How often should systems be flushed?

Balfa

All those things that get flushed, like engine oil, transmission oil (preferably automatic, if you know!), cooling system, etc. How often should they be fushed as opposed to simply drained and refilled? In miles or months or "flush them every X refills" or whatever.

CJhaughey

I would be careful flushing anything other than relatively new(2-3) year old systems.
I flushed a Mk2 Golf Rad system once as per instructions stuck the hose in to the tank and was marvelling at the rusty water coming out, felt good and filled 'er up with coolant.
Jumped in and tore around next thing the car windscreen mists up and a funny smell starts wafting around, I had flushed out some sediment that was blocking a pinhole in the heater matrix.
learnt my lesson: If it aint broke don't fix it.

AMurphy

Balfa wrote:

All those things that get flushed, like engine oil, transmission oil (preferably automatic, if you know!), cooling system, etc. How often should they be fushed as opposed to simply drained and refilled? In miles or months or "flush them every X refills" or whatever.

Depends on the vehicle, age, setup, etc.

Engine oil, Never. Regular changes with a reasonable (name brand) oil is all it ever needs.
However, given hydraulic lifters stick, I found "Marvels Mystery Oil" excellent for unsticking them. So maybe some form of clensing additive just before an oil change. Once a year should be good enough.

Coolant; 3 years/30K should be good enough. Remember to remove all the flushing fluid thereafter, or it may eat seals (and other marine animals).

Power Steering Fluid; I just remove/siphon out as much oil as possible once per year and refill with the OEM fluid. (Found it un-stuck a sticking PS rack once).
Brake fluid, when you replace the pads, just bleed and push the pistons simultaneously, rather than pushing them and the old oil/sludge back.

ATF; Depends on the tranny. On a fully electronic clutch type using a synthetic ATF, may need to change every 15~20K, the clutches suffer a lot in those, so a flush/clean is good.

On a mechanical (Band type), 50~60K may be adequet.

Blitzkrieger

Everytime you drink Guinness. Ta-dum, tisccchhhh

CJhaughey wrote:

I would be careful flushing anything other than relatively new(2-3) year old systems.
If it aint broke don't fix it.

Ask your mechanic for your car. If your car uses thinner fluids it wouldn't need to be flushed as often. But I suppose just about everything is dot40 these days.....