Antifreez flush - while you are in there

[BimmerDob]

So looking at '03 4.6 with just under 70K miles. Time to do an antifreeze flush. Just did front outer CV boots. So with age (more than miles) I suspect rubber / plastic is past it's sell by date.

Not asking which antifreeze to use, many threads on that topic.

Plan to inspect antifreeze for any signs of water pump fin plastic and other tell tail signs.

Also plan to inspect all hoses (still original and getting on 11 years old).

X5 has been a low mileage ride most of its life, but now I am putting it to work towing to tracks.

So thinking preventive MTCE to reduce risk of getting stranded.

If I start down the refresh of cooling system, I will do all hoses, thermostat and I guess a water pump. Any other "cooling system" parts to consider "while I am in there".

Valley Pan?
Belts? Already replaced AC Belt.

[JCL]

Expansion tank and cap

[tmv]

also check the radiator, fan blade and fan clutch

[slowlanemcvane]

Auto transmission thermostat.

Water pump pulley.

Serpentine belt idler.

Belt tensioner pulley (no need to replace the entire tensioner).

[BimmerDob]

Thanks for the inputs.

Beyond visual inspect of Radiator and expansion tanks / caps for cracks / signs of leaks, any other inspection tips?

[admranger]

Check for Play in the WP bearing. It should spin smoothly, but not like a top. Same for idler pulleys.

[suss1173]

The water pump might has plenty of life left on it. However since your already there with the t-stat, I'd just replace it. Assuming you have the temp sensor on the lower hose replace that too. They often brake when taking them off.


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[g300d]

Definitely check the hoses.

I've got a 03 4.6is over here with about 25,000 miles on it that I had to replace a coolant hose on (burst hose). Replaced all the cooling system hoses while we were in. That was about 3 months ago.

Just recently replaced the expansion tank on that truck (pinhole leak). It's still at less than 30,000 miles I think.

[BimmerDob]

Thanks for all the inputs, will update as I progress.


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[Gregory891]

Check your pressure cap, consensus that moving to a 1.4 bar cap gives you quite sufficient cooling protection and less "stress" on the cooling system (compared to some caps at 2.0 bar).