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Adding pressurised overflow bottle to 300td radiator

Posted: Sat 14 Apr, 2018 3:13 pm
by EddieMurphy
Hi all,

I had a post recently about my water pump falling apart at 100kmh on my 81 diesel 300td w123 and destroying fan and radiator, it has been very difficult to find a replacement radiator in au to fit. I thought I had one sourced and was assured by parts place that it was the correct radiator but upon arrival it seems to be the w126 radiator which requires a pressurised overflow bottle. As it has no radiator cap and an extra hose fitting down the bottom. I can source an overflow from a w126 easily.

So my question is are there any reasons for me not to go this route of retro fitting a pressurised overflow bottle, are there any benefits and how can I be sure to have it at the correct height to ensure that the radiator fills to exactly the right amount and the overflow be accurate?

Also If I shouldn’t do this does anyone know where a radiator for my model can be sourced?

Re: Adding pressurised overflow bottle to 300td radiator

Posted: Sun 15 Apr, 2018 7:14 pm
by tsharkey
Hi Eddie,
I fitted the system you described to my 300TD. Get the reservoir and hoses that run between the reservoir and radiator from a W126 (The need some slight trimming as the W126 is bigger), or order a new set for a W123 from the sponsor. The existing main radiator hoses should fit OK. You can wire in the No Water warning switch if you want, otherwise leave it unplugged on the reservoir. You will need to make a bracket up to hold the reservoir in place, between the SLS oil bottle and top of the wheel arch.

Here is a picture of another of my wagons with this system
OM617A RHD Factory.JPG
I prefer this system as you can see at a glance the water level.