1999 BMW 328i (E46) – Coolant Hose Failure & Temporary Repairs

Hey guys, so one of the things that are talked about quite heavily in the E46 community is the terrible cooling system on these cars and how it’s a good idea to refresh it right after you buy it. This is because the system runs hotter than it should and isn’t particularly optimized. The radiator expansion tank is also prone to springing a leak and then braking but this had supposedly (along with the radiator) been replaced by the previous owner.  While we were certainly aware of this fact we had hoped to wait on doing anything with the cooling system for a little while (besides draining and refilling the coolant) in order to keep the project budget down, mainly because I don’t have the capital at this time to spend all the money on the parts it needs at once. So we took a risk on that and paid the price. While we aren’t 100% sure what caused the hose to essentially explode (as we weren’t around the car when it occurred, we had been leaving it idling to warm up the engine oil for the oil change we were originally going to do that morning) it happened which left us scrambling to temporarily fix the problem. Greg’s dad had a hypothesis that the radiator was frozen, and the aluminum shavings that come flying out of the radiator later seem to confirm that suspicion. This basically tells us that the coolant that had been in the car was not rated for cold temperatures, which is concerning as the car was driven in Ontario nearly it’s entire life and it gets colder in the winter than it was this day (it was originally a lease from Alberta).

It’s probably better to treat this video more as a vlog than anything as we didn’t know how to properly bleed the cooling system on this car at the time, there’s a bleeder screw you’re supposed to open). We also put improper coolant in, mainly talking about the green stuff, distilled water is always okay to put in a car. The previous owner was also running the wrong coolant as it was a pukey green color and it should be blue. While coolant comes in all different colors (my Cruze’s coolant is Orange for instance), it’s possible that this aftermarket coolant was incompatible with the car and slowly rotted away the hoses. Of course, these hoses certainly weren’t new but they didn’t look 23 years old either. Either way, our main priority was to just get the car temporarily fixed to make sure we didn’t blow the engine. Lucky for us, we seemed to have caught it before we damaged anything. We have since replaced all the hoses including the plastic ones under the intake manifold and put the proper blue coolant in the car. This was a big undertaking that we’ll have a large set of videos documenting that starting in July.

One thing that’s very very important to learn here, don’t hold off on fixing the cooling system, and a future video once I get this car safetied will go through all the things you should do on these old BMW’s as soon as you buy one. thank you for watching 🙂