Talk Morgan Forums Thread Like Summary - Coolant system flush and antifreeze change.

Just getting ready to put my Mog to bed for over wintering. It's a plus 4 2010 car with a Duratec engine. When doing the checks I noticed that the header tank, a Ford item had started to show some brown sediment sticking to the upper surface of the vessel where the Radiator return pipe enters, That's one of the two small pipes that enters on the medial side at the top. This is a sure sign that the coolant has started to break down, so a coolant change is required. Now this will be the second time I will have changed my coolant ie. the third fill from new.

So I prepared to change out the fluid. Mine is filled with the Motal Ford product, the red stuff! so I ordered 5lt of that and 10lt of distilled water to do the job.
Unfortunately a lot of Morgans just don't get regular enough coolant changes or services as people assume that such low milages..... well the'll be ok won't they!
This is the first time my car has shown any sediment build up so I decided to do a cooling system flush as well and ordered 1lt of Prestone coolant system flush at the same time.

Now to the job in hand and really why I'm posting this. The modern Ford engined cars all seem to not drain down fully so this is the method of how I have worked out how to do the job without the chance of damaging anything.

I warm up the coolant a little, not enough to have the heating system at operating temperature or the thermostat open, say 3/4 minutes at idle, this tends to combine light particular matter into the solution as the water pump circulates it. This is done with the cabin heater on full and full fan, I then switch off the engine, make sure the rad is still cool and remove the header tank cap. Then under the car I open the drain cock and drain the fluid into a drain pan. Now the fluid drained out and looked like new. I tested it and it was within the required parameters, well it's five years old and needs to be changed anyway. Next I removed the header tank and flushed out the stubborn sediment which has a rubbery soft cheesy feel and is very sticky. OK, so that will mean that that sticky sediment from 15 years of coolant breakdown is coating a multitude of surfaces that I can't see.

So I decided I'm going to flush the system, It's a 10 lt capacity system but you can only manage to drain down about 6lts! Unless you start dismantling the cooling system, pulling hoses from everywhere, you will not get anymore out, especially as that tricky little heater matrix and pipes are holding the rest. Now in the old days you could pull hoses and pop off thermostat housings with gay abandon but these modern equivalents largely made out of plastic.... well that's not the way to go!
When you have drained as much as will come out, refill with tap water and run the engine. This time you do need to reach operating temperature and the themostat needs to open. When this has happened switch off and let the car cool down, when cool re-drain the system. Again you will get the 6lt's out. Next is the flush. Empty the 1lt bottle of Prestone flush into the header tank and top up with tap water, now run the engine for an hour and then let it cool down. Now here's why I choose Pestone coolant system flush. Not only is it possibly the best coolant cleaner in the world but it guarantee's to be non harmful or corrosive to any of your heating systems materials and it also offers a two stage option. You can stop here and drain it down then flush the system with plain water and refill with antifreeze or you can leave it in for 300 miles and then flush and drain it out if the system needs a heavy clean. However I have found over the years that a slightly different method works for me the best!
So back to switching off after running for an hour. I then leave it in overnight and in the morning I start the car up. reach operating temperature with the heater matrix and fan on full and after about ten minutes I shut the heater selector fully off until the engine thermostat opens and hot coolant enters the radiator. I let it run until the stat closes and I then open the heater matrix fully. after a few minutes I switch the engine off and wait for it to cool enough to drain it down.

Wait until you see just what comes out and the colour of it. You will also see by the associated foaming that it has cleaned the system. You will now have to go through the flushing process probably three more times ( remove all evidence of foaming ) and on the last flush when you are happy the drain off is showing clean, top up this time with distilled water. You want to remove as much of the tap water as you can. Now drain down for the last time. you will still have the retained roughly 4 Lt's, 2 being tap water mixed with distilled water.

Checking the drain cock is tightened and you have no leaks start to fill the system with concentrated antifreeze, You will get about 4 3/4 Lt in to the level mark, if you are struggling here start the engine and it will be drawn in. I mixed the last 1/4Lt with an equal part of distilled water as a top up should I need it!

Couple of points:

I'm not sure my system holds the full 10Lt's I think anomalies like pipe lengths will vary the capacity so don't panic if it all won't go in!

If you still have the original Radiator, I do and my car runs at a perfect 90' c ,which I'm happy with. A lot of owners who have alloy replacements are finding it hard to achieve this and are always running cool. The original has the modern trend of plastic end tanks and on the lower left of the radiator it has a drain cock with a cross in it to undo etc. Many say not to touch this drain cock as its vulnerable to failure, This is not true! It is a perfectly functioning pet cock and has an 'O' ring seal fitted so only needs lightly tightening. To undo and tighten use a large slotted screwdriver not a cross head variant. Pulling at hoses and pushing to refit them is far more likely to damage these radiators than using a perfectly designed drain off!

Deejay,

Think it might look orangey because the new coolant is shifting the deposits in the engine and they were red coloured from the OAT coolant. Mine didn't show a lot of sediment but just small deposit areas in two places in the header tank. As I said when I initially drained the old coolant out it looked perfect, right colour, perfectly clear. It was only through experience that I knew I must have some level of yuk within the cooling system to allow the deposits to reach the header tank. What surprised me was just how much muck the flush shifted when to all intense and purpose it would to most look like it was a clean system.


Dave.

Is your roadster running with the green antifreeze? It has a lot of silicates in it and its these that might be causing your deposits. Another thought is are you mixing your antifreeze with tap water. If you are in a hard waster area it might be calcium deposits.

Yes I use a refractometer such as picture link below to confirm coolant freezing point in each vehicle before winter.

Yes Djay, I worked out when doing all the flushes that I could only refill through the header tank to a maximum of 4 3/4 Lt with the thermostat closed so when I was satisfied that the whole system was full of clean water I drained down the system ( as much as I could) and refilled with neat concentrate at just under 5 Lt. The last 1/4 Lt I mixed in the bottle 50/50 with water. I then started the car and took it to thermostat open temp where after cooling I was able to top the system to the correct level on the header tank using the remaining mix.. After a couple of days of running I then checked the coolant concentration and it was spot on for a 50/50 mix strength.
So the final fluid used in the system consisted of just under 5 Lt of concentrate and 5Lt of distilled water. This was effectively mixed by the water pump within the engine when running and allowed me to obtain the correct mixture strength.

Cast aluminium and 17.5mm at the barb.




Worth a try for £4.83 delivered.