I'm about to tackle the replacement of the evaporator, heater core and
receiver-drier on our '02 300M.
1. The service manual says to drain the cooling system, but could I get
away with simply clamping the heater hoses shut before I disconnect them
from the heater core?
2. Other than the 1oz. of oil in the receiver-drier and 2oz. that is (or
should be) still in the evaporator, do I need to replace any additional
oil that might have been lost when it went "Pffft!" and stopped cooling?
Is there any alternative to removing and draining the compressor, then
calculating the amount of new oil I need to add?
"Percival P. Cassidy" writes:
Probably not. You really want the coolant out of the heater core and
heater core lines before you take that apart, unless you really like the
idea of taking a bath in what spills while you're working on it -- and
when did you last change the coolant, in any case? Whenever I do a job
that calls for draining and refilling the coolant I figure it's a good
time to change it.
I've never seen a good way to estimate this....
I'm pretty sure I had the coolant changed when I had the timing belt,
idler pulley, tensioner and water pump replaces (approx. 100K miles, and
the car still has only 118K miles, so I don't think it's due for a
coolant change for a good while yet.
You mean that even the method described in the service manual isn't
reliable? I know it's not possible to have a dip stick in the
compressor, but wouldn't it have been possible to have a sight glass?
The table of component capacities in the service manual has an item
"Line Blown" with a capacity of 1.5oz.; is it safe to assume that that
1.5oz. is still there? Is simply adding 3oz. (1oz. for the
receiver-drier and 2oz. for the evaporator) as good a guess as any?
Did you ever download the sections of the factor service manual that I
posted links to back in April?
Could get messy. You can drain the system and save the coolant to pour
back in if it's not too old.
I've not had to deal with any of those issues with my '00 300m. AC
still works great - but I don't use it that much. Over the course of a
year, I probably use the defrost setting more often than the A/C (in the
summer I tend to like having the windows open, even if it's hot
outside. I do mostly short trips - not much long distance highway
driving where I would have the windows shut and the A/C on).
Are you the one with the 300m that has really low milage - or am I
thinking of someone else here?
Yes, I did, and I'm sorry I didn't thank you at the time. But the '02
manual I had already is, understandably, more in conformity with my car.
So far I am managing without AllData or Mitchell, but I did find one
point at which the official manual had one particular step in an
impossible place: to remove a screw that was not accessible until
several steps later.
I'm all set to remove the instrument panel next, but it's very hot, so I
came in to cool off.
Replaced about 20K miles ago.
I tolerate the heat much better than SWMBO does, but it was definitely a
nuisance not having demisting/defrosting in the winter.
Now at 118K miles. Not a huge mileage, but I've read that Chrysler
evaporators frequently develop leaks.
Original owner of a 2000 3ooM with 35,000 miles on the odometer.
Only problem I've had with mine is the foam surrounds detaching from the
baskets on the 6 1/2 inch front door speakers.
I have at last got everything apart and have almost all that I need to
restore it to normal operation,
Removing screws, nut, bolts and air-circulation pipes, and disconnecting
electrical connectors to remove the whole instrument panel/dashboard was
tedious but comparatively straightforward, except that not all the
connectors' "latches" worked the same way: some were press-to-release,
whereas others had to be pried outward to release the connector.
The real nightmare was disconnecting the heater hoses at the firewall:
the spring hose clamps were extremely difficult to release with the
tools I had and not easy to release even with the special tool I bought.
Even after moving the clamps out of the way, getting the hoses off was
not easy. I ended up slitting the heater-to-block hose and buying a new
one, but I persevered with the other one because of the difficulty of
getting at the other end to remove the clamp. The service manual said to
replace the clamps by new ones of the same kind, but nobody seems to
sell that size, and even the Chrysler dealer said they just discard them
and use regular screw hose clamps because the fancy spring clamps fail
too often; it's a good job I happened to have a stash of the right size
regular clamps, because they are very difficult to find just now as a
result of the lawn-sprinkler maintenance being performed during our
The heater core I had bought from Advance Auto Parts too long ago to
return fits but has a pathetically small surface area compared to the
original; maybe it would be fine in a climate where the winters are not
as severe. I now have from NAPA one that looks identical to the original.
The evaporator core I had bought from Advance too long ago to return
turned out to have a different style of connector from the original, and
at the NAPA Web site I discovered that there had been a change during
the model year and that I needed one that was specified for the '03 model.
I guess I can sell the other heater and evaporator cores on eBay.
The one thing I have not been able to buy is the Styrofoam insert that
goes under the evaporator. The original was in a real mess as a result
of the leaking PAG lubricant, and the only way to buy it was, the
Chrysler dealer told me, as part of an HVAC installation kit that had to
be ordered specially (US$103), but when it arrived it did not include
that item; it turned out that the parts guy did not know what Styrofoam
was and was thinking of the soft foam that is used in various places in
the HVAC system. They eventually found out that it comes with the
genuine Chrysler evaporator (US$416) and is not available otherwise, so
I'm going to make do with the original one, crappy though it may now be
-- perhaps with a layer of duct tape over it.
In addition, once I removed the air cleaner I could see that a clamp
holding the suction tube/hose in place was almost totally eaten away and
that there was white corrosion on the tube at that point; that most
likely explains the gradual deterioration of the cooling function before
it finally died with a hiss. I got a replacement from Advance, who
messed up the expedited shipping I requested but ended up by refunding
the whole of the shipping charge. NAPA and Autozone list only the
discharge hose, not the suction hose.
The receiver-drier I had bought from Advance appears to be fine.
Once you get it all back together and working you'll feel like you
just completed a moon landing. I always feared working on AC due to
some unpleasant experiences years ago but recently have finally gotten
the hang of it. And saving $1500 in the process is not a bad reward
Would a salvage yard have the styrofoam? I am able to find many parts at my
local "you pull it" salvage yard for very little. But then again, maybe they
would not have been in any better condition than the one you already have.
It turned out that the suction hose I had purchased from Advance Auto
Parts did not fit, thanks to the mid-year engineering change. I was able
to return it to one of the local stores, but the only '03-style suction
hose I could track down was a genuine Mopar one with a list price of
$122, but I discovered "We R" Mopar" (wermopar.com), which shares a
physical address with Taylor Chrysler Dodge Jeep in Bourbonnais, IL) and
sells the genuine article for only $80.03. I told the customer service
person the VIN of my vehicle and he was able to tell me the exact part
number I needed, although I still had to order it on their Web site.
I had thought originally that I would put everything together at least
to the point of being able to drive the car to an a/c specialist to
evacuate and recharge the system, but I realized that if a leak were
discovered at that point a great deal of disassembly might be necessary
to remedy it, so I got an el-cheapo vacuum pump and gauge set at Harbor
Fright (and was able to use some coupons as well, to lower the price
still further) and was able to do everything myself.