Cooling PM Question

[borntodeal]

I own a 2002 530i and have had the radiator replaced in the past but the hoses were not changed.

The upper hose is leaking a tiny bit so I'll replace it.

In your experience, which hoses should I change as part of preventative maintenance and on what interval?

What hoses are easy to change and which are a bear? I'd prefer to replace everything that's easy if possible rather than wait for failure. Is that a sound plan and if so, can you suggest which hoses to change?

[CSMBlack-540i]

Unless you know for sure the age of each hose (based on date codes printed on each hose) replace them all at once for peace of mind. At 17 yrs, most are past end of life. Cost of each add'l hose is minimal too.

Otherwise, you'll find yourself chasing one hose after another and draining, refilling, and wasting coolant and possibly overheating the engine.

[E39 Newbie]

^^^^^^ Agreed. Replace them all.

The heater hoses can be difficult. It's hard to access the heater core nipples. The pipes that run under the intake manifold are very difficult unless you pull of the intake. If they're the same age you may as well bite the bullet and replace them, too. They get brittle over time.

[ULtm8drvnmchn]

FCP Euro sells a nice kit with everything youll need. Replace all the hoses, especially the hard plastic ones under the plenum. The plenum needs to be pulled, but its not a hard job, youll need new plenum gaskets also. Just need to take it slow and take pictures of the work as you go so you have references to where things go. In addition to hoses, you should replace the water pump, T-stat and housing, fan & fan clutch, over flow bottle & cap etc. Check both belts, check idler pulley operation, check water pump pulley....look at any vacuum hoses that might need to be replaced. Just be careful with all the plastic bits, there old and need to be handled with care. There are write ups for DIY on this.

[crazy4trains]

Search for e39 cooling system overhaul. If you haven't replaced it yet then do it now. Everything in the cooling system.