I've heard from various sources that the cooling systems on the V8's have a life of about 90K miles, and I've got 89K. Any recommendations on whether I should go ahead and replace, what I should replace, and a good parts source (don't want to replace with components that will fail in another 90K miles)? Thanks
Many places to look for answers, not the latest is http://540i6.com/probsfixes.html Speaking for myself - had the expansion tank failure (cracked 60 miles before the end of the warranty), followed by radiator failure a few months later (cracked), followed shortly (3 days) by viscous clutch failure (seized), and then, about a year later, had to replace the water pump at about 62k miles (bearing seal went south) - guess that extreme climate helped them all to fail prematurely. All that stuff is pretty DIYable. When I was performing the leak test last time, the heater valve assembly also leaked, but it doesn't leak under normal operating conditions, so I put off its replacement, though I know it is living on borrowed time. Original BMW E39 V8 radiator is said to be defective by design (metal core surrounded by plastic that always cracks), and there are full metal replacements that are better - look around for more detailed information, I didn't have a chance to get a better replacement so won't be able to say anything credible. When replacing hoses, replace everything that is plugged into them, in particular, the temperature sensor in the lower radiator hose - old sensor in a new hose *will* leak, even if it is as little as one year old. As usual, realoem.com is your friend.
For the amount you have to spend for the Zionville radiator setup, it's just not worth it IMO. I think it's $1200-$1400 for everything you need and you could replace OEM how many times before you reach that price point? Too many damn times for me to shell out that kinda money. As for when to replace, that depends on you. The average failure time isn't set in stone and can vary by tens of thousands of miles so idt you're gonna have any immediate problems (fingers crossed)... The radiator in my 2000 has been replaced twice, once by the PO and once by me. I've got at least another 50k before imminent failure (obvious leakage on the passenger side corner) but it only cost me a couple hundred bucks to replace. At the same time, I replaced the wp as a preventative measure and fortunately for me, the original was on the edge of failure so that worked out well. I also replaced my own expansion tank, not for the quoted $350+ but for a mere $70 and about 30-minutes of my time so what you choose to DIY could potentially save hundreds of dollars. Look for obvious signs of leakage, even the smallest little spots of dried coolant could mean complete failure is near so look carefully. Look around the corners, edges and hose connections as these seem to be the most common points of failure. Personally, if I didn't see any obvious signs of imminent failure, I'd wait until I could detect actual signs of leakage before replacing the radiator. Just my $0.02. GL...