ac hoses

[1984red911]

So im about to start updating my ac as I live in miami and we don't have winter anymore, but have a quick question:
Is it necessary to drop motor to replace the hoses?
Any tips?
Tks

[88911coupe]

Lots of threads on this issue but quick answer is no, do not have to remove engine, however it is easier if it is already out for some other reason.

[beany]

I also live in Miami and a few years ago I replaced all the old hoses with the new barrier type hose. I had the car up on jack stands to give me more working room. One of the hardest parts was getting the new hoses hooked up to the a/c evaporator in the front of the car. If you take your time and limited your foul language so that no one else hears it, the job is very doable. Good luck. Beany

[wwest]

Originally Posted by 1984red911

So im about to start updating my ac as I live in miami and we don't have winter anymore, but have a quick question:
Is it necessary to drop motor to replace the hoses?
Any tips?
Tks

"any tips"

Yes, most certainly, just limit the refrigerant pressure below the design specifications of the factory hoses.

1.) RED DOT trinary refrigerant pressure sensor to control the compressor clutch cycling periods.

a.) sensor will protect the compressor by disabling the clutch circuit if the refrigerant level is to low.

b.) the factory thermostatic capillary switch clutch control system is highly prone to fail in a mode that results, might result, in refrigerant pressure well above the hose, compressor seals, etc, design specification. The trinary switch will prevent those types of failures.

c.) The third sensor element can be used to activate the cabin heater fan/blower in conditions wherein otherwise the refrigerant pressure might rise above the design specifications.


The cabin heat blower control module in the '83 through '88 series 911s has the ability to directly activate the cabin heater blower under conditions wherein the engine itself might be subject to overheating.

The cabin heater control module has two important signal inputs to support this function.

a.) speedometer input to monitor roadspeed.

b.) engine oil temperature thermostatic switch to detect rising engine oil temperature.

The cabin heater module will automatically activate the cabin heater blower should the engine oil temperature rise high enough that with continuing, consistent, low roadspeed operation the engine might well overheat.

The blower operation will help to cool the exhaust manifold thereby lowering the heat load to, on, the engine.

The third function of the trinary switch can be wired in parallel with the engine's oil temperature thermostatic switch, thereby providing additional cooling airflow through the rear lid mounted A/C condenser.

In my '88 Carrera activation of the cabin heater blower resulted in doubling the level of cooling air flowing through the rear lid condensor with the engine idling at ~800 RPM.

My '88 has an additional modification, a 15 minute TDR, time delay relay, connected such that power is provided to the cabin heater control module for 15 minutes post engine shutdown.

In HOT environments such as Olive Branch Ms in August, if you should happen to shut the engine down,HOT engine, in certain conditions(***) the rising convection engine/exhaust HEAT might well result in excessive refrigerant pressure.

*** Evaporator already at ~34F therefore TXV closed, an ounce or two of liquid refrigerant remaining in the dryer/filter, and compressor just having cycled off due to pressure sensor indicating that the maximum refrigerant pressure level has just be reached.

From the 964/993 series and throughout the water cooled 911 series, Porsche uses this same 15 minute TDR design technique to prevent engine/compartment heat rise post ignition shutdown.

Obviously I cannot say for sure that the above will prevent refrigerant leakage from the factory non-barrier hoses. On the other hand it will most certainly improve the effectiveness of the rear led refrigerant condenser during those times that efficiency improvement is most needed/desired.

However, there are several engineering white papers available on line that indicate R-134a leakage is NOT a problem when upgrading from an R-12 system. The explanation, apparently, results from the fact that the R-12 molecules have so permeated the non-barrier hose inner lining that they provide a barrier against R-134a leakage.

Since the Seattle climate is not exactly conducive to proving out the above design theory, my '88 is being shipped off to my nephew in Olive Branch MS for the summer.

I'll get back to you late September.....

[Barrpete]

No need to drop the engine to replace the hoses. The hardest part for me was snaking the new hoses back to the front condensor from the fenderwell. It's dark, dirty and you can't fit your arm in there very well to feel where the hose needs to go. I recommend tying a stout cord on the ends of the old hoses before you pull them out so you can use that to help guide the new ones back through. Also, if you're replacing with reduced diameter barrier hose the existing clamps will be too big so you might want to replace them some smaller loop straps.

[kuehl]

All the hoses can be replaced with the engine in the car. If you don't have a lift you can put the car on 4 jack stands, remove the LH Front tire and RH Rear tire.

Prior to jacking up the car drop the splash pan under the front cross member, do this while the car is on the ground (weight on suspension) so alignment of the straps relative to the the bolt holes in the tub is not lost; this is very easy to do by reaching under neath the car. 2 nuts on studs for the pan and 2 allen bolts for the sway bar straps. Re-install the 2 allen bolts & straps for sway bar and snug them up after you drop the splash pan. After you do this then you can jack up the car.

The evaporator outlet to compressor inlet hose in the engine compartment on the RH side is inserted into a slot up by the shock tower (near the RH heater box). Ditto on the deck lid condenser outlet hose to front condenser hose that is on the LH side. If you have difficulty pushing the new hose up into the slot into the engine compartment it is usually because it is getting hung up on the sound insulation mat.

For the 2 hose to the front condenser you do not have remove the water bottle, just duct tape the 2 new hoses together and slide them past the water bottle, wear a pair of safety glasses and from underneath the nose of the car just use a coat hanger to grab the set of hoses and pull them forward and down.

All Kuehl Barrier Hose Sets come with detailed instructions for the DIY to do the job right the first time.

[1984red911]

Thanks all for the great tips. Trying to remove water bottle, has been a challenge, still working on it.
on the rear have them loose and will try to remove right after I get the front ones out by pushing forwrd.
And yes, lots of damit, f&/^#, s//&/&^# being expressed, in this job.....

[1984red911]

Damned water bottle!!!!!!

[SilberUrS6]

Originally Posted by kuehl

All Kuehl Barrier Hose Sets come with detailed instructions for the DIY to do the job right the first time.

I was very impressed with the instructions. They are VERY detailed, and make the job much easier than if you had to do it via trial and error.

The longest part of the job, for me, was replacing the hoses. Everything else was easy.

[DRACO A5OG]

In a pinch you can re-use the fittings just have the hose company re=crimp them in the proper orientation. I did that and make sure you have the proper lengths.

While you are in there have a radiator shop test the evaporator and condensor checked for leaks. Hate for you to do all the work and find it leaking. Mine was leaking and had the shop fix it fr $20

[kuehl]

Car is on jack stands, properly supported, and the tires you took off the car are under the tub for the "just in case":

You do NOT have to remove the water bottle.

Simply use 2 wrenches on the hose fittings at the front condenser, one to hold the fitting nut on the condenser, and one to hold the fitting nut on the hose end.
Lefty loosey, righty tighty.

After the hoses are disconnected at the front condenser, and and at the drier inlet and the deck lid outlet, you can cut the 2 old hoses in the LH front fender area that connected to the front condenser.

Crawl under the front of the tub, with safety glasses, shine a light upward underneath the tub toward the side of the front condenser. Pull the cut hose ends downward.

Take the 2 barrier hoses that will connect to the front condenser, the one from the rear deck lid condenser outlet and the one to the drier inlet, have caps or tape sealing off the ends of the hose fittings so dirt does not get inside, wrap some duct tape around the ends, slide them along side of the top of the water bottle and push past it. Crawl under the front LH side of the car in front of the wheel well, with safety glasses on, light shining upward, look up and you can easily find the 2 hoses. Take a coat hanger, bend a hook on the end, carefully grab the hoses and carefully pull downward. Avoid tangling the hoses in the front marker or fog light wires. Remove the duct tape and caps and attach to the front condenser; does not matter which hose connects to which side of the front condenser. 2 wrenches to snug them up. Use new tie wraps to secure the hoses, gas expansion tank vacuum line, overflow tube, water bottle lines together, re-install the hose clamps (you will see the old 'witness lines' where the hoses were routed under the fender). Shop vac handy to vacuum up the dirt that falls out, yada yada

All Kuehl Barrier Hose Sets come with detailed instructions, cut to proper length, fittings properly orientated, ends capped off, each hose labeled so you know where they go : for the DIY to do the job right the first time (unless of course you enjoy reading these threads).

[1984red911]

I was able to get one out, the other was stubborn so took ur advice and cut it.

So up front I'm done. :-)

Now, to the back, I already removed compressor and condenser.

I'm having second thoughts on this job

[kuehl]

Do you have a new set of barrier hoses, orings and a drier?

[1984red911]

Draco, good tip about the test, will have that done on deck lid condenser, I think I had read one of your previous posts about the re-crimping and found a guy who does it so will be going that route.

Kuehl, sent u an email

[wwest]

Originally Posted by 1984red911

Thanks all for the great tips. Trying to remove water bottle, has been a challenge, still working on it.
on the rear have them loose and will try to remove right after I get the front ones out by pushing forwrd.
And yes, lots of damit, f&/^#, s//&/&^# being expressed, in this job.....

Back when an R-12 recharge was an expensive matter hose leakage was definitely worth addressing. But nowadays you can fully recharge your system each spring for less than $30.

My '88 seemed to have only lost about 1/4 of the charge come the next spring.

[wwest]

Originally Posted by 1984red911

I was able to get one out, the other was stubborn so took ur advice and cut it.

So up front I'm done. :-)

Now, to the back, I already removed compressor and condenser.

I'm having second thoughts on this job

Sorry, to late for second thoughts....unless those thoughts lead to hiring it done...

[Jesse16]

Did you already purchase your replacement hoses ? If not, I'll have a set of relatively new barrier hoses that I purchased from our host available in a week or so. I've got a griffith system coming that includes its own set. I had put on this set 3 years ago after I had an original hose blow out. If not, the system parts I don't need will all be on the for sale forum pretty quick. Evap, front condensor, compressor, and hose set.