Coolant change/hose replacement

[Eric Hahl]

Hi all,

I'll be doing a coolant change and hose replacement on my 01' 330i step this weekend. I'm wondering what else I should replace as preventative maintenance while I'm in there. My car is almost a 75k miles.

Any suggestions?

Thanks,

Eric

[KNS]

I think the E46 has an improved waterpump over the older, failure prone ones but I would look into changing that and the thermostat.

[Jeron]

Unless you suspect a problem, I would leave the hoses until the radiator goes out. The plastic radiator necks last 80k-120k. You can get a full aluminum radiator for <$500 OEM are <$200.

I cant remember if the E46 has a plastic themo housing. If so see if they (the aftermarkets) make an aluminum thermo housing for the E46.

The pumps last a long time I don't know if I would change one before 100k, maybe even 150k.

I recommend doing the belts, plugs, ps fluid and reservior/filter, fuel filter, cabin filter, air filter, diff, tranny. But if you're changing hoses at 75k then you are are probably up to date on the rest.

[JOSERSE46]

PS Fluid and reservior/filter?? I didn't know the PS had a Filter, do you know of a good DIY article on this??

[tom busby]

I would advise leaving the hoses alone until the radiator or expansion tank goes out. I had a leaking radiator and the hoses were very difficult to get off. Then after I replaced the radiator the expansion tank had a leak that I believe developed in the process of removing the hoses. The hoses get very firmly stuck on and the expansion tank is very flimsy, much more so than the hoses. From this I conclude that the hoses last longer than the radiator and the expansion tank, which is contrary to my experience on other cars, so I can understand your intention to replace the hoses, but it might be inappropriate. I replaced the radiator and tank and all hoses on my 2001 325i at 75,000 miles.

[Jeron]

The p/s reservoir has filter built into it. You have to replace the reservoir (<$30) to replace the filter.

I did recently see a DIY on the p/s replacement but I cant remember where.

The most effective but painful method is replace the reservoir and fill with fresh fluid. Leave the inlet hose off and put it in a catch container. Have a partner turn the engine on to pump the fresh fluid from the reservoir through the system and into the catch container to flush the system. (I'll bet that wont take very long.) Then button it up, fill it, run it and check the level.

R&R on the reservoir is super easy. The crimp connections from the hard hoses to the flex hoses commonly leak so be gentle bending them around. If you go to all of that trouble use a good quality synthetic ATF or P/S fluid.