Overheating With Ac On

bmo37

Founding Member
Jun 27, 2001
2,368
2
46
New Jersey
I've batlled my fair share of overheating issues but this summer I've ran into an overheating issue that has me pretty much stumped. The car at this point has a new high flow water pump, new alumnin 3 core radiator, dual ford contour electric fans, new thermostat and cap, new hoses, system has been pressure and block tested. I also changed the the headgaskets anyway as a precaution. The car drives and idles @ 200 all day without the ac on. As soon as I turn it on she climbs and doesn't look like its going to stop (i usually turn it off once it gets to the R in NORMAL). The only thing I can think is happening is the condensor is dumping all the heat to the front of the radiator making it harder for fans to cool it. The ac blows cold (I actually re-did the ac with freeze 12 about 6 months ago with new dryer and o-rings on the system). Any ideas would be appreciated, I feel the issue is realted to the ac in someway as I pretty much changed everything cooling related prior.
 
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I would put a manual gauge in the car for the temp so you get an accurate reading.... my old hatch did the same thing turn the ac on and the temp would sit on the on the line right before 250* ...... put in a gauge it never actually got past 200.
 
I know this is off topic but... how is the tweecer? im havin probs getting my maf to read .6 at idle and car smells rich but reads lean.... was gonna take it down to have it tuned but the price for a tweecer is comparable... is it difficult to use/ worth the money.??
 
Its accurate I log tems on my tweecer when i tune.

That doesn't indicate that the sending unit isn't bad. The sending unit that's feeding your gauge is the same one feeding the TeEECer.

This is what it sounds like to me so far:

Your cooling system is probably overkill.
Just as soon as your T-stat creaks open, that's pretty much where the cooling system normalizes.
Now that it's warmer, you're seeing the temp gauge go higher than you're used to seeing, particularly with the A/C on.

The potential exists, that your cooling system is not running as hot as you think it might be. What T-stat do you have in?
I would get a MANUAL reading like suggested above before spending a lot of time and money trying to fix a problem that doesn't exist.

If the manual reading IS correct, then we'll dig deeper and find something else.

I'm sticking with this theory until disproved because I was once in this same boat. Fixed by problem by swapping out to higher temp t-stat that forced to cooling system to heat to the REAL 180* that I thought it had been all along.
 
I know this is off topic but... how is the tweecer? im havin probs getting my maf to read .6 at idle and car smells rich but reads lean.... was gonna take it down to have it tuned but the price for a tweecer is comparable... is it difficult to use/ worth the money.??

Its not as easy as people think, basic little things you can do are pretty easy but to do it right you need a dyno ortherwise you must invest in a wideband o2 and log than as well to make any progress. The ford eec strategy is literally as thick as a bible and alot to take in. Also I would opt for the quarter horse since you can make on the fly changes, tweecer is dated at this point if your going to venture into it.

Back to my topic the only thing I can think of is when i had the car painted i noticed the condensor has some overspray on it and it wasn't in great shape to begin with, is it possible this thing is't cooling or creating hot spots? Im going to thermal test some spots today with the infared.
 
thats not going to make your car overheat. at most your a/c wont be as cold as it could be.
I am currently chasing a grounding/wiring issue where my car runs at a normal temp but as soon as I turn on my headlights my temp gauge spikes to the top. turn the lights off and the needle drops where its supposed to be. just food for thought.