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Topic: 88 T/C Overheating only with A/C (Read 5786 times) previous topic - next topic

88 T/C Overheating only with A/C

Reply #15 –
I agree Foe, shouldn't need the fans on above 35 mph or so. Never considered that leaving them on could block air flow. I was looking at some photos of the contour fans,  it looks like the shroud may cover the entire radiator, maybe at highway speeds the shroud is limiting the air flow also.

88 T/C Overheating only with A/C

Reply #16 –
double post

88 T/C Overheating only with A/C

Reply #17 –
Anyone in the know knows that a constantly running fan is NG and actually can reduce the engines HP. BUT i have been known to run some dual fan setups on low speed. That would be ONE fan on low speed and never both of them.
I spend money I don't have, To build  cars I don't need, To impress people I don't know

HAVE YOU DRIVEN A FORD LATELY!!

88 T/C Overheating only with A/C

Reply #18 –
all valid points and theories  but the fact of the mater is at hwy speeds without the a/c on and the fans shut off the temp starts to increase once you turn them back on it starts to drop so they are actually doing something. im sure the

88 T/C Overheating only with A/C

Reply #19 –
condenser is a bit of a restriction.

88 T/C Overheating only with A/C

Reply #20 –
Quote from: 5lturbocoupe;415893
all valid points and theories  but the fact of the mater is at hwy speeds without the a/c on and the fans shut off the temp starts to increase once you turn them back on it starts to drop so they are actually doing something. im sure the

Then either the radiator is to small over cooling or the air over the core is not there!!!
I spend money I don't have, To build  cars I don't need, To impress people I don't know

HAVE YOU DRIVEN A FORD LATELY!!

88 T/C Overheating only with A/C

Reply #21 –
If you've got to have the fans running at highway speed, I'd take a serious look at how much air is getting up into the cooling equipment.  TC guys have problems without a proper air dam, but from the pics, yours looks adequate.  Possibly it's not directing air up from under the bumper properly.
 

88 T/C Overheating only with A/C

Reply #22 –
with the car at idle and the fans on i took a 4x4 piece of newspaper and placed it under bumper holes and it sucked it right up lots of draw. on a 60-70 deg with cool air and sunny out at highway spd 70mph rev 2k fans  & a/c off temp went from 172 to 180 and stayed. in 4th at 2200 rpm 50mph no fans temp goes up from 172-190 turn fans on cools to 172, turn the fans back off do the same speed as before but in 5th less rpm and temp barely climbs mind you outside temp is about 55-60 deg. will do some more testing when the weather gets warmer. thank for your imput

88 T/C Overheating only with A/C

Reply #23 –
OK so when the RPM slows down the TEMP goes down..

With that does the water pump slow down as well ?????

Over cooling crossed you mind. Just a thought!!

Does the TEMP drop if you run the heater full blast on the highway ??? Does that make the temp come down ???
I spend money I don't have, To build  cars I don't need, To impress people I don't know

HAVE YOU DRIVEN A FORD LATELY!!

88 T/C Overheating only with A/C

Reply #24 –
I did think about over cooling and i did try a regular 180 t stat last year no difference , i have not tried the heater core fan to cool the engine what are your thoughts there? There is a interesting read on cooling systems @ http://www.flowkoolerwaterpumps.com/cooling_faq.html in the cooling facts section. yes i do have one of their water pumps installed this season and no difference, so i'm leaning towards rad a buddy lent me his 3 core copper rad which has the exact same fans as mine to try but not before i take it to a local rad shop they said they could have a look to see if i have enough fan,i went to ask on how much to make me a copper rad like my friends and he cant believe that the aluminum rad i have wont cool my car so he told me to bring it by.

88 T/C Overheating only with A/C

Reply #25 –
Well copper cools much better than ALUMINUM!!! I am not buying the guys theory on over cooling. No stat or a stat that is to low causes cavitation in some instinces. Just a thought. Running the heater at full speed will tell you your radiator is to small if the temps come down. heater core is basically an AUX radiator and cools the engine as well as the main cooling system. Good luck!!!
I spend money I don't have, To build  cars I don't need, To impress people I don't know

HAVE YOU DRIVEN A FORD LATELY!!

88 T/C Overheating only with A/C

Reply #26 –
quick update had the a/c pressure checked on 80-90 deg day hi side was at 325 psi we dropped to 230psi did a 10 mile run or so on hi-way and it didn't go past 190 ill have to test it on a longer run to make sure its all good.

88 T/C Overheating only with A/C

Reply #27 –
230 is not excessive, but I feel like it could be lower if your condenser was being cooled better.  I say that because high side pressure is directly affected by the temperature of your condenser.  If you want to see this relationship, monitor the high side pressure while spraying water on the condenser.  There is some contention as to the suitablility of the original R-12 style condenser in R-134a retrofitted systems, some say they work just fine (mine works well enough for me, but my cooling system thermal load is lower than yours), others will say you should have an updated Serpentine or Parallel flow style condenser as they disperse system heat more efficiently.  I suppose a worthwhile question to ask, since your condenser is new, is what style did you install?

88 T/C Overheating only with A/C

Reply #28 –
Well at 325 that is app 165* not to hot. But high for a car AC system. You fail to say at what RPM which is important. What was the RPM??? And you decreased the pressure by 100 PSIG. This tells me the system was overcharged. People not trained in ac always over charge systems. They think adding more freon makes the system COLDER. NOT TRUE. Whenever converting tou must use less R134 as it is more efficient than R12 and that is a fact. Also installing a more efficient Condenser is fine but it still has to dissipate heat. And that heat is right in front of your radiator. Once again either you radiator is to small or the air passing over it is not enough. Good Luck!!!
I spend money I don't have, To build  cars I don't need, To impress people I don't know

HAVE YOU DRIVEN A FORD LATELY!!

88 T/C Overheating only with A/C

Reply #29 –
By the sound of it, hi side got to 325 before the cooling equipment caught up and settled to 230 with airflow.  You see that when the fans don't kick right away or the car has a belt driven clutch fan.  I'm more concerned about the stable pressure of 230 with airflow.  It's not outside the temp/press chart, but I would like to see it lower.  As for charge level, Mine works best with 40oz or refrigerant, about 9% below spec.  At spec (2lb 12oz), I can't get discharge below 50f.  As per usual, your results may vary.