Main IndexAuto Repair Home Search Posts SEARCH
POSTS
Who's Online WHO'S
ONLINE
Log in LOG
IN









Search Auto Parts

ac causing overheating


  Email This Post



kansasman
Novice

Apr 9, 2016, 6:40 PM

Post #1 of 19 (1904 views)
ac causing overheating Sign In

I have a 2004 dodge intrepid 2.7 liter and it overheats only when I use the a/c, my mechanic can't figure it out. I have new hoses, new a/c compressor, new reservoir with new cap, new thermostat, new radiator, new twin fans, new water pump and timing chain, valve cover gasket and head cover gaskets, and it has been pressure tested and the coolant flow has been tested after new water pump was put in and it still overheats when running the a/c, does anyone have any more ideas how to solve this problem. oh yeah and new fans do come on.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Apr 9, 2016, 7:06 PM

Post #2 of 19 (1900 views)
Re: ac causing overheating Sign In

Sounds like way too much parts changing and not enough testing.

Do the fans work on both speeds?



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



kansasman
Novice

Apr 9, 2016, 8:32 PM

Post #3 of 19 (1891 views)
Re: ac causing overheating Sign In

They both were tested to work but I don't know if he tested for both speeds.


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Apr 9, 2016, 9:18 PM

Post #4 of 19 (1881 views)
Re: ac causing overheating Sign In

Does this overheat with the ac running while your cruising and/or sitting at a light? Is the engine actually overheating or could there be an electrical issue with the gauge?





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.


kansasman
Novice

Apr 9, 2016, 10:56 PM

Post #5 of 19 (1872 views)
Re: ac causing overheating Sign In

when I drive without ac the engine if norm, after driving with ac for about 5 to 10 minutes the guage rises up near the red and I quickly turn ac off and within 5 minutes the temp is back to normal


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Apr 10, 2016, 4:35 AM

Post #6 of 19 (1862 views)
Re: ac causing overheating Sign In


Quote
They both were tested to work but I don't know if he tested for both speeds.


I don't mean manually test the fan itself. Does the fan come on by itself when the temp rises and does it come on faster when the temp get real high?

Does the fan come on when the AC is turned on?



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Apr 10, 2016, 4:40 AM

Post #7 of 19 (1859 views)
Re: ac causing overheating Sign In

As HT asked and said does fan come on with A/C request alone - as in before radiator is even warm enough?
Also - said this too that you've replaced enough already for mistakes. Is/are fans blowing the correct direction? That would sure explain a lot,


T



kansasman
Novice

Apr 10, 2016, 10:39 AM

Post #8 of 19 (1840 views)
Re: ac causing overheating Sign In

fans blow correct direction, I got up this morning and started my car and fans didn't come on with cold engine then turned on max ac and fans still didn't come on with cold engine. once engine reached normal operating temperature then the fans kicked on but when I turn on ac it doesn't sound like it's going any faster.


kev2
Veteran
kev2 profile image

Apr 10, 2016, 10:44 AM

Post #9 of 19 (1835 views)
Re: ac causing overheating Sign In

I am fairly sur the fans are commanded ON with A/C ....
Have you had this scanned for codes as no fan with AC request should have been noticed By PCM...


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Apr 10, 2016, 10:53 AM

Post #10 of 19 (1832 views)
Re: ac causing overheating Sign In

What ambient temps is this doing this? If it doesn't need A/C or too cold it wont kick on and blow colder air.
The prolonged delay of fans when A/C is working and I mean compressor is working is normal for several vehicles but only when it's already cool enough for A/C to lower cabin temps which if warm at all doesn't take long to kick them on. You wouldn't notice fans can kick off at higher road speeds where airflow alone is enough and should cool both engine and A/C parts to work.


You've changed out a lot of stuff. Now I don't think fans come on when they are supposed to confused by the A/C somehow that they really should be ready to go but aren't? Not so sure why.
There's a chance a code is luking and bet fans are disabled and it really is running too warm/hot but would verify that as well with actual temp and what the car's gauge is telling you just to know,


T



kansasman
Novice

Apr 10, 2016, 11:22 AM

Post #11 of 19 (1829 views)
Re: ac causing overheating Sign In

monday I will see if the mechanic can check the Hi Lo relays to see if they are all good. The relays with lifetime warranty cost 16.99 each at autozone


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Apr 10, 2016, 1:42 PM

Post #12 of 19 (1816 views)
Re: ac causing overheating Sign In

Does this run hot while it is idling and the ac is on? If you're cruising 30 mph or higher the cooling fans won't be needed. The ram air provides plenty of cooling for the condenser and radiator.

Has this been wrecked? Are all the air deflectors and shrouds in place and not damaged? Is the condenser clear of debris? Has your mechanic compared scan tool data pid for ECT to the gauge to be sure they are reading close to the same?





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.

(This post was edited by Discretesignals on Apr 10, 2016, 1:48 PM)


kev2
Veteran
kev2 profile image

Apr 10, 2016, 2:01 PM

Post #13 of 19 (1809 views)
Re: ac causing overheating Sign In

good questions- but the answers are lacking.... CODES
If the AC kicks out for a pressure issue it will code*, if the system cannot switch low (series) to hi (parallel) cooling fan** guess what ? not to mention the HVAC module self test - just keep replacing - GTG


*P159x series
**P048x


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Apr 10, 2016, 4:21 PM

Post #14 of 19 (1802 views)
Re: ac causing overheating Sign In

OK, you really need a professional scan tool here. This system is equipped with a 3 wire pressure sensor that delivers specific pressures to the PCM.
You need to see if these pressures are actually correct.

You can also activate the fans from that tool also so see if the computer has control of them.

You need to stop guessing and throwing parts at it and let a professional check these things out.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



kansasman
Novice

Apr 10, 2016, 11:21 PM

Post #15 of 19 (1787 views)
Re: ac causing overheating Sign In

I usually turn on ac when going 70 mph


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Apr 10, 2016, 11:54 PM

Post #16 of 19 (1784 views)
Re: ac causing overheating Sign In

OK - If that's the usual habit and when it overheats it smack of an air flow problem thru radiator with is also a radiator (condenser) for the A/C.
This moves on to A/C controls as that's when this happens, The 3 wire switch that HT just mentioned is there to cut off the A/C with high heat or too much pressure.
This item is designed to let the controls for compressor and fan(s) run properly as part of the deal. You said this car waits for fans while observed if A/C is on till engine heat is high enough or too high.
What you need to know is if this is operating as designed or failing with the controls.


It's already been mentioned and VERY important. All those air shrouds and especially the air dam underside that's easy to knock totally off just parking are 100% designed for air to flow where directed by fan and or speed of car or both.


With any missing fans could actually stop air flow when running! Air packs under the car with no way to flow thru grille - got me?


It's already designed to know when fans help or are actually not helping up to causing low or no air flow by shape of the thing. Any changes or parts missing or improperly installed matter.


Other is with 3 wire high pressure switches some will jump or test with a test light or paper clip to charge A/C or check for what I don't know and blow the PCM controls for it which goes stupid on you. A Mopar exclusive. Guess FIAT will have to figure it all out now.
HT said and it's probably what you need now is a high end scan tool to see if it functions as intended which will be unique to that car. If not missing parts or improperly installed I just hope the right tool can point out the fault possibly now the PCM not a conclusion yet but now in the cards. Too much stuff has been thrown at this from the first post suggesting no attention to what was really the issue from the get go,


T



Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Apr 11, 2016, 2:09 AM

Post #17 of 19 (1778 views)
Re: ac causing overheating Sign In


Quote
Other is with 3 wire high pressure switches some will jump or test with a test light or paper clip to charge A/C or check for what I don't know and blow the PCM controls for it which goes stupid on you.


Definitely do not try that.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



kansasman
Novice

Apr 11, 2016, 8:34 AM

Post #18 of 19 (1764 views)
Re: ac causing overheating Sign In

I think I will take it to the dealership and have them check everything since they are most familiar with the car and then I will post on here what they found the cause to be so others who might be having the same problem will help them find a solution.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Apr 11, 2016, 8:51 AM

Post #19 of 19 (1761 views)
Re: ac causing overheating Sign In

Good plan



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.







  Email This Post
 
 


Feed Button




Search for (options) Privacy Sitemap