1999 BMW 328i (E46) – Coolant Hose Replacements Part 4

Hello and welcome to the fourth and final episode of the coolant hose replacements on the E46 328i.

So to start off the video, picking up where we left off last time, Greg goes ahead and starts mixing the coolant concentrate with distilled water to begin filling up the cooling system now that we have the hoses finished. As seen in the video, the proper OEM coolant for this car should have a vivid blue color versus the Green color of the coolant we dumped out of the system. It really is the nicest looking coolant I’ve ever seen, I wish we had transparent coolant pipes, if only so that we could see it! I should note here that yeah in a previous video, we had used green coolant out of a Mk.I VW Golf to fill the cooling system up after we lost nearly all of it when the upper rad hose had burst. But, the coolant that had exploded out of it at that time was also green, and we know this because the coolant had exploded onto absolutely everything in the engine bay (and it’s visible to some degree in that video). Anyway, whatever the previous owner had used for coolant in the car, it wasn’t the proper stuff. The old coolant was mixed improperly because it shouldn’t have froze up in temperatures <-10 as it was that day in early March. Either way, this debacle costed me about $800 in parts, potentially a shortened life for the radiator, thermostat, and likely head gasket as well. In the end though, a couple other pipes seemed to be in bad condition, so it was likely a good call to replace everything.

Now onto the elephant in the room, why didn’t we do the pipes under the manifold at the same time?!? The simple answer was stated in the video and that was that I hadn’t ordered a intake manifold gasket for the car, which was necessary if we were going to take it off. As well, an addition unspoken reason was that these two plastic pipes ended up costing about $200, and we had been hoping to not do them (at least for now), return them, and use that cash on the rear brake system that’s in need of repair before a safety, along with a camshaft sensor on the exhaust side that needs replaced. The hope was to get the car through a safety as quickly as possible, use the car for Summer 2021 (mainly to get it doing some miles to determine more thoroughly what condition its in), and then do some more (preventative) maintenance on it in Winter 2022 (VANOS Seals, new secondary air pump hose, aftermarket air box, new front brakes, new windshield washer reservoir etc…). Anyway, the car had other ideas, and after the car had ran perfectly for about a half an hour (condensed into about 5 minutes in the video), upon turning it off there was a large pop sound that I believe was the seal on one of the plastic pipes bursting. The reason I believe this to be the case will be revealed in an upcoming video where we actually remove the pipe in question and inspect it. While much of the suffering and pain we went through doing some of the hoses would be reduced by removing the intake manifold. As you’ll see in the next few videos, removing the manifold is not a fun or easy job.

Either way, the main takeaways from this video is the process of mixing the coolant 50/50 (though in warmer climates you could easily shift that ratio towards more distilled water), and the process of bleeding the cooling system. Neither task is difficult, but it is important that you don’t have air pockets in the cooling system as it can cause much suffering and agony with potential side effects being overheating the engine, blocking the heater core, and many more! Especially on these cars, which don’t have a well designed cooling system to begin with.

Anyways, enjoy the video! Drop a like, subscribe if you’re new, and drop a comment! We’re always open to suggestions on how to do stuff better, or just tell us about your E46 cooling system nightmares if you have one!