I don't think I'd have the patience to explain it like CFI did, I just use big letters instead.



Humidity will not increase your coolant temps. Air does not condense on the condensor. You guys won't find a book explaining this any faster than you'll find a book explaining that humidity has no effect on what's on TV tonight.



If anything, humidity will make the car run cooler by some tiny amount, since humid air has higher enthalpy, it won't heat up as quickly through the condenser and radiator as dry air, and thus you'll maintain a higher overall temperature difference, which gets you more heat transfer.

 

IF we are talking about a residential window unit. The condensation from the evap. splashes on the condenser coils and on a dry day this helps remove heat better vs a humid day due to evaperation.
However, on a car, the condenser is in front of the radiator, and the evap. is located about 4 ft from it. So there is no dripping or splashing of the evap. water on the condenser.
As already stated, dry air is only cooler then humid air when evaperation can take place, such as your body sweating. Again, the dry air has the ability to absorb more moisture and this process removes heat from your body. However, the radiator on a car does not sweat so no cooling takes place based on evaperation.
Just to add a little more from what I remember from school. Heat is energy. There are 2 types of heat. Latent, and sensible. Sensible heat is heat that can be measured with a thermonitor. It takes 1 BTU to raise 1 lb of water 1 degree. example. 1 lb 40 degree water to 1 lb 41 degree water.
Latent heat is the energy required to change water from a liquid state to a vapor with no increase in sensible heat. It takes 963 BTU's to change 1 lb of 212 degree water to 1 lb of 212 degree steam .
And please excuse my bad spelling.

Edit to add, there will be no condensation on the high pressure lines. Only the low pressure side.

 

ok - I stand corrected..

 

very true. and many people dont realize by just how much.

96 deg. air can hold 8 TIMES more water vapor than 42 deg. air can...
the Relative Humidity index takes this into account. it factors in the ammount of moisture the air is capable of holding at the given temperature, which means that 50% RH at each of the above mentioned temps is a very different ammount of actual moisture content for a given volume of air...

 

Yes, but spraying cool water from a hose on the condensor is an easy way to see whether or not you've got a blockage or pressure problem.

As to the a/c, the gas itself is never exposed to air (or if it is, you've created a problem), so temperature is all that matters when it comes to pressure. Humidity is a factor though with what's going on at the Evaporator and a few vent temp performance charts show those numbers. My earlier post was to point out that compressors wear and as they do, the can shed metal which lodges in the screened orifice. The tolerances are tight and it doesn't take much to create a restriction that raises pressure. When that happens, the high side creates more heat than it was designed to handle. When it reaches the blowup point, it shuts off (at least you hope it does) - but there's some space between ideal and catastrophic that creates problems. Gages - or a scan on everything built after '90 - will show you what the pressure is.

The other issue is overcharging - particularly if the car has been converted to R134. That molecule is smaller than R12 and the tendency is to cram too much into it. Fan control is also an issue with these cars because the R12 system turns the fans on a little later. Some too, add refrigerant without paying any attention to how much it needs and if it's losing gas, it's usually losing a little bit of oil and that creates additional wear which means more metal in the orifice.

More esoteric items would be shrouds that no longer fit right or are damaged or simply falling apart (not a bad idea to check the last thing you did since for me, that's often the reason the next thing is broken). Electric motors that no longer spin as fast because of high resistance in the wiring or weak alternator outputs.

 

My 95 had a similar problem, but went to about 230F. It was the wrong type of thermostat. You can't just use any 160F thermostat, it has to be one specially designed to work in the LT-1. The correct one has a very long spring body as compared to other units.

Just my 2 cents worth

 

radiators cool the trans temp better than air what is the trans oil temp?

 

Good info here. Thanks

My thermostat is the correct type. It's been in the car for several years. I thought about it being bad but the only time the temps rise is with the AC on. I'm still thinking it's an airflow issue. I havn't had it running in traffic lately to check the second fan.

My trans temp is always lower than my coolant temp. The highest I have seen it so far is in th 190's. That was at the track with about 11 back to back runs. It usualy ranges from 160's to 180's depending on the outside temps and driving conditions. It is much cooler with the external B&M.

 

I was able to get it up to 225 after some driving in traffic with the AC fully on. I got out to check the fans and only the drivers side was spinning. I don't remember the stock tune fan on temp. I'm going to check my PCMFORLESS tune now to see what it is set at. What should I check besides the connection on the second fan? Is there a fuse or relay somewhere?


Thanks

 

Heres everything I see relating to fans in the tune.

 

Rick, I think the AC overrides the fan settings and brings on both fans when the ac is on. On mine, (93) there is a fuse panel out under the hood, and I think it was near the battery. Anyways it has very large fuses in it and I had a blown one on mine. Replaced it and it blew again. Turned out my motor was shorted. If no one else post anything for you, I will check mine tomorrow and get back to you with exact locations. Good luck.

 

I think I know the fuse box you are refering to. It is right by the battery and has large fuses in it like you described. I'll check for a bad fuse tonight or in the morning.

Thanks

 

Looking at your Data - Main fan is commanded at 189 psi; secondary 225 psi. You can check the pressure signal when you scan it or with a manifold gage set. Unless I'm misunderstanding your tune, you mph off signals are well above cruise. Fans cranking much above 40 mph can impede air flow.

 

when your car was new, it cooled just fine. changing to electric water pumps, changing thermostat temps, fan blades, etc. does not fix the problem, it just makes a system compensate for the problem that has cropped up.
If another vette of the same year and options cools fine, you have to find out YOUR problem. Arguing about physics doesn't solve the underlying problem.
1. make sure the oil in your engine is of the proper mfg. required spec.
2. check to see there's enough oil in it.
3. if it cools when going fast, and doesn't cool when going slow, it's an airflow / water circulation problem.
4. what was the summer operating temp last year?
5. What prompted you to install a new radiator?
6. when was the last time you replaced the water pump?
7. when was the last time you inspected the belt tensioner?
8. are you sure the temp sensor is not out of calibration?
9. do you have too much coolant vs water in the engine?
10. are you sure your waterpump suction hose isn't collapsing? Some of the springs in the hoses coming from other countries aren't holding up and rust away, leaving hoses to collapse.
11. Mr. Mojo is right, a/c on fan programming is different than a/c off fan programming.
12. normal freeway speeds, (75 mph) should yield 180 to 192 degrees with a 180 thermostat when it's cool.
13. but in the summer, temperatures are elevated, and cool air is not available, so you have to cool your engine with warmer air. This means hotter temps in the summer.
14. my car runs 100 degrees over ambient in the summer in traffic. Stop and go traffic yields 205 to 214 with an ambient temp of 110 to 115 degrees. At 100 degrees, traffic driving (35-40 mph) yields 205 with 215 tops in miserable stop and go at every light with extended idling.
15. oh, by the way, my car is an 86. BEFORE they made all of the temperature cooling enhancements your car has. You need to spend some quality time evaluating the following areas:
A. airflow
B. water flow
C. fan operation
D. hood open vs hood closed operation
E. what mods were done, and are they hindering your cooling?
F. condition of existing cooling system components (all of them)
there are 3 ways to cool an engine....air, oil, water. Each of them play an equally important part. an inefficient one will affect the others
Just my 2c worth

 

I got my temp gauge working today, by switching in an autometer temp sender. So I have got a replacement from the auto store to try out now.

I ran the car and it went up into the 220s, then bobbled around in the 230s for a while and then worked on up to 240s and even hit 250 when I turned it off.

This was all sitting in my driveway. I have cleaned the debris from the area of the A/C condensor and radiator the best I could, new thermostat, the main fan runs whenever the key is "on" and I have not been able to check the aux fan yet.

This was with just water in the system because I was flushing things out and trying to just get the gauge working. I know that the water should heat up faster so I am curious how it will run with coolant back into the mix.

I bought the car with the previous owner telling me it overheated and a possible head gasket issue. I have also drained the oil and filter, and from what I saw there was not any sign of radiator fluid in the oil.

 

I took my autometer sender out and put it back with my gauge, and got a replacement sender from the auto store. Now the gauge once again does not read temps. Obviously something with the part the store is giving me. They have two options that show, with and w/o a warning light. I have yet to see a warning light come on in the car. I am going to return this unit again, and just return it this time but I would like to find one that works and get it put in.

 

After 45 minutes at the auto store it was finally decided the part I had been sold was wrong and I bought a new unit. This one works, so I can finally read my water temp gauge now!

Right now I am running just water through the system so I imagine its running hotter then it will once I put a 50/50 mix back in. I am considering doing the water pump while I have just water in the system to make it a less messy install.

 

I found the problem. The bottom relay on the side of the radiator cover was disconnected. It may have been like this since the Dewitt install in the winter. I have not realy used the AC until now. I plugged it in and the secondary fan started to spin. Thanks to everyone for the assistance.

 

Rick, glad to hear you found the problem. Mine was the motor died, but the effect was the same.