To flush or not to flush...that is the question

[sprinternut]

I have recently lavished an outrageous sum of money on my beloved 1997 Sprinter 310 on essential repairs, one of which was head gasket replacement.

My question is fairly evident by the post title, but prior to me putting in new anti freeze/inhibitor, would it be beneficial to flush the system with a proprietary cleaner like holts system flush or similar, considering that the head has been removed? (well actually, it's a reconditioned head, thanks to the numptys who damaged my original one while refitting it, but I wont go there!)

As usual all advice considered an appreciated....

 

[turbopete]

the way i see it, a flush can do no harm and may in fact be beneficial as there may be oil or other contaminants or sludge etc in the radiator etc! id tend to flush it as failure to do so could potentially lead to overheating etc and flushing costs very little. when refilling, make sure you use a good quality anti freeze of the correct type for alloy heads.

 

[oigle]

Back in the 70s when I was serving my time, reverse flushing was common, with a hose pipe. We would take the thermostat out first and insert the hose from the top rad hose into the block.

Best do the block first, excluding the rad, or crap from the block could lodge in the rad.

Exactly right. Don't forget to turn on the heater so it can flush too.

 

[kth286]

and only use Merc coolant solution with treated water.

It is ph neutral product and will prevent excess erosion of the various metals/rubbers in your system building up more sludge.

Over the years on the forums I reckon it is the guys that use the merc products that have the least problems with coolant circuit items.

The cynical amongst us feel the Merc product us just the same in a different bottle with a higher cost.

I have read how much research they do and the coolant is specified and designed to their own spec.

So I may be paying a pound or two extra but it is my insurance policy and I am still on my original radiator at 168,000 miles.

 

[oigle]

We always left the heater valves closed until later in the flush, in case we clogged up the heater matrix with shi* from the block.

The heater matrix is very fine with narrower passages than the rad.

Not sure on the Mercedes set up today on water in/out and whether it is closed when dash controls are in the off position.

My past experience is with cable controlled valves. Thing of the past.

Yes, I'm talking from days of yesteryear too. I think most modern vehicles have the water circulating through the heater matrix constantly and just divert air to do the heating inside the car. Not sure on that one.

 

[Mr Teddy Bear]

I used the VAG Approved Purple stuff it's available from Euro & GSF.