Flush cooling system?

[10G]

Heading away for 4 weeks solo into the outback in June/July so not too hot.

Don't think the Patrol has ever had its cooling system flushed. It's never overheated and I don't think I've ever seen it hit 94 degrees.

It's a 2013 Y61 CRD and has been regularly serviced.

Just wondering if I should flush it out as a wise preventative measure or do cooling systems these days not need to be touched unless they play up??????

Thanks for any advice.

[mudski]

Coolant should be changed every 2 years, about. So if its never been done. Its overdue. But. Will you be opening a can of worms doing it so close to your trip? If your going to do it, I would be doing it now. Also grab a small tube of Silver seal or similar and leave it in the tool box just incase you spring a leak.

[10G]

I've got 6 weeks until we leave and I drive the Patrol every day, so I reckon if something gonna give, it'll give before we leave.

As i live where the water is really calcified I was thinking of filling it with distilled water. Am I being over cautious or wise????

[Plasnart]

I've got 6 weeks until we leave and I drive the Patrol every day, so I reckon if something gonna give, it'll give before we leave.

As i live where the water is really calcified I was thinking of filling it with distilled water. Am I being over cautious or wise????

Wise mate. The manual says 50/50 coolant and distilled water.

[10G]

Is just a drain and a bit of a flush through with the hose all that's needed or do I need to go a bit more indepth?

[the evil twin]

If you want a Coolant flush only - Drain it, flush the Rad for a minute or two, fill with tap water, run it for 5 minutes with Heater on Hot, drain it, flush it, fill with Coolant at manuf specs (some coolant is premixed some you dilute yourself), burp the system, top up if needed.

[10G]

Thanks ET.

Are those radiator flush formulas worth using or are they just snake oil?

I also read that the engine block has a drain plug on it, but it can be tricky to get it to reseal again properly. Is it worth taking that plug out? It's literally been decades since I've flushed a radiator, all I can remember is that I always get wet.

Thanks again.

[the evil twin]

IMHO only and others may disagree...

If your only changing coolant then dump it, flush it, fill it and leave all the drain plugs etc etc alone and don't bother with a descaling agent etc.

If you want it descaled, block drained, rad core cleaned etc etc then I would head off to the Rad Man of your choice and get "the works" done.

[4bye4]

Thanks ET.

Are those radiator flush formulas worth using or are they just snake oil?

I also read that the engine block has a drain plug on it, but it can be tricky to get it to reseal again properly. Is it worth taking that plug out? It's literally been decades since I've flushed a radiator, all I can remember is that I always get wet.

Thanks again.
I would agree with ET, that if you want a full radiator flush get a pro to do it. Potential problem with off the shelf flushes is the possibility that some of the loosened gunk gets stick somwhere and restricts the flow unless the flush is done correctly. If your cooling is ok and the fluid is clean, no rust just do a coolant change. If there is rust or gunk in the system, get it professionally done.

[10G]

Yep, I reckon I agree, thanks guys the words of wisdom. I have 2 new radiator hoses that I bought about 10 months ago as spares. Think I might fit them at the same time & keep the oldies as spares.

[10G]

OK, so I had a shot this today.

I'm confused. I'm only getting around 5-6 litres out of the radiator, the manual says it holds around 13-15 litres.

Firstly, I did a cold flush, just removed the drain plug out of the bottom of the radiator, removed the caps off the radiator and the pressurised rear tank thing. Put an oil pan under it that said it held 16 litres. It got about half filled.

Secondly, replaced both radiator hoses, nothing came out of them. Filled it up with water from the tap, had the heater on flat out & engine running. Filled up radiator and the pressurised tank as needed. Went for a drive, got it up to 87. Got home and drained it. Only about 5-6 litres out again (about half the 10 litre bucket I used).

The water is getting clearer with each flush which is good. Here's a thing. When I undo the radiator cap, the water is hot. When I undo the drain plug underneath, the water is cold, however hot water does eventually come out.

Where's the missing 10 litres?

Am I doing something wrong?

Thanks for any help.

[0-TJ-0]

In the engine? I had this issue and i had to take the thermostat out to drain it properly.

[10G]

Ug. Just been reading that you should never use tap water. I did know that, but I thought it'd be OK for flushing???????

I'm consistantly getting the same amount of water out every time I flush so I hope all that bloody tap water is coming out.

Re thermostat, I was hoping that by getting the engine temp up to normal op temp, 87, the thermostat would be open and all the water would drain through it, maybe that just doesn't happen????

[10G]

I'm letting it drain overnight with the front of the car pointing down, maybe it'll trickle out over night?????

[0-TJ-0]

I reckon as soon as the water drops away from it the thermostat would cool enough for it to close. Dunno mate I'm no expert.

I just used the hose to flush mine, let it drain then filled it with the good stuff after. Might not be ideal but I'm not I'm not paying the premium to flush it with the bottled stuff.

[10G]

I reckon as soon as the water drops away from it the thermostat would cool enough for it to close. Dunno mate I'm no expert.

I just used the hose to flush mine, let it drain then filled it with the good stuff after. Might not be ideal but I'm not I'm not paying the premium to flush it with the bottled stuff.

That all sounds fair enough to me.

So when you removed the thermostat, did you get alot more water out?

[0-TJ-0]

Yeah and it allowed me to stick a hose in one end and flush it through some what. I think there's a drain bung on the block somewhere that will drain a bit more again but I've never used it. Perhaps it might be worth finding that instead?

Edit: On a td42 just for clarity sake.. but on my cruisers in the past I used to have to take the thermostats out to flush them properly as well.

[10G]

Morning after. I reckon about 2-3 litres leaked out overnight. Going to look at removing the thermostat today.

Was reading my Haynes manual this morning. In their 'flushing the cooling system' section, they mention to get the garden hose, stick it in the radiator hose and turn on the tap! So maybe using tap water to flush with is OK????

They also mentioned that the thermo housing has a drain plug and that it can take 30 mins for all the water to drain.

[0-TJ-0]

I need to get one of those manuals..

Yeah have a look and see whats easiest. With the stat out you can push a fair bit of water through to get a good flush though. Just be careful with the bolts. I've read other people having issues with them seizing and snapping?

[Bidja]

Morning after. I reckon about 2-3 litres leaked out overnight. Going to look at removing the thermostat today.

Was reading my Haynes manual this morning. In their 'flushing the cooling system' section, they mention to get the garden hose, stick it in the radiator hose and turn on the tap! So maybe using tap water to flush with is OK????

They also mentioned that the thermo housing has a drain plug and that it can take 30 mins for all the water to drain.

No need to remove thermostat housing(may not be straight fwd), but would enable full flush thru sys.
Remaining water/coolant still in engine block. Drain via eng block plug.
Understand that eng block drain plug is below oil filter and to get to it remove the oil filter drain into tray/bucket. Need to seal drain plug when finished_Read that"threebond grey sag type silicone" works and can pick it up at repco or most other automotive stores.


If using same coolant type you can just drain radiator via bottom plug, then close off and fill with distilled water, warm up and operate full heater to circulate(few minutes) then drain via radiator plug again. Do it a few times. Must say I always only use genuine coolant and have good tank water so that is what I use to do the job. For me, even if changing coolant types this is what I would do anyway.

Had ADRAD radiator joint in ACT do an A/C job for me few yrs ago and got them to do radiator / sys flush, think they just back flushed sys with tap/hose water back thru top heater hose at firewall(heater turned on). Pretty good tap water though.

[10G]

Well this job is done and dusted.

I read the manual and found there's a drain plug in the thermostat housing. I found this, but saw it was inbetween the radiator and the thermostat, so no point in removing it. Went & looked at removing the thermostat, but what I could see looked like nothing in any photos of other ZD30 thermo housings I saw on Google etc, it looked totally different, that combined with the risk of snapping and/or seized bolts and how bloody hard it was going to be get it off, I decided to leave it.

In the end I ran 2 lots of demineralised wiater through the radiator and everything else and drained it all out, the last drain I got 9 litres out, so I was happy enough with that.

Everything I read said the cooling system holds 14 litres, so 14 - 9 = 5 litres of coolant left inside. So I put in about 4 litres of coolant concentrate and 4 litres of demineralised water and left the spare litre for when it all settled down. Topping up today with demineralised water.

Drove today for an hour on the way to work and everything looked fine temperature wise.

Things I learnt, next time I'll get the pro's to do it thoroughly. Pouring the water/coolant in slowly works much better than flooding it in, I found I hardly needed to do any 'burping' of the system. Lots about the cooling system.

Thanks everyone for the help.

[mudnut]

I used the reverse air pressure of the shop vac to blow out the last couple of litres of our Falcon. Had to be careful not to completely seal up the vac hose so it didn't over pressurise the system. Got a fair bit of gunk out too.