Hi All,

Yet another question I am afraid.  It seems that coolant changes on the V6 are not the easiest and that you cannot drain the system completely.

Owing to a recent water pump change (by vaux) there is no hardly any antifreeze in the system – the water is only very slightly green and when putting some of the coolant in the freezer, it turned to slush!  Not good me thinks.

Anyway, I now need, obviously, to sort this out.  I have been reading on here and on Voxon about this and it would appear that many people have differing methods of changing the coolant.

Today, I went to Vaux to get some antifreeze but could only buy the longlife stuff which means I have to drain, flush and refill.  I do not really want to flush the block as, on the last car I did this, the HG then went!  Mind you, that was a totally neglected car and the coolant was basically rust!

In the Haynes manual, it states that you have to remove the thermostat to flush the coolant.  This would make sense to me, but in every thread on this subject, I cannot fit anyone removing the thermostat.  The Haynes also talks about pulling the coolant transfer pipe out of the thermostat housing – does this have to be done?  If I have got to get the thermostat out I may as well get a new one – how hard is it to get at?

Sorry to go on about this, but Haynes then says “undo the heater pipe and pour some antifreeze mixture in until it comes out of the pipe – then remake the connection”.  Again, I can find no evidence of anyone on here having done this

I have read about people draining and flushing 10 times to get their systems clean – I can not do this as it takes a day for the engine to become completely cold which would make the process take 10 days!

Finally, I like to use distilled water and it would appear that the system cannot be completely drained.  As I have to flush the old antifreeze (what little is there) it looks like I am reduced to hard tap water.

Does anyone have any step by step advice on the best way to tackle this?

Thanks in advance  and sorry for the length of the post and for revisiting what is perhaps an old topic.  At least I am not asking about oil or tyres though!

As he doesn't seem to have read this thread, send him a PM.

You will find him very helpful.

You do NOT have to drain your system just beacuse of your car having the older type antifreeze in it !
The Long life stuff ( orange ) will mix with the older blue/green antifreeze. Only it turns a crappy brownish color and the long life antifreeze will loose some of its long life properties !

If you drain the system using the drain tap, you will leave approx half the mixture in the system.


Long life antifreeze is the only stuff that Vx sell now , so if you by from them, its all you can have/get !

Just drain off what you can, mix up the new stuff 50/50 with water and replenish system ( slowly ) unitl full !
Next coolant system change do the same again, but this time you will be putting a greater percentage of long life in to the car, as the last change has mixed with the old stuff left in the system !

Failing that, and your sure you really want to get all the old stuff out, you'll need to flush etc , but there have been some people opposed to a flush and other saying its fine ! Just dont do it on a hot engine and flush through with cold water !!! Obvious why !!!

Mark

I changed the coolant from yellow/green to the orange/red last weekend. What I did was the following:

1. With engine cold, I drained the rad – very simple job, remove the filler cap and open the tap at the bottom of the rad then leave for 10 minutes.

2. Close the rad tap, fill with plain water, add one bottle of Holts rad clean. Note that the rad drain removes only around 5L of coolant, so you still have around 5L left in the engine block and heater matrix.

3. I did not disconnect the upper heater hose and primed the system with antifreeze as Haynes suggest. Instead I started the engine for a few minutes, then toped-up again until the expansion tank was full.

4. I the drove around for 15 minutes with the climate control on HI (and all the windows open… it was a hot day), making sure that the temp gauge peaked at its normal upper temp (around 97 degrees) and that the fans cut in. It is best to drive the car using low gears, because the water pump is mechanical and the higher engine revs will help circulate the coolant faster (around 3,500-4,000 rpm will do).

5. I let the engine cool, drained, then refilled with tap water. Drove around for 5 minutes just until normal working temperature has been reached. I then let the engine cool down, drained, refilled with tap water, and repeated this whole process once again including the 5 minute drive. By doing this twice with tap water I made sure that all that was left in the system was plain water – and I checked to see that clear water were coming out of the rad, i.e. no trace of the old yellow/green antifreeze. This double-flush also removed any traces of the Holts rad cleaner.

6. I then filled the system for the last time with Vx red antifreeze – and it took exactly one 5L container to get to the full mark, as I already had 5L of tap water in the system (remember that the rad drain only removes 5L). Been driving the car since and it behaves normal with no coolant lose.

Now a few notes about all this:

a. When I say I let the engine cool down, I only left it of a couple of hours. The engine does not have to be stone cold, just cold enough to prevent any damage to the block or heads as result of sudden temperature change. Incidentally, the water drained from the rad after two hours were lukewarm. And, to be on the safe side, I filled it with hot tap water (i.e. around 60-70 degrees) again to minimise the chance of temperature change damage.

b. As I said this was the quick way. Having said that, I am all in favour of ‘proper’ flush, including the removal of the stat and flushing the block etc. But the system seemed clean and the coolant was clear, so taking off the plenum and intake manifold to get to the stat seemed unjustified on this occasion.

c. As for the Holts rad cleaner, I don’t think it actually did much. I used it because it seemed sensible to give it a quick flush while I was at it, but to be honest if I had a sludge problem I would have gone for a heftier method using a commercial product (or just Plain Caustic Soda) and leave it in the system for much longer etc.

d. You mention using distilled water in the past – I used to do this on my old car until I was told off by a friend who is a Water Treatment Engineer (she specialises in desalination plants). Apparently distilled water is very active and will attack the metal to try and rob it of Iron and Magnesium atoms. Normal water already has a small amount of metal ions in it which make it chemically stable. What you really want is soft water, i.e. water that has low Calcium contents – and not distilled water. You can do any of the following (a) check your tap water with a very cheap fishtank Calcium testing kit availed from any pet shop, or (b) use bottled water – the Calcium content is listed on the label so choose one with low Calcium, or (c) boil the tap water once before using it, this will remove any access Calcium.

So in summary this was essentially a quick coolant swap that was achieved by diluting the coolant through repeatedly draining and re-filling the rad.

Hi Markjay

Thanks for that write up - I appreciate the effort involved!  That was exaclty what I was looking for - a guide by someone who has done a coolant change.

I will follow your steps by without the Rad Cleaner - my system looks pretty clean thankfully.

Thanks again for taking the time and I will post up how I get on.

Good write up markjay - now do it again with piccies so we can put in how2?

What picie...? There's a little tap at the bottom of the rad, and the expasion bottle cap at the top... I could take pics of those if you like.... Or do you want a picie of me driving the car at 3,500 rpm to circulate the coolant? 

OK, will get some picies... but as for the How2, we need to keep in mind that this is the NO-FLUSH version of the coolant change, which is OK for what it is, but we definitely recommend that if people have the time (and enegry..) then they should carry out a proper wash&flush.

TheBoy wrote on 02. Aug 2006 at 15:15:


Yes Sir!