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From digest.v7.n198 Sat Aug 30 23:07:09 1997
From: "Chao, Harvey" <Chao#m#_Harvey_at_msgate.wdl.lmco.com>
Date: 30 Aug 1997 21:17:13 -0700
Subject: Lssns Lrnd, E28 hi Temps (Long)
This got pretty long, if E28 running too warm problems aren't your =
problem you may want to skip it.
Lessons learned regarding an '86 E28 eta running warm.
Compared to the earlier ('83) E28 I had, this one always seemed to run =
warmer, and in particular on warm days when traffic bogged down or came =
to long red lights and stop 'n go with the a/c running,-- it would heat =
up to about the 2 o'clock position on the temperature gauge - and I was =
nervous it might skyrocket on me. When traffic would finally start =
moving, it would take several miles and or a very long time (compared to =
the '83) to eventually cool down back to the 12 o'clock position.
Tried the cheap'n easy things first, made sure fan clutch was good, =
flushed cooling system (stuff came out essentially clear), new =
thermostat, and made sure belts were not slipping, added water wetter to =
the new coolant. [Side note - I added water wetter to the car when I got =
it and it helped the temperature some, and after the cooling system =
flush, without water wetter it seemed to run warmer than with it before =
the flush, so added it to the new coolant.] Still no help. I knew when =
I bought the car that this was going to be an issue, because it ran warm =
then, and there was a good film of brown "mung" inside the plastic =
coolant bottle. I cleaned that out, and when no film came back to =
replace it, I was hopeful that with fresh antifreeze in the system, =
perhaps the problem had gone away (fool that I was).
Well the problem persisted and so this morning, having exhausted the =
cheap and easy solutions, I replaced the radiator with another factory =
oem Behr unit. Driving conditions and weather will tell in the coming =
days if this fixes it.
By the way I priced radiators at 4 local sources in the SF Bay area and =
got prices ranging from $272 =3D> $309 plus tax, with BMWCCA discount. I =
also contacted two list mail order places. Although they both had the =
same price (no tax, but add shipping), one was not an OEM Behr unit, and =
although the other was, as I thought about shipping a large flat box =
cross country, all I could think of was that "Murphy" is alive and well =
and could almost count on getting the box with a "through hole" right in =
the center of the radiator (so I'm paranoid- doesn't mean that "they" =
aren't out to get me anyway! :-) ). Decided that rather than risking =
the hassle of shipping damage and the attendant delays, although I really =
would have liked to order from the East Coast OEM supplier that I =
respect, I didn't want to risk the hassle and delay of possible shipping =
damage (OK - call me "chicken"). Perhaps, I have reflected, that mail =
order is best for things less fragile or vulnerable to damage. By the =
way, the place that I did buy from invoiced the list price of the =
radiator as $357.73 vs. the BMWCCA discounted price of $272 plus tax.
Being a masochist at heart, I was curious to see the state of the old =
radiator. Having been told from multiple places, (radiator shops, =
dealer, independents) that these aluminum radiators with crimped on =
plastic tanks are "throw-away" and cannot be disassembled, rodded and =
then re-assembled, and having already bought the new radiator, what have =
I got to loose, and what can I learn if I try anyway? Well, using a =
medium blade (1/4") screwdriver, I placed the blade between the plastic =
tank and the "dimple" at each point along the sides, top and bottom of =
the tank, twisted the blade at each dimple and simply bent the =
surprisingly soft ductile aluminum metal (some aluminum alloys are very =
hard and brittle) until the "dimple" cleared the edge of the tank - =
basically this bent the crimped band of metal out and "down" from the =
edge of the plastic tank. Although I have not bothered to try to =
re-assemble it, I think that for any of you who are "financially =
challenged enough, you may try this, it is a possible "can do" if you use =
some kind of gasket "goo" between the old gasket and plastic tank flange, =
and then use a large pair of arc joint or water pump pliers to bend the =
crimps back in place, perhaps finishing up by tapping the original crimps =
back with light taps from a hammer on a screwdriver handle with the blade =
placed on the crimps (indentations). Let the goo set up overnight and =
then pressure test. If it doesn't work, the worst is that you wasted =
some time and still have to buy a new radiator.
When I took the tank off (The output side) the end of the radiator and =
the inside of the now exposed end of the tank were well coated (about =
1/16" deep) with the brown "mung" that probably is a mixture of rust and =
scum, particularly on the ends of the exposed tubes that run from the =
input to output tanks across the width of the radiator. This was in =
spite of recently thoroughly flushing the system with a chemical flush =
and then rinsing both the system and the radiator together and separately,=
in the normal circulatory direction and in reverse. While moist, this =
stuff rinsed off very readily with the pressure of a stream of water from =
a garden hose nozzle. But, when I used the hose to flush water through =
the radiator from the remaining tank to the exposed end of the radiator, =
although the water flowed freely enough to not generate any appreciable =
back pressure at the hose, I was able to look at the flow through the =
tubes of the radiator core and see that about 1/3 of them had no flow at =
all! Most of these were along the front row of tubes, and were mostly in =
the center of the radiator and towards the top (i.e. the bottom radiator =
tubes were in fine condition). I tried to force water through the =
individual clogged tubes using a regular garden nozzle and then a with a =
high pressure "sweeper" nozzle - no dice. I then used a piece of piano =
wire to try and "rod" the clogged tubes. With significant difficulty, I =
was able to clear a few of the tubes that I tried. It was clear that =
these tubes were seriously clogged - it took perhaps 5 minutes of up and =
down with the wire held with pliers to eventually work it the length of =
the tube, using a flow of water to flush the "mung" out as I worked.
My best conclusion is that one of (or both) of the two previous owners of =
this car got careless and let the antifreeze deteriorate to the point =
where rust started to occur and allowed it to clog the radiator (makes me =
wonder about the state of the heater core now!). I think that next time =
I flush the cooling system, I will probably go with the stronger flush =
(the kind that requires a post flush neutralizer step) and see if I can't =
work at cleaning the cooling system and heater core out more thoroughly.
Hope that some of you may benefit from this and that it wasn't a total =
WOB!
Harvey
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