You noticed after you'd bought it? And tbh it's a subject of some debate some never run them and others think it'll boil over as soon as you remove it. My RR doesn't have one now and I've noticed that other than it being much quieter and maybe a tiny bit more grunt no temp difference at all. If your towing a 3.5 load every day I'd fit one to be safe but my RR doesn't tow anything nor will it and I don't off road her.
iv'e taken mine back off and its hell of a lot quiter and as littlewill said a little bit more pulling power i also think its a little bit better on fuel
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