Mopar Muscle Association UK

I'm wanting to flush my system out as it could do with being renewed. Has anyone any experience with Preston coolant/antifreeze. It states it can be used on its own or mixed with any other type. I want to flush mine out and start again. I picked up two bottles 8ltr of this, that should give me a 50/50 mix of antifreeze and water?

Use loads of that Prestone that stuff all the time, good gear.

Yank service folk used to bring loads of it over with them, I guess they thought that 'lil 'ol Engerland wouldn't have antifreeze, oil and brake fluid on the shelf anyhow, when they got posted back home they still had it, so rather than cart it all back to the states again, they used to give it to a worthy recipient .... me

Thanks Mike. I picked these up in GSF in town. The guy at the counter recommended it on my needs, I bought on a whim, but wanted to double check before putting it in.

Next dumb question is, I've never flushed an engine etc before, can I pull the return from the heater core to the engine at the engine, with the rad cap off, run the engine with fresh water going in the rad till the return from the core runs clear. Then add the antifreeze and then pipe back on. In my mind this will flush all the engine/rad/heater core and prevent air locks?

Or is that a stupid idea?

Hi,
You should just disconnect the bottom hose, let it drain out (all over your garage floor after realising that the 200ml cup wasn't big enough).

Then Bananarama! outside, run the hose through the top of the radiator to push all the crap out.

You can buy additives to do this.
I've heard of people running a dish washer tablet in the car for 10 minutes then dropping the water also.

Then top it up after reconnecting the hose.

run the engine but leave the rad cap off and switch off/top up as the car will need to bleed the air in the system.

Will that get it all out of the block and heater core as well as the radiator?

I shouldn't have lots of gunk in there as the rad and engine are only 6000ish miles old, the heater core is original though.

I had a bash at this today, I undid the valve at the bottom of the radiator to let the water out, filled it with water and ran for a minute or so and drained again. Kept doing that till water was clear(ish). I then added 8ltr of the Preston stuff and that filled it up! I was expecting it to be about 12quarts? Around 15ltr? I have run the car and kept taking the rad cap off to check and it's not dropped any. I've had it out for a run and it's been fine, temp has sat consistent and the heater has been hot. Feeling the engine everything feels like it's getting hot, the rad/block/hoses.

I'm wondering if I didn't get all the old water out?

Its difficult to get everything flushed. In order to get a full coolant circuit the thermostat has to be opened. The best way is to drain the old stuff, flush what you can with a hose through the rad etc. Then refill with water and run engine up to temp (to get stat opened), then let it cool down and drain off again. Then finally refill with the good stuff. This will give you the best chance of getting all the muck out.
You can always run a coolant flush additive for a bit before initially draining the old stuff out if you feel the need.
If you want to go further, you need to unbolt the stat housing and flush through there, or run without the stat for a while.
Sounds like your car is ok though, if the heaters working and all the hoses are getting hot, you should be fine.

Thanks, yeah my concern is that I've gotten all the air out before I start using the car for longer journeys

unless the water jackets in heads are higher than the top of the radiator I think you will be fine. any air quickly migrates to the thermostat and burps through when it opens.

Dave

Thanks Dave, I'll have a check when I'm next in the garage, I'm sure the top of rad is higher than heads.