Coolant system flush

Seven

Seven

Active Member
I am thinking of flushing through the coolant system and wondered if anyone had any hints or tips for this, or recommendations for a flushing product?

Do I need to use distilled water to flush it through to ensure no possibility of limescale or is regular tap water ok?

Are there any tips for ensuring I dont get any air locks in the system?

Thanks in advance.
 
First thing to ask is are you having over heating problems or do you want to flush the system as a precaution?
To flush take the rad cap off and undo the bottom radiator hose and let the coolant drop in one go, this will hopefully dump a lot of the silt sitting at the bottom of the rad. Now stick a hose in the top of the rad and flush it through until it runs clear. Push the bottom hose back on (don't bother tightening the jubilee clip for now) and re-fill the system and drop the water again, do this a few times until the water is clear, now you can think about adding a flushing product, I've always used Holts Radflush or Speedflush but there are other ones out there. Connect the bottom hose again and tighten the jubilee clip, half fill the system, add the flushing product and top the level up to about an inch below the radiator filler neck. Follow the instructions on the bottle then give the system a really good flush out with water before finally filling with coolant, make sure you use the old fashioned blue glycol based stuff.
Leave the heater valve open at all times, this should prevent any airlocks.
Good luck:)
 
Thanks very much Panky, very comprehensive.
No there have been no overheating issues, but after my trip back from picking it up I topped up with coolant, but have since read and realised that I used a standard coolant (green tinged) that probably has the OAT stuff in it, so I thought it probably a good idea to change this all and put in the blue stuff suitable for classic cars and as I was doing that I may as well flush the system for good measure!

Is it best to drop the bottom hose off rather than I think there is a drain tap (but can imagine this may be safer not to touch it in case of possible damage which is harder to rctify! :)
 
I forgot to double check, when you say leave the heater valve open do you mean pulling the heater control all the way out to have the heater running?
 
No need to have the fan running but open the valve on the top of the cylinder head full, it's a 90 degree turn open to off. I wouldn't try the drain tap as it could snap off and draining the coolant in one go by dropping the bottom hose draws a lot of crud out.
 
Thank you very much. I will try and identify the valve you mention on the cylinder head, when I am back with the van at the end of the week and post a picture to make sure I have found the right thing!
 
It's pretty obvious, a big brass tap sticking up on the left hand side of the head, proper valve:)
 
Also worth alternately connecting the hose to either end of the heater matrix and flushing it both ways until it runs clean both ways.
 
As promised attached is my checking photo! Could you possibly confirm it is the brass tap shown in the middle of the images? Is it currently in the ON position or does it need to be upright to be on?

Thanks very much for the help.

IMG_20170812_144018.jpg

IMG_20170812_143924.jpg
 
Yep that's the one, looks like it's closed. Be careful opening it, if it's stiff work it gently up and down until it's open.
 
You must log in or register to reply here.
Back
Top