Automotive Air Conditioning Information Forum (Archives)

pippo on Fri July 23, 2010 3:42 PM

Have an Alfa Romeo spider, 1987. There is a rad temp sensor mounted on the inside of the rad fan shroud. Its a "button" type, kinda thick for a button. 2 wires attach to it, and Im sure you pros know more than me, it tells the computer to kick on the condenser fan when the temp of the rad gets higher than normal, right?

Well, one of the leads keps falling off. tried silver soldering it 2 X, but man, thats a sensitive solder job. Anyway, Im driving it now for weeks with no rad overheating problem. Should I worry then about this sensor? It seems like some of these sensors were overkill, I dunno, since the alfa's fan runs constantly, as it is mounted directly on the belt-to-pulley system....

Thanks!

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beware of the arrival

NickD on Fri July 23, 2010 7:05 PM

A rad is a unit of energy absorbed from ionizing radiation, equal to 100 ergs per gram of irradiated material, but don't feel you are referring to that.

But I lack familiarity with an 87 Alfa Romero but not with a radiator temperature sensor. A far more intelligent means to kick on the radiator fan than using the engine coolant temperature sensor as the typical value they kick on at is 160*F to maintain a constant engine temperature. Whereas the ECT sensor doesn't kick on until the engine reaches around 220*F where its about to over boil. Plus particularly in city traffic, causes extra engine wearing thermal cycling between 195 and 235* F that really stresses the head gasket.


Weren't these leads just lead/tin soldered on? Silver solder requires a lot of extra heat that may have ruined your sensor.

ice-n-tropics on Fri July 23, 2010 10:14 PM

I don't think Alfa Italy or Alfa USA had a approved Spider A/C before about 1979.
Some 1970s and 1980s A/C for various applications used a KLIXON bi-metal temp sensing switch firmly clipped to the condenser tube to activate a cooling fan or was used to shut off the compressor at high discharge gas temperature. It was constructed with a female channel which contacted the tubing for a portion of the tube circumference. Sounds like you have a switch similar to the Klixon and the old timers may have a replacement. Klixon was also used on commercial hermetic units.
My Spider A/C units up through 1986 MY did not need a auxiliary electric rad/cond fan. In the beginning (79-82), I used a Sanden comp mounted on urethane bushings (due to the high vib engine) located high on the left.
I even tested my Spider A/C Spider in Palm Springs and ran over to Vegas where the air 6" above the asphalt was 160 +F. Sure pity any poor soul who lives there!
Later I went to Alfa design center and worked on a very low Sanden compressor mount with a special oil pan with cast aluminum bosses for the comp mtg. bkt. Unfortunate Alfa Spider drivers would park by the Braille method by using the oil pan to feel the curb. Oil pans cost $475!
The 1987+ factory A/C had an improved below the dash evaporator which put more cold air to the driver's left side and total air flow increased from 200 CFM to 230 CFM. The Spider could use better body insulation, but convertables are hard to cool.
The Spider body would sure twist when driven at a angle across RR tracks.
hotrodac


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Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy.
AMAZON.com: How To Air Condition Your Hot Rod

Edited: Sat July 24, 2010 at 5:56 AM by ice-n-tropics

bohica2xo on Sat July 24, 2010 10:24 AM

Tex, I am just amazed you kept an Alfa running long enough to drive it from Palm Springs to here. Was there a truck & trailer full of spares and an Italian mechanic following you?

The heat's not so bad. When we want to warm up we drive to Death Valley - it was 127f there last week. Probably closer to 180f above the pavement... At least we don't have Chiggers, Ticks & Mosquitoes...

B.

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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

ice-n-tropics on Sat July 24, 2010 2:51 PM

Pal2xo
My better half gripes about the ticks and chiggers but I sulfur down.
Yea, I've called a wrecker with a Alfa Spider broke down in the boon docks.

Drove my personal 1/2 price Alfa GTV (V6) down from the port in NJ. It was wrecked driving off the ship and all damage replaced with new parts. Alfa service manager Roberto Franconi usually smashed the wrecks but offered me this GTV and said I would like the price. I had to work in Paramus nearby (Too many Sodomites in Paramus/ like Houston). Went to see Roberto to get the car he fixed for me and asked "By the way, How much do I owe? He said would 1/2 price be fair? Said OK, signed damage release and drove to TX. Never had a problem with the GTV except all the recalls, head gaskets and etc. Put a good A/C in it because Italian condenser and evap air flow was NG. Roberto recalled GTVs and installed my type condenser. Think they sold about 1800 GTVs at a loss that year.

Baker Grade leaving Death Valley is the radiator cooling boggey for all OEMs. I successfully drove it in a Mazda with Sanden comp.
Dodge RAM Van TR105 cycled like a Banchee on the TPS, discharge gas thermal protection switch, all the climb Not enough cond heat rejection
hotrodac

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Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy.
AMAZON.com: How To Air Condition Your Hot Rod

Edited: Sat July 24, 2010 at 2:56 PM by ice-n-tropics

bohica2xo on Sun July 25, 2010 6:04 PM

Wait - I thought we were talking about Italian cars? I think the Sodomite was a brit car...

My dealing with the Alfa were mostly the Marelli junk, and the DellOrto's - most of the Weber guys I knew would not touch that carb. I got them by default.

When they ran, they were fun cars. So was my Europa, on the days it would actually start...

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

NickD on Sun July 25, 2010 8:27 PM

Not sure why I didn't use a Klixon thermal switch when converting an aluminum head cast iron block engine to radiator sensing, would have been far simpler than using a thermistor feeding an comparator with a buffer to pull in the fan relay. Must have been in an overly complicated mood that day. Used thousands of these in the past for thermal protection and were dirt cheap when purchased in quantity, yet very reliable.



Considered that on my 92 DeVille in diagnostic mode can watch the engine temperature vary all over the place. But it has dual fans, each two speeds with four combinations to work out. Plus it has a cast iron head and block, and mostly drive it on the highway where the temperature is stable.

For a little four banger, the Cavalier has a huge radiator, so the condenser fan rarely if ever comes on, always read a constant 195 on the gauge, so that wasn't worth fooling with either. But does switch on with the AC.

Shouldn't have to buy something and have to modify it so it last a couple of weeks beyond the warranty period. But if it does last, you won't be in the market to buy another before the first one is paid off.

pippo on Wed July 28, 2010 3:45 PM

Quote
Originally posted by: NickD
Not sure why I didn't use a Klixon thermal switch when converting an aluminum head cast iron block engine to radiator sensing, would have been far simpler than using a thermistor feeding an comparator with a buffer to pull in the fan relay. Must have been in an overly complicated mood that day. Used thousands of these in the past for thermal protection and were dirt cheap when purchased in quantity, yet very reliable.







Considered that on my 92 DeVille in diagnostic mode can watch the engine temperature vary all over the place. But it has dual fans, each two speeds with four combinations to work out. Plus it has a cast iron head and block, and mostly drive it on the highway where the temperature is stable.



For a little four banger, the Cavalier has a huge radiator, so the condenser fan rarely if ever comes on, always read a constant 195 on the gauge, so that wasn't worth fooling with either. But does switch on with the AC.



Shouldn't have to buy something and have to modify it so it last a couple of weeks beyond the warranty period. But if it does last, you won't be in the market to buy another before the first one is paid off.

Sorry for delay, guys....was out of town. But, wow, Nick, that photo is helpful.....of the 6 , the one in the lower left would be the best match (mine is kinda simpler design, not sure why). On the lead/tin vs silver solder, you might be right with that. I just assumes silver cuz I understood thats what one SHOULD use for electrical, eh?

Now, back to basic question: My car does Not heat up. Currently, like I explained, that sensor is inactive, of course, since one lead has fallen off. So, arent these maybe kinda useless on these Alfas which have a radiator fan constantly running (theyre mounted directly to crank)?

Thanks again!!!



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beware of the arrival

pippo on Wed July 28, 2010 3:47 PM

Oh, I should say, that sensor mounts on the inside of the fan shroud(or maybe I said it already(?)). One hole of the mounting flange has a tiny screw that goes onto the blk plastic , top of the shroud.........just for the record.

Hey, kijnda side note: there seems to be no way to edit one's message once posted. Why?

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beware of the arrival

pippo on Fri July 30, 2010 9:02 PM

Quote
Originally posted by: pippo
Quote
Originally posted by: NickD
Not sure why I didn't use a Klixon thermal switch when converting an aluminum head cast iron block engine to radiator sensing, would have been far simpler than using a thermistor feeding an comparator with a buffer to pull in the fan relay. Must have been in an overly complicated mood that day. Used thousands of these in the past for thermal protection and were dirt cheap when purchased in quantity, yet very reliable.















Considered that on my 92 DeVille in diagnostic mode can watch the engine temperature vary all over the place. But it has dual fans, each two speeds with four combinations to work out. Plus it has a cast iron head and block, and mostly drive it on the highway where the temperature is stable.







For a little four banger, the Cavalier has a huge radiator, so the condenser fan rarely if ever comes on, always read a constant 195 on the gauge, so that wasn't worth fooling with either. But does switch on with the AC.







Shouldn't have to buy something and have to modify it so it last a couple of weeks beyond the warranty period. But if it does last, you won't be in the market to buy another before the first one is paid off.



Sorry for delay, guys....was out of town. But, wow, Nick, that photo is helpful.....of the 6 , the one in the lower left would be the best match (mine is kinda simpler design, not sure why). On the lead/tin vs silver solder, you might be right with that. I just assumes silver cuz I understood thats what one SHOULD use for electrical, eh?



Now, back to basic question: My car does Not heat up. Currently, like I explained, that sensor is inactive, of course, since one lead has fallen off. So, arent these maybe kinda useless on these Alfas which have a radiator fan constantly running (theyre mounted directly to crank)?



Thanks again!!!

Any knowledge on this from anyone here on the usefulness of this possibly useless sensor? Thats all Id like to learn about...

Thanks again, people.



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beware of the arrival