a 1-year guarantee came with an Eberspacher black rectangular control panel with a Mercedes logo on it. The text on the tiny display is minute which make it difficult to use and you can only create three programs. It does work well, but something else has to be better.

Come back if you want any more info.

B100 is offline  
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