Found a pool of water under the car last week, just before first event of year. So feared worst, but tracked down quickly to a split hose - the small water hose from the right hand side of the header tank. It was split right at the end so presumed OK to just shorten and reattach. But on looking at hose I struggled to see a hole! Stuck a drill bit down it wondering if a blockage at end. it wasn't. I presumed it is not meant to be micro bore and needed changing. But as it disappears forward down to top of the water pump I decided it could wait till after the sprint. Along grounds of its been like that for a while so another day wont hurt. refixed it, and came second pipped at post by 1/10 sec. still good start to season. Now back to sort that hose. You need to take off a fair bit for access. But an easy job. I took off power steering surround and the mounting plate so it was loose, the fuel hoses on right hand side and fuel block to move out of way and water pump was clearly visable. So a nice new hose installed with new clips and we are sorted. I presume this has been building up. and is an age thing, so may be worth a check on others as not a big job. other side, left hand was fine, but i replaced that as well whilst there. Pics of old one below. Image Unavailable, Please Login Image Unavailable, Please Login
Yes, similar problem on 355's, Dave Helms sells a superior replacement. Or if you use oem, just replace it with every major service.
Better to use a silicon hose(it holds up better under hi temp). Regular rubber hose can't stand up to the steam heat that is in those 2 hoses. There isn't any water in the upper area of the hoses, where they connect to the tank. This is a self bleeding mechanism on the 355 and steam that is in there simply destroys the inside, ie; they kind of rot away from the inside.
I did this recently as well, resplaced every single coolant hose with Silicone. Well worth it I think.
