The TEFBA certainly works if you have junk floating around in your cooling system. I used to have one on my RRC and I cleaned it out once a month and caught quite a lot of alum fragments from going into the radiator.
For this reason I put one on my P38, but to my surprise, it was pretty clear each time I checked it.
I have since, in the last few months, done a major overhaul - heads off, machined, new head gaskets, new radiator etc , so i don't expect it will have much to do now either.
It's really one of those "peace of mind" things - and with the P38, I'll take any of those that I can get.
2011 Range Rover Sport SDV6 Autobiography
2007 Range Rover Sport TDV6
2004 Freelander TD4 SE
1997 Range Rover 4.6 HSE
1994 Range Rover Vogue
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