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md4406
New User
Aug 27, 2014, 6:02 AM
Post #1 of 4
(2450 views)
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1985 chevy el camino 305v8 50k original miles. Recently converted to r134a. low pressure 40 high pressure 220. no leaks. cools but not cold. I somewhat expected this. Mostly town driving but occasional freeway. Question is- will aux fan wired to come on when ac is on help ac cooling? No engine overheating is present. ac off or on. If aux fan will help how is the best way to wire it? Thanks.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Aug 27, 2014, 6:29 AM
Post #2 of 4
(2443 views)
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Anything the cool condenser better will help A/C performance. But wait a bit. This is a small cab so really shouldn't be hard to cool IMO even without wild antics converting it. Plain OE tube and fin condenser should work fine just whole set up slower to achieve it's best now and maxed out would lower A/C power or BTU ability about 20% which it should handle fine.
Before wiring up an aux fan try a stronger fan clutch. Actually they don't age well low miles or not they do lose it some over time as well. You want one that's thermostatically controlled should show an exposed spring looking thing towards front. Super cheap ones just set at one setting and make too much noise IMO.
More: Getting the refrigerant charge just right for the exact car is a game now. The standard use 80% of the listed OE charge may NOT be its best spot.
In fact starting at perhaps 65% working up an ounce at a time, taking it around the block and check everything again you can usually find the sweet spot. Most shops wouldn't take the time and it does.
For a test just spray condenser with water which is much more effective than air and that should show the best it can do with the conditions and charge its in at that time with a raised idle for actual pressures. Performance with fan on high, recirculate, windows open at center vent should easily be able to blow mid to high 40sF,
T
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md4406
New User
Aug 27, 2014, 6:49 AM
Post #3 of 4
(2438 views)
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Thanks. Obviously, fan clutch is original. I will check to see if it has the thermo spring. As I stated there are no other overheating problems. I don't really want to evacuate and start over with 65% and work my way up. Just thought aux fan would be the least expensive and simplest way. Don't know what air temp blows out of vent yet. Couldn't find thermometer. With mostly town driving I have to keep it on max[recir] and it is only cooler by the time I get where I'm going. Thanks again! More research and I will let forum know what my prognosis is. I don't want to start throwing parts at this for no reason.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Aug 27, 2014, 9:18 AM
Post #4 of 4
(2427 views)
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Fan clutches new in a box are NG at that age - no kidding and must be stored properly or leak out fluid. This one can't be much good and still not surprised it doesn't overheat.
Hey - the best ones for cooling engine and A/C performance roar too much for my own liking so I wait till they need it more or any sign of overheating which isn't good for anything ever. Low miles or not they shouldn't have much or any play either. Some will say a tiny amount is normal as measured push/pulling on fan blade and looking carefully that it's the clutch not the water pump - none allowed for those.
This is a helpful read on plain charging. It will still fall short as long as it is. Keep air OUT! Out of hoses, gauges always think of what is gas and what is exposed and what has the higher pressure which will by nature travel to any lower pressure. System in a perfect vacuum you lost it just hooking up to charge - it gets involved to be that precise.
Tweaking a vehicle to exact amounts (to an ounce for these) takes time as no two ever seemed to be identical and aren't for assorted reasons including how warm it is when doing it.
Have thermos everywhere. You really want to know the temp of air coming in thru the grille not the day's temp in a forecast as the surface you are on may make a wild difference and change all the pressures.
You observe everything getting it to it's best as there's no known exact charge weight I could give you for each converted car and most didn't care that much if off up or down some - much newer low capacity vehicles care a lot.
Write down for records how much of what you do for future use. Don't forget oil in system isn't moving till it can blow cool air so be fast and do it right from a vacuum if redoing it.
Ya - there are machines (huge bucks) you can go up and down measuring charge in and out wildly helpful but most wouldn't have access to nor a shop really want to spend too much time for this tweaking out a system.
Better than an electric fan but forget it was a flex fan not on a clutch. Dunno if even available and wouldn't unless you must max out all possible ways to make this cold, fast to do so and wild temps. IMO - not worth it as this car should be fine with no tricks.
Ask away if confused. Even this doing things wrong or mistakes can get nasty on you and make problems you don't seem to have now,
T
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