Partial antifreeze changes, pros & cons + can`t do the math :(

Any one in the USA done this? interested in a US perspective.
(hello from the UK)

Coolant system holds 6 litres. Header tank holds one and a half
Litres..(ethelene glycol at 50% as per manufactures spec)
I can suck out the header tank in seconds with a vaccuum fluid remover
and replace with fresh.
The engine bay is a nightmare for access, none from above to coolant
hoses (no drain plugs)
Even from underneath on ramps, lying on my back removing bottom hose
from rad , arm reaching up at full stretch into the engine bay, results
in an antifreeze shower down the arm, and only removes two and a half
litres.
To get more out from the block and heater hoses is even worse.
I wondered if anyone else just sucked out the header tank every 3
months or so instead?
Never had the pleasure to see under the hood of an American vehicle,
but hope you have more room in there , in general for access.
I was hopeless since shool in even simple math.... Ok.. even
arithmatic
But if I sucked out the header tank 3 times a year, can anyone tell me
how much percentage of old coolant I would be running with in the
system.
Any thoughts on this?
I`m just retired and trying to save on servicing (labour)costs, but
mainly trying to avoid a half day crawling under the car, soaking in
coolant.

How about removing the thermostat, removing the hose from the upper rad
tank, the lower rad tank and using a water hose flushing thru the upper hose
till the it runs clean, after draining as much coolant out of the block and
rad as possible.
"Mikail" > wrote in message
oups.com...
> Any one in the USA done this? interested in a US perspective.
> (hello from the UK)
>
> Coolant system holds 6 litres. Header tank holds one and a half
> Litres..(ethelene glycol at 50% as per manufactures spec)
> I can suck out the header tank in seconds with a vaccuum fluid remover
> and replace with fresh.
> The engine bay is a nightmare for access, none from above to coolant
> hoses (no drain plugs)
> Even from underneath on ramps, lying on my back removing bottom hose
> from rad , arm reaching up at full stretch into the engine bay, results
> in an antifreeze shower down the arm, and only removes two and a half
> litres.
> To get more out from the block and heater hoses is even worse.
> I wondered if anyone else just sucked out the header tank every 3
> months or so instead?
> Never had the pleasure to see under the hood of an American vehicle,
> but hope you have more room in there , in general for access.
> I was hopeless since shool in even simple math.... Ok.. even
> arithmatic
> But if I sucked out the header tank 3 times a year, can anyone tell me
> how much percentage of old coolant I would be running with in the
> system.
> Any thoughts on this?
> I`m just retired and trying to save on servicing (labour)costs, but
> mainly trying to avoid a half day crawling under the car, soaking in
> coolant.
>
>



----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

I agree Shep, Thats the logical way to do it.
The thermostat housing though has very poor access and several pipes
and sensors coming out of the housing itself, and just below. You can`t
even see the bottom housing bolt that fastens it to the block and it
looks as though all those pipes on the housing would have to come off
to be able to pull the housing away sufficiently to get the thermostat
out. Needless to say, those pipes are held on by hose clips that have
to be destroyed to get them off. I also have a certain reluctance to
deal with the bolts on the thermostat housing that go into the alloy
head. If one had a damaged thread it would be an engine out job to get
a thread insert fitted...
Overcautious perhaps... But I have had 2 experiences over the years
where bolts into alloy have been been cross threaded at the factory
and power tooled in...
Your suggestion is similar to good advice I received on UK forums, and
I have just done the job, taking the best part of a day on two cars.
Now its fresh antifreeze though. I was wondering whether anyone on the
US forums did partial, regular changes, with ethylene glycol (the easy
wayand if so what the results are.
Thanks anyway for the response.

I like your thinking here as a labor saving idea. Remember, if you
continue this program you will always have at least a tiny bit of the
original fluid in there. I don't consider that critical though.
Assuming the 1.5 liter tank is included in the 6 liter capacity then
you are draining 25% and keeping 75%.
First change = 75% left of original.
Second change = .75X.75 or 56.25% of original.
Third change = .75X .5625 or 42.19% of original.
So at the end of the year you have less than half the original fluid
left.
In the case you describe I think it makes sense. Eventually you have
almost none of the original.

And then to make sure it has the correct mix, you can just buy one of
those $5.00 antifreeze testers. They suck up some and give you it's
strength with a float reading.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Al Bundy wrote:
>
> I like your thinking here as a labor saving idea. Remember, if you
> continue this program you will always have at least a tiny bit of the
> original fluid in there. I don't consider that critical though.
> Assuming the 1.5 liter tank is included in the 6 liter capacity then
> you are draining 25% and keeping 75%.
> First change = 75% left of original.
> Second change = .75X.75 or 56.25% of original.
> Third change = .75X .5625 or 42.19% of original.
> So at the end of the year you have less than half the original fluid
> left.
> In the case you describe I think it makes sense. Eventually you have
> almost none of the original.

Al Bundy wrote:
> I like your thinking here as a labor saving idea. Remember, if you
> continue this program you will always have at least a tiny bit of the
> original fluid in there. I don't consider that critical though.
> Assuming the 1.5 liter tank is included in the 6 liter capacity then
> you are draining 25% and keeping 75%.
> First change = 75% left of original.
> Second change = .75X.75 or 56.25% of original.
> Third change = .75X .5625 or 42.19% of original.
> So at the end of the year you have less than half the original fluid
> left.
> In the case you describe I think it makes sense. Eventually you have
> almost none of the original.

True, but when would one consider the fluid that was added in the first
and second change "old"?

Hi Larry, When its been in 2 years. Thats as good a definition as any,
when it gets to the normal time for changing.
I am assuming the rad would more or less stabilize at some point?

I won't go into the simple math behind the next statement. However, you
could easily compute the "average age" of your fluid at any time while
using the process that you intend. Since you only have 42% of the
original after the first year you are doing better than the average
change interval that most people use of say three years.( I drain mine
every year.)

My only reservation about it is that when draining you are more apt to
get some of the migrating grit that is in the system. I think that's
minimal though. When I strain my drained fluid the only grit I see is
what dropped from the frame and such as I was doing the work.

Thanks Al, I just can`t do the maths even though you say its simple
Seeing as you have this ability and obvious mechanical knowledge can I
ask your opinion on the following?
I chose 3 times a year as a "reasonable" number of times, but I could
just as easily make it 4 times. Or even do 4 or 5 "suckouts" of the
header tank once a year, say spread over a weekend.
Its the optimal figure i`m looking for , given that diminishing returns
applies.
I`m not bothered about the cost of the antifreeze, more trying to avoid
the very considerable struggle of doing a conventional change on these
difficult access vehicles.
Its a Fiat 1.9 JTD direct injection diesel in a Doblo, in case you were
curious.
Thanks again for the advice.
http://www.honestjohn.co.uk/road_tests/?id=159

"Mikail" <do
> Any one in the USA done this? interested in a US perspective.
> (hello from the UK)
>
> Coolant system holds 6 litres. Header tank holds one and a half
> Litres..(ethelene glycol at 50% as per manufactures spec)
> I can suck out the header tank in seconds with a vaccuum fluid remover
> and replace with fresh.
> The engine bay is a nightmare for access, none from above to coolant
> hoses (no drain plugs)

can't you get the vacuum tube to go into the radiator (remove cap)
you should be able to remove 75% of the fluid that way..