Air Conditioning and Coolant Temp question

[from6to8]

I took the Cobra for a pretty decent drive yesterday, outside temps 86 degrees, and decided on the way back to roll up the windows and turn on the AC. Noticed that my coolant temps which generally sit around 200-205 on a hot day got up to 218. Was nervous about this and shut off the AC and rolled the windows back down. This leads to a few questions...

1. In my main build thread someone mentioned that once the AC is charged, you need to disconnect the battery for like 30 minutes, then reconnect it and let it run 5 minutes no AC and then an additional 5 min with AC on MAX so the PCM can learn to idle with the AC running. I admittedly have not done this since charging the system and if I turn the AC on at idle the rpm's go up and down pretty erratically. Could this coolant temps be caused by the PCM not raising the idle enough, causing the water pump to run slower with the additional load? This happened in town with lots of sitting at stop lights and in traffic?

2. Could this be caused by the system still being on the low side of charged, requiring the compressor to run more frequently that it should?

3. Is this normal and I'm worried for nothing? I researched the coolant temps for the SN95 Cobra and saw a lot of posts saying this is potentially normal especially with AC in stop and go traffic.

hey man an issue I'm having brings me to this thread and I'm just getting started reading loll. I hope by the time I'm at the end I'll see what you've tried and what works/worked to remedy the issue. Mine will run warmer with the AC and eventually get up to 210-212. It seems to run around 205 207 ish on the highway or going about 60 mph but slowing down and kind of stop and go ish it'll go up to 210-212.

That aint even a problem at all to me though shit if I can get it to run cooler I'd want to. The issue is when I cut the car off say to get gas ect., when I start it back up it will idle fine for 15-20 secs then it will die if I don't play with the gas. Once I take off and get it up to speed and flowing it is fine and won't cut off at a red light unless I take off from a stop and only drive a few seconds or so till the next red light or even 1/4 mile or so and enough traffic to not have build up speed, it will want to cut off and likely will. It always starts back up though, though it sounds kinda muffled and almost kinda flooded and the pedal feels heavier/stiffer in that instance of taking off. But after that it's fine. I've checked a lot of stuff already.

my idle doesn't get erractic outside of after the 15-20 secs that it has been idling after I restart it under those circumstances mentioned above.....
NOt necessarily erratic but just will drop and cut off. And I don't even start the car with the AC on so it's not like it's under load initially. It's almost like it's too much fuel or something at that point once it's gotten to a certain temp, but then again ONLY once the car is turned off and turned back on, not cruising around.
AND ONLY IN HOT WEATHER.......

 

[cobrajeff96]

Check ground connections, clean any corrosion, make sure they are all tight. Run a code scanner on the obd port too.

 

[Mustang5L5]

Looks like he's got a converted V6 running an EFI 5.0. OBD likely won't work since he's likely got an EEC-4 computer so he'll need to pull codes using the older method.

But i second pulling the codes. Hot weather and hard to get a good idle on restart tend to be caused by a slightly rich condition. Could be a tuning issue, or could be senso related.

My 5.0 (similar combo) gets a little tempermental as well on hot restarts when it's hot out. Mine is tuning related which i am addressing now. I run 190-200 with the AC on.

 

[from6to8]

Check ground connections, clean any corrosion, make sure they are all tight. Run a code scanner on the obd port too.

I really don't think I have any of those issues but I'll look over things. Visually I definitely don't see anything that caught my eye in that regard. I mean the car runs good and I'd think that if those were issues I'd have issues in other weather conditions as well and year round even if intermittent.

and obd 1 so won't be able to scan with a tool. I have recently when diagnosed the fan coming on at start of car did a koeo and koer test. It was the Ect connector that needed changing.

 

[from6to8]

Looks like he's got a converted V6 running an EFI 5.0. OBD likely won't work since he's likely got an EEC-4 computer so he'll need to pull codes using the older method.

But i second pulling the codes. Hot weather and hard to get a good idle on restart tend to be caused by a slightly rich condition. Could be a tuning issue, or could be senso related.

My 5.0 (similar combo) gets a little tempermental as well on hot restarts when it's hot out. Mine is tuning related which i am addressing now. I run 190-200 with the AC on.

well the engine out of my other car that got hit in 2015 was in the v6 car that I did the conversion on. It's currently in my 94 Cobra but 94 95's are obd 1 right and you can't hook up a scan tool to it correct?

190-200 in stop and go traffic as well? Mine will run with AC on it will average usually around 205 at most with stock radiator and a 180 here in hot and humid ass South Carolina lmao. After I check some stuff I will at last resort go to the tuner or send to him and let him make some changes. I had a recheck of the tune in January but at that time the ECT sensor , connector was an issue as the car was warm on the dyno strapped in while he did some checks but said it was showing colder. I'm pretty sure he said showing colder ( not on the gauge) but I guess on the laptop. I'm sure he did'nt say it was showing warmer lol. But he said check the Ect and connector so when I got back home that's what I did.

Thing is the same situation did it in the other car as well , though it is the same pc/tune out of the other car. Even had a fluidyne radiator on the other car but it had a slight leak. Maybe that loss of pressure was an issue that would cause it to run a little warmer. The stock radiator in now wasin my barn since maybe 2003 or 2004 and maybe all of that time it even though it looks new and I flushed it out even though it wasn't dirty, maybe the heat in the barn all of those years till 2021 did something to it. But like I said I do not have an over heating issue it just gets warmer with AC on only and in hot weather...

 

[Mustang5L5]

well the engine out of my other car that got hit in 2015 was in the v6 car that I did the conversion on. It's currently in my 94 Cobra but 94 95's are obd 1 right and you can't hook up a scan tool to it correct?

1994 and 1995 V6's were OBD2. Both the V6 and V8 cars had the same dash harness so the V8 cars will have the OBD2 connector. But it won't work in the V8 cars as they are still OBD1/EEC4. The engine harness is different and the older T4MO won't have the OBD2 capability. SO in a V6-V8 swap, since the ECU is changed out, the OBD2 functionality is gone.

Just means you need to pull codes the EEC4 method.

190-200 in stop and go traffic as well? Mine will run with AC on it will average usually around 205 at most with stock radiator and a 180 here in hot and humid ass South Carolina lmao. After I check some stuff I will at last resort go to the tuner or send to him and let him make some changes. I had a recheck of the tune in January but at that time the ECT sensor , connector was an issue as the car was warm on the dyno strapped in while he did some checks but said it was showing colder. I'm pretty sure he said showing colder ( not on the gauge) but I guess on the laptop. I'm sure he did'nt say it was showing warmer lol. But he said check the Ect and connector so when I got back home that's what I did.

TBH, i rarely go past 195degrees. I'm running a 302 with TFS170 heads, ported Cobra intake, custom FTI grind cam, 1.6's, 24# injectors, exhaust and all that fun stuff. Cooling system is a 3-core brass radiator, 180* stat, and contour fan setup. I have a PWM controller on the fan and it's set to run at 70% speed unless i go over 200MPH, so pretty much it just runs at 70%. It will idle with the A/C on on a 95 degree humid day and not go past 195.

I do need a tune and was told this when I ordered my cam by Ed Curtis. I have a megasquirt setup on the bench ready to go in to address that. Just lack time. Really my issue is when it's HOT out (85 degrees or hotter) the car will surge and stall on hot restart. It smells rich and loads up. If i drive it smooths out. On a cooler day (under 75) it runs great all day long

Thing is the same situation did it in the other car as well , though it is the same pc/tune out of the other car. Even had a fluidyne radiator on the other car but it had a slight leak. Maybe that loss of pressure was an issue that would cause it to run a little warmer. The stock radiator in now wasin my barn since maybe 2003 or 2004 and maybe all of that time it even though it looks new and I flushed it out even though it wasn't dirty, maybe the heat in the barn all of those years till 2021 did something to it. But like I said I do not have an over heating issue it just gets warmer with AC on only and in hot weather...

It could potentially be an airflow issue or just a heat removal issue with regards to the added heat from the condenser when running the AC. It runs a little cooler on the highway and heats up at idle, so I wonder if the fan just isn't able to keep up. Whats the condition of the fins on the radiator and condenser? are any bent/clogged? Perhaps a vinegar flush on the radiator to remove some debris?

 

[from6to8]

1994 and 1995 V6's were OBD2. Both the V6 and V8 cars had the same dash harness so the V8 cars will have the OBD2 connector. But it won't work in the V8 cars as they are still OBD1/EEC4. The engine harness is different and the older T4MO won't have the OBD2 capability. SO in a V6-V8 swap, since the ECU is changed out, the OBD2 functionality is gone.

Just means you need to pull codes the EEC4 method.



TBH, i rarely go past 195degrees. I'm running a 302 with TFS170 heads, ported Cobra intake, custom FTI grind cam, 1.6's, 24# injectors, exhaust and all that fun stuff. Cooling system is a 3-core brass radiator, 180* stat, and contour fan setup. I have a PWM controller on the fan and it's set to run at 70% speed unless i go over 200MPH, so pretty much it just runs at 70%. It will idle with the A/C on on a 95 degree humid day and not go past 195.

I do need a tune and was told this when I ordered my cam by Ed Curtis. I have a megasquirt setup on the bench ready to go in to address that. Just lack time. Really my issue is when it's HOT out (85 degrees or hotter) the car will surge and stall on hot restart. It smells rich and loads up. If i drive it smooths out. On a cooler day (under 75) it runs great all day long




It could potentially be an airflow issue or just a heat removal issue with regards to the added heat from the condenser when running the AC. It runs a little cooler on the highway and heats up at idle, so I wonder if the fan just isn't able to keep up. Whats the condition of the fins on the radiator and condenser? are any bent/clogged? Perhaps a vinegar flush on the radiator to remove some debris?

Sounds like we are having a similar issue then and depends on where you are located and if you your area gets as humid as South Carolina. But yeah the surging and the stolen on hot starts and you know once I get going it's fine.. the tuner might be able to straighten out a few things you know in that regard with that harness connector being bad when he made some changes or try to make some changes in January the ECT sensor connector being bad.

So what I did find out today though is that it seems the low speed fan is not coming on and so doing some test I did not get power at the 10 amp fuse at the high current fuse panel but from my research and reading up it seems like they're supposed to be no power there I think only the 3.8 have power at that 10 amp fuse for the low speed EDF which is the low speed fan.

Also had a situation with my ccrm where the I stripped out the inside and so something was rolling around in there and it might have shorted something but when I checked all the fuses at the high current fuse panel everything powered up or light it up with the test light except that 10 amp fuse. So I'm going to check a few more things in the next few days I'm going to try another ccrm as I have a few more and I'm also going to put the other PCM back in. I also have another fan except that came out of the other car so a good bit of things to check to maybe kind of narrow it down some.

But when I checked the power at the fan plug because I was reading that the middle plug or the middle wire rather is the ground so I jumped the middle wire and then the first outside wire to the battery in the fan came on. When I went to the other outside wire fan did not do anything. So I know it's a possibility as well that the low speed fan circuit and that fan itself might be shot. Thinking at the low speed fan was coming on as it should then the engine would be cooler when the high-speed fan came on instead of the high-speed fan coming on at 190°. And if I'm driving and it already being at 190 without having been cooled by the low speed fan then that's just making the system work that much harder and those hot days and likely causing it to run a little harder with the AC on outside of highway driving where it should run cooler or would run cooler.

When I put the radiator in and 2021 even though it was sitting in the barn for shit probably 20 years but new I checked it over real good and there was no evidence of any dirt or debris or anything in it but I still flushed it out real good with the water hose. But I actually was going to go ahead and put another radiator on there anyway as I've been reading the stock radiators work just fine even with guys with 351s so I was going to do that and put another ECT sensor on there just to narrow those two things down as well. But the main issue now is getting this low speed fan situation worked out

 

[Mustang5L5]

Is the fan original to the V6?

If so, I believe they are high-speed only. Only the v8 fan had high and low.

I have a 94-95 V6 fan in my parts pile as I used to run it and it’s always been high speed only. Powering both the high and low speed wires only resulted in high only. Never low.

 

[ttocs]

when I lived in phoenix I had head/cam installed and had to have it dyno tested. Dyno testing in phoenix in july is not the best time to be doing it when it is 100 a 8am but that is when it was ready. I had a shop install the heads/cam and something was not right, the car would not cool itself well at all. He had two big fans blowing air in and even used a water mister to spray the rad to try and cool it off but he said it kept getting hot enough that it was taking timing out of the tune to try and cool itself but the temp gauge never got above the "M" in normal.

 

[from6to8]

Is the fan original to the V6?

If so, I believe they are high-speed only. Only the v8 fan had high and low.

I have a 94-95 V6 fan in my parts pile as I used to run it and it’s always been high speed only. Powering both the high and low speed wires only resulted in high only. Never low.

Now remember the car in question is now that engine out of the V6 that I did the conversion on is now in a 94 Cobra so all of the cobras wiring and fan and everything is specific to the Cobra it's still in the 94 in this car. So also I guess I was doing something wrong earlier because just a few minutes ago I went in and first I tested the fan out of my other car the wrecked 95 that was a V6 at first. I think I actually changed the fan and that other car at some point because I remember having an issue with the fan not coming on I can't remember if I changed the fan itself or the fan motor. So I'm thinking even if I change the fan motor then I'm pretty sure I would have gotten one for a v8.

But anyway when I test it that one first I tested the two outside wires and the fan came on. Then I tested the inside connection with the outside connection and the fan came on as well. I believe those are the only two scenarios in which the fan will work so I'm assuming that is half that has to be high in low speed.

So tomorrow I'm going to backtrack and I'm going to put on another ccRM and try it out and see if and actually both fans might have been coming on you know before respectively it's just that probably and as I've been reading, that's not really an audible difference much at all between the low and the high speed especially with a car that's not stocking you know not quite lol. So maybe the low speed fan was working like it should but also I need to find out at what temperature the low speed fan should come on even with the tune set to come on at about 190. If the if he has it coming on at 190 with a 180 stat is that the low speed fan coming on at 190 or the high-speed?

So I will proceed to check that tomorrow and then I also have another PCM as well as another or a new ECT sensor. Lassie is going to be checking the radiator taking it off checking everything making sure when I got the car painted that there was no over spray or anything that's clogging something up. So I will for shits and giggles flush it again and I think somebody mentioned vinegar a vinegar flush but anyway I will do that I might even take it and get it tested to make sure it's flowing like it's supposed to. And I did order another one from O'Reilly's actually that came in today so worst case is if I put the radiator back on and it's not doing or still doing the same thing I'll throw the new one on there and see if it's any different

 

[from6to8]

when I lived in phoenix I had head/cam installed and had to have it dyno tested. Dyno testing in phoenix in july is not the best time to be doing it when it is 100 a 8am but that is when it was ready. I had a shop install the heads/cam and something was not right, the car would not cool itself well at all. He had two big fans blowing air in and even used a water mister to spray the rad to try and cool it off but he said it kept getting hot enough that it was taking timing out of the tune to try and cool itself but the temp gauge never got above the "M" in normal.

Yeah and then the last thing is you know either I'm going to take the car to him and let him make the changes after that harness connector is fixed which it is since January when I went to him last, either I would do that or I will just go ahead and mail it to him let him make the changes tell him what the car is doing or explain again, and he said if he do that and there's no change he knows he need to go the other direction. So got a few things on my list to check and try and I believe I'll be able to get it eventually