Need to do a full cooling system flush and I have read the guides on here which are great and I know personal preference will come into play but which system flush do you consider is best? Especially if the system has not been done for a while and I suspect its gummed up. I know Holts and Wynns do a flush and I have even read somewhere that someone used a crushed dishwasher tablet!!! but it wasn't on a Jaguar.
So any recommendations would be very welcome

 

The best flush is plain distilled or deionised water. Simply drain, refill, bring up to temp and drain again until the previous antifreeze has been removed. Twice is normally sufficient.

Richard

 

Thanks Richard for your reply not sure if just distilled or ionised water on its on will shift any stubborn deposits but willing to give it a go

 

It's up to you but my go to product is Thermocure. Made by the same people as Evapo-Rust if you have used that? It works the same way by chelation so it's not acid or alkali.
Nice and gentle too. I usually run it for a week or so to get a number of heating and cooling cycles on the engine.
Thermocure

Easy to find as it's widely distributed.
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Thank you for that clubairth1 I have used Evapo-rust a few years ago on another car and it did do a good job but I didn't know that I could run it as long as you did to to get a cleaner flush

 

Yes that's one of the nice things about Thermocure (Not EvapoRust) is there is no hurry to remove it because like Evaporust it does not attack or remove anything metal. Only rust as it's converted to a water soluble Iron compound that can be flushed away. Like EvapoRust it is a bit expensive but you don't use it very often so I think it's worth the price.

Now you might get surprised as I have found these late model all Aluminum engines just don't have the muck and filth in the cooling systems like the old Iron block engines. I was doing a 2014 5.0L Ford Coyote engine and ran ThermoCure for a week and It came out just about as clean as when it went in.
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I ended up using basic prestone radiator solution from the part store. My heater was not producing satisfactory heat anymore, and after the usual suspects proved ok, I did a heater core flush (basic garden hose procedure, nothing fancy). Even using cold water (and leaving the solution in the core for the amount of time prescribed on the container), the heat produced by the core was night and day. Heater produced warm air after about a mile of driving in freezing temperature. My unsubstantiated theory is that over time, dexcool coats the cooling system somehow, and a proper cleaner is required to break this barrier once in a while to promote/restore proper heat transfer.

Best of luck, keep us posted.

 

Thanks for that info and that is Amazing regarding the 5.0L Ford Coyote engine maybe the way it is ported helps so that the coolant flows through better. Either way that is impressive!!

 

Thank you for your input regarding the use of Prestone.. I have seen this mentioned somewhere before but I did wonder if it might be a bit too harsh.Although I do agree that the Dexcool probably does leave some kind of coating behind which you can see inside the header tank and on the caps and I don't think that is a good thing either.

 

Would be curious if there is some procedure to obtain a more complete block drain, a seal bolt somewhere. The routing of the radiator hoses precludes the radiator drain itself from being a good place to empty the system.
One thing which would be nice would be a Fumoto Style Drain **** for the radiator. Its spigot is in exactly the wrong place.

 

Never tried it myself, but apparently the freeze plugs are available for this purpose as well. Unfortunately, they are located above some obstruction and make just as much of a mess.

 

thanks, but no thanks.
I only knock those out when rebuilding an engine and when they leak.
Doing that with the block in the car is a recipe for a lot of hurt.

 

The AJ8 block drain plug is just aft of the left motor mount. (17mm hex plug)

 

Thanks, do not think that it applies in my case, however good to know.
I will look there though...

 

I tried to flush AJV8 cooling systems with only radiator and hose disconnect but it takes too many drain/fill cycles without draining the block.