Cooling system flush

[eoptio]

Hi all

planning to replace the radiator, various hoses and the coolant this weekend (weather permitting...). I wondered if it is neccesary to do a system flush with Holts radiator flush or similar as well given that I am replacing the radiator? Or not required (would save quite a lot time as not having to let cool down and drain the system several times)?

Thanks

K

[mikeonb4c]

Hi all

planning to replace the radiator, various hoses and the coolant this weekend (weather permitting...). I wondered if it is neccesary to do a system flush with Holts radiator flush or similar as well given that I am replacing the radiator? Or not required (would save quite a lot time as not having to let cool down and drain the system several times)?

Thanks

K

I'm not top dog on these things but personally if I was fitting a new radiator I'd reckon the main reason for using Holts radflush just flew west so woudn't bother. Maybe wait and see what others say

[mister munkey]

Recently had a Back Flush done, along with a couple of new hoses. Assume they used some kind of flushing agent but the results are quite remarkable. It seems to remove a majority of the crap in the system to improve coolant flow.

It now reaches a temp where the heaters actually work sooner & holds a cooler running temp when it gets going.

Give it a go, nowt to lose!!

[missfixit70]

What about the all the tiny channels etc inside the engine? These are just as likely to be blocked as the rad, it's called radflush, but it flushes the whole system, don't forget you've also got 2 other rads in the system in the form of the heater matrixes. IMO it's a bit shortsighted to assume by fitting a new rad, that solves all potential blockage situations. Get it flushed properly while you're at it (thermostat out with rubber sealing ring left in place, quicker to bleed & all the system is open, meaning the chemical gets everywhere & it'seasier to make sure it's all flushed out afterwards), then you know you've done everything possible to ensure it's working ok. I assume you're replacing the thermostat as well, if you haven't already. If that isn't working, you're wasting your time with the rest of it, as the engine will cook as soon as any load is put on it, easy job to do & only costs a few quid.

[eoptio]

Hi

thanks for replies all, yes am replacing the thermostat as well. Sounds like it's best to flush it so will see how it goes this weekend

K

[missfixit70]

you know it makes sense

[mister munkey]

The one thing that concerned me was after top hose popping at Silverdale last year - followed by a legendary rescue by BDC & DBO on a Sunday, the old hose had a fairly thick crispy layer of rusty stuff in it. Its fairly safe to assume that the rest of the system had the same gunge in too.

I had it in the back of my mind that after getting the whole lot cleaned out that it might be prone to further leakage - as the crust can - in effect - block any potential popping points. A bit like a Morris Minor wing just held together by rust. Take the rust away & the wing falls off.

Fifteen hundred miles later though - its not used a drop of coolant.

Happy days.

[mikeonb4c]

What about the all the tiny channels etc inside the engine? These are just as likely to be blocked as the rad, it's called radflush, but it flushes the whole system, don't forget you've also got 2 other rads in the system in the form of the heater matrixes. IMO it's a bit shortsighted to assume by fitting a new rad, that solves all potential blockage situations. Get it flushed properly while you're at it (thermostat out with rubber sealing ring left in place, quicker to bleed & all the system is open, meaning the chemical gets everywhere & it'seasier to make sure it's all flushed out afterwards), then you know you've done everything possible to ensure it's working ok. I assume you're replacing the thermostat as well, if you haven't already. If that isn't working, you're wasting your time with the rest of it, as the engine will cook as soon as any load is put on it, easy job to do & only costs a few quid.

She's the boss

Just do it

But seriously, at the grave risk of answering back, my assumption was that the little pipes in the engine block probably got scourged more than the radiator which - holding a volume of water and because I imagine the pumping pressure gets diffused through its core pipes, ended up behaving a bit like a sediment tank. This impression seemed to be supported by the stories of people replacing their radiators and getting a massive improvement in engine cooling. But I'm not a trained (automotive) engineer so my assumptions are not worth so much. It does seem to make sense to go the extra mile though for peace of mind.

I hada little google for radflush and quickly found a blog where an owner said:

1. whenever I buy a 'new' car I give it a full service. This includes the cooling system. I flush out the coolant with water and then clean out the system with Holts Radflush. I put each part of the Radflush in with plain water for 1 day (usually to work and back = 50 miles). After using the second part of the Radflush treatment I flush copiously with water and then replace the coolant with new. (see below for my coolant mix).

2. Every two years I flush the coolant out with water and treat the system for 1 day with Holts Speedflush. Flush again and replenish coolant.

My own mix is any longlife antifreeze (currently using Halfords Advanced Protection Antifreeze)at 25% with de-ionised water and half a bottle of Red Line Water Wetter.

Bearing in mind that not all the coolant can be drained out of some systems - after flushing (with the hose) I fill the system with deionised water and run till the thermostat is open and then for a further 5 minutes at idle. I then drain the system as much as possible. I then put in the measured amount of antifreeze (not pre-mixed) to give the required concentration. I then finish filling with deionised water.

I only use the water wetter because I have a petrol turbo (the turbo is water cooled). Otherwise I've never bothered.

It is a lot of effort, but I've never had any problems with internal corrosion and since I intend to keep my current car for many years I believe the effort to be worth it.

...which I found quite interesting. Must try that myself (I'll be using 50% antifreeze though I think as recommended, though some on BF think it superfluous in our climate).

[bongoben]

Antifreeze is made up of 2 parts, usually ethylene glycol and a
corrosion inhibitor package. Ethylene glycol can remain stable
for 5 years or more but corrosion inhibitors deplete over time
and use. If you use a 25% ratio of antifreeze then you are only
using half the recommended quantity of inhibitors which will
deplete very quickly and render the protection virtually useless.

Mazda recommend a ratio of 50% "Long Life" antifreeze, but don't
take this to mean OAT antifreezes, it simply means a good quality
conventional inorganic solution. As far as I know, Mazda do not
recommend using OAT inhibitors for use in the Bongo produced for
the home market. Before using "Extended life" OAT antifreeze, you
should read and understand the history of these products.

[eoptio]

Hi all

brief update: weather held ok for most of today so most of it done: flushed system, replaced radiator, thermostat and the 4 main cooling pipes. Then it started to rain so will be filling with coolant and bleed the system tomorrow, fingers crossed all works ok....

Quick question on the bleeding: I have the various instrutions as per fact sheet and last newsletter. Just wondered ref the bit on putting the plug back in the bleed pipe. As it is not possible to do this with the funnel in place, I wondered what the best way is to do this and not get air back in: just undo the funnel whilst there is still coolant in there and hold the pipe down so coolant keeps streaming out then put the plug in?

K

[missfixit70]

Just hold it at a level where it's just trickling out & bung it in, make sure you don't scald yourself if you're doing it hot, wear gloves, it is very hot, it hurts & takes a long time to heal

[mikeonb4c]

Just hold it at a level where it's just trickling out & bung it in, make sure you don't scald yourself if you're doing it hot, wear gloves, it is very hot, it hurts & takes a long time to heal

And be careful even with gloves. If near boiling temp coolant soaks the gloves, the result can be worse than none at all (I tried gloves but took them off as soon as this started to happen - I think a woollen glove, for insulation, under a Marigold washing up glove, for waterproofing, must be the sort of thing thats needed).

I've been wondering about radflushing with Hols or similar and thought I'd see if I could gather more views on it. I found this item, which echoes what concerned me about radflush products from days of yore:

It is likely when you flush the engine coolant system you will have some problem at a later time you don't need, The flush is suppose to wash out all the crud but it actually breaks up the crud and not all washes out and causes at a later time to clog something up. I would never recommend a flush on any car or truck. You are better off to change the oil and coolant at a regular time

I found one or two other postings on other sites that were similar to this. Overall I find myself thinking that changing coolant at recommended intervals, and using recommended (50/50 in our case) coolant mix, is what you should do. If you are happy to pay for deionised water then that maybe is best. I used tap water on mine, but water where we live does not produce scale so I've not bothered. Once cooling system problems that appear to be linked to inefficient operation start to appear, then I would treat myself to a thorough radflush regime to promote loosening and scouring of any coating in the engine block bores, using the assumption that the radiator would act as the sedimentation tank. I'd then throw the radiator away and fit a new one. Given that the problem might well have been caused by failure to change coolant regularly (and/or using recommended mix) I'd assume the water pump efficiency might be degraded by erosion, and it fit a new one of those. I'd also fit a new thermostat, and replace the most common problem causing hoses if they looked the least bit suspect.

Of course I'd have a low coolant alarm and a TM2 engine block temp alarm fitted before and after so I was in touch with what the engine was up to.

It's great to have a dream - maybe I'll do it one day

PS - good luck refilling the system and hope (expect it will) everything runs nice and cool after your work.

[missfixit70]

Just hold it at a level where it's just trickling out & bung it in, make sure you don't scald yourself if you're doing it hot, wear gloves, it is very hot, it hurts & takes a long time to heal

And be careful even with gloves. If near boiling temp coolant soaks the gloves, the result can be worse than none at all (I tried gloves but took them off as soon as this started to happen - I think a woollen glove, for insulation, under a Marigold washing up glove, for waterproofing, must be the sort of thing thats needed).

I've been wondering about radflushing with Hols or similar and thought I'd see if I could gather more views on it. I found this item, which echoes what concerned me about radflush products from days of yore:

It is likely when you flush the engine coolant system you will have some problem at a later time you don't need, The flush is suppose to wash out all the crud but it actually breaks up the crud and not all washes out and causes at a later time to clog something up. I would never recommend a flush on any car or truck. You are better off to change the oil and coolant at a regular time

I found one or two other postings on other sites that were similar to this. Overall I find myself thinking that changing coolant at recommended intervals, and using recommended (50/50 in our case) coolant mix, is what you should do. If you are happy to pay for deionised water then that maybe is best. I used tap water on mine, but water where we live does not produce scale so I've not bothered. Once cooling system problems that appear to be linked to inefficient operation start to appear, then I would treat myself to a thorough radflush regime to promote loosening and scouring of any coating in the engine block bores, using the assumption that the radiator would act as the sedimentation tank. I'd then throw the radiator away and fit a new one. Given that the problem might well have been caused by failure to change coolant regularly (and/or using recommended mix) I'd assume the water pump efficiency might be degraded by erosion, and it fit a new one of those. I'd also fit a new thermostat, and replace the most common problem causing hoses if they looked the least bit suspect.

Of course I'd have a low coolant alarm and a TM2 engine block temp alarm fitted before and after so I was in touch with what the engine was up to.

It's great to have a dream - maybe I'll do it one day

PS - good luck refilling the system and hope (expect it will) everything runs nice and cool after your work.

Do the job with the flush properly & thoroughly as per instructions & you shouldn't have any problems, if it's that crudded up inside on the bongo, it's probably already blown it's head anyway
I'm sure it's possible to find enough generalised quotes to justify doing or not doing any of the jobs on the bongo for one reason or another based on "someobody's" opinion or experience

[mikeonb4c]

if it's that crudded up inside on the bongo, it's probably already blown it's head anyway

Indeed it probably has. I've lost count of the number of times we've advised people (painful though it is on the wallet) that just fixing a blown head without fixing the coolant system is to invite another blown head.

I'm sure it's possible to find enough generalised quotes to justify doing or not doing any of the jobs on the bongo for one reason or another based on "someobody's" opinion or experience

You're right and I wrestle with that one when looking up stuff on t'internet (including on Bongo Fury). Everyone has a view, and there's more than one camp. But old memories, my own gut feeling (which has served me well on many occasions though I generally underplay it), and some reports obtained from googling, all make me think that whats been did can't be undid. So changing coolant regularly, and sticking to recommended 50/50 mix, are the key to longevity. Once that has been neglected, the remedy doctors roll into town........

Be careful about following instructions. It was following someones 'instructions' (way back in Jan. 2007) I think that caused me to try wearing the glove that nearly got me a scalded hand. Make sure the glove provides insulation AND is impervious to water

[missfixit70]

There's instructions & there's advice - 2 different things all to be used with a sensible head on of course