Changing the cooland without airlocks

[JamesRGUK]

Whats the easiest way to do a complete cooling system fluid change without getting air locks in the radiatore etc...

I have had another one of my out-of-the-box ideas...

I was thinking of modifying a coolant reservoir cap (I have an old spare cap) with a hose fitting so that I could use attache a hose and use the tap preassure to force the water around the system and out of one of the water pump pipes as this is higher in the system than the radiator and so easier to eradicate air locks.

This way I could flush loads of water through the system before seeling it up and adding the coolant additive.

Just a thought, but can anyone see any major problems with this suggestion?

James

[NickT]

There is already a bleed bolt on the waterpump (, the one where you can substitute a spark plug in if you lose it)

I did this on mine when I changed the coolant hoses to silicon:

I removed top radiator hose & set interior heating to fully hot
i double checked heater valve is in open position
added gallon of coolant in
filled with water until it bled here
reattached hose
filled with water until it expelled from the water pump
screwed in bolt
filled reservoir
ran engine until warm
left overnight
double checked level

Any remaining air will be expelled via the self bleed kit (A MUST)

Even if you were to force the water in from the top down you can only get rid of air locks if there is a way of expelling the air from that point.

Good practise to flush out any rubbish from the pipes though. The hose on the cap sounds like a good idea. If you just undid one of the water pipes then you would probably only flush between the expansion tank and water pump itself. There are a couple of coolant flush points on the engine block although left hand side one is behind the cat and the right hand side one is behind the starter ! I left mine in place.

I did a similar thing by fitting a tyre valve in one and used it as a pressure tester/ leak finder once. The fault was with the cap itself but it did find a water pump leak. When I had my old VW Polo, the cooling system was silted up, I added washing up powder (4 scoops) to the old coolant and ran the car for a couple of days to de-sludge it before flushing it out. It worked quite well but I was a poor student at the time.

Good luck with it

NickT

ps Can I smoke some of your "out of the box" ideas enhancer
Kidding

[bozzzydmc]

There are engine blocks drainage points , one on each side, look like oil filler plugs, i removed these and flushed through with a hose pipe, its suprising how much crap is in there ...



Part 20 same on other side, just need a new copper washer on it when done.

[Dodgy Motor]

My tried and trusted method for bleeding all French designed cooling systems is :- buy one of those exceptionaly long funnels. usually conveluted. cut it down a bit to fit snug into the top of the header tank. you can then fill the funnel right up and this will give you an extra amount of pressure to bleed the coolant system , i think the force of a hose pipe might be a bit excessive and may lead to leaks you would not normaly have,, :?
Hope this helps