1999 BMW 328i (E46) – Coolant Hose Replacements Part 1

Hey guys,

so we’re back on the 1999 BMW 328i and this time we’re kicking off a 4 part series in which Greg and I tackle the replacement of most of the coolant hoses on the car. As you may recall from this video, the upper radiator hose exploded on the car back in the winter. So we immediately decided to purchase some $700 CAD in replacement hoses, mainly so that we don’t have to worry about the system blowing itself up again for a little while. For this series of four videos, we didn’t remove the intake manifold to replace the plastic hoses that are underneath there for the simple reason being that we were lazy. We ended up replacing them a bit later for a reason that will be revealed in part 4 of this series. We also didn’t replace the thermostat or coolant expansion tank. The thermostat is still functional and at the time of filming, my limited budget dictated that I leave that for now if I was going to put the car on the road this summer. Secondly, the coolant expansion tank was likely replaced around the same time as the radiator by the previous owner, so we have no concerns about it at this point.

So in part 1 here, we’re mainly focused on draining out the cooling system and getting other parts such as the airbox out of the way so that we could figure out where all the hoses were. There was a lot of discussion between Greg and I while figuring things out that were cut from this video, mainly due to time constraints (as usual). But the main thing to note is that the Bentley Service Manual for this car isn’t the most helpful guide for how to complete this job. As well, draining the cooling system isn’t a very fun process either for a couple reasons (as seen in the video):

  1. The Engine Block coolant plug bolt is located in maybe the stupidest spot ever. Almost the entire suspension system on the car is below it, so when you remove the bolt to dump the coolant it goes literally everywhere.
  2. The system doesn’t drain very well. Greg had to blow into the system a few times to try and push more coolant out of the system. This shouldn’t really be necessary on a well designed system, but it is here. It actually still didn’t get all the green coolant out of the car. As later in Part 2, there’s still residual coolant in some of the hoses.

Anyway, let’s get on with the video shall we?!? Hope you enjoy it, and stay tuned for the next video!