88 dakota gets hot

[cwkerr007]

I'm currently changing the motor in my 88 it was v6 auto and before I took out the motor I upgraded the cooling system and charged the r12 system with 134a and vacuumed it and put new oil and it would freeze you out for 1 summer then the comp died but even with 3core aluminum rad and a hayden fan and a clean system if you run the a/c in july in traffic it would overheat ONLY if you run the a/c. So any suggestions for a solution to fix this while I'm in the middle of my motor change?????

 

[Professor Fate]

Just a thought-
If the compressor was dying, it could have been creating excessive drag every time the compressor switched on, making the engine work harder- generating more heat. Since the ambient was already hot (that's why you were running the AC, right?) it wouldn't take much to push the little V6 over the edge.
Only other option I can think of is that the aluminum radiator isn't doing it's job.

 

[RustyRatRod]

Does it have an AC condenser fan?

 

[cwkerr007]

No it's an 88 there isn't anywhere to put one I had to cut some of the rad support to even put the oversized rad in it but that would have probably solved the problem but at this point I may duct tape me one in front of the grill . Lol

 

[RustyRatRod]

No it's an 88 there isn't anywhere to put one I had to cut some of the rad support to even put the oversized rad in it but that would have probably solved the problem but at this point I may duct tape me one in front of the grill . Lol

What brand radiator?

 

[cwkerr007]

It's just an ebay 3 core aluminum it cools it great, doesn't have any leaks just can't keep up with the a/c goin . I just don't get it I had a 64 valiant that had a s6 in it. I took it out put a tunnel ram 340 in it left the little 2 core rad in it and didn't put a thermostat in it just to be sure I wouldn't have an overheat during break in and it ran so cool that I put a different carb on it thinking something was wrong with it cause it wouldn't idle and I put a 180 stat in it problem solved so why does this dakota run so hot ? I took out the stat and it still runs at 180 so I put it back in and it runs at that temp wether your pulling a load in july or cruising downhill in January and you can run thr a/c unless it's over 93ish and your in city traffic.

 

[cwkerr007]

I am wondering if I may have not done the proper things necessary when I changed the r12 to 134a . I read a thread in a forum the guy was explaining about the flow of the r12 system in first gen dakota is completely diff than the 134 and if you convert it the compressor doesn't get enough oil with it converted and won't hold up. And the one summer that it did work it was extremely cold and I am no a/c guru and my philosophy is if the compressor dies replace it all and start fresh and that has always worked for me but in this case I'm starting with a design flaw and I wonder if that might have caused the core to overheat? Cause I never heard of 134 getting colder than 12 and seams that if it gets colder wouldn't it also get hotter ?? I wish I would have gotten a temp reading from it before it died. What do ya'll think about this theory ???

 

[Kendog 170]

Not as much flow with a 3 core. 2 Cores flow more air. Might be just enough lack of flow when you use the A/C? I have a 3 core in my RB 500 stroker and it struggles a bit when really hot from this in traffic. (I believe)

 

[Bobzilla]

I'm currently changing the motor in my 88 it was v6 auto and before I took out the motor I upgraded the cooling system and charged the r12 system with 134a and vacuumed it and put new oil and it would freeze you out for 1 summer then the comp died but even with 3core aluminum rad and a hayden fan and a clean system if you run the a/c in july in traffic it would overheat ONLY if you run the a/c. So any suggestions for a solution to fix this while I'm in the middle of my motor change?????

If you are running hot only while sitting still or in stop and go traffic it should be an airflow issue across the radiator. What fan arrangement do you have? You need to have a factory style fan and fan clutch arrangement with a shroud that fits the radiator nicely. If you have a factory style setup the fan clutch may be worn out. They are supposed to "grab" harder and pull more air when they get hot. Some of the aftermarket fan clutches are tighter than originals and pull more air all the time, but that reduces fuel mileage a little.

If you put gauges on the air conditioning you can determine if it's running too high of pressure on the high side. If it's getting much over 250 psi on the high side the temperature will be getting too high as well. But if there is an airflow problem this will cause the pressures to be higher as well. So put a household box fan in the front of the truck on high speed, sitting at idle with temperature climbing too high, and see if it helps cool it back down.

 

[Demonracer]

Are you sure the temperature sensor is compatible with the gauge? If it isn't, it could be giving you a false reading.

 

[cwkerr007]

If you are running hot only while sitting still or in stop and go traffic it should be an airflow issue across the radiator. What fan arrangement do you have? You need to have a factory style fan and fan clutch arrangement with a shroud that fits the radiator nicely. If you have a factory style setup the fan clutch may be worn out. They are supposed to "grab" harder and pull more air when they get hot. Some of the aftermarket fan clutches are tighter than originals and pull more air all the time, but that reduces fuel mileage a little.

If you put gauges on the air conditioning you can determine if it's running too high of pressure on the high side. If it's getting much over 250 psi on the high side the temperature will be getting too high as well. But if there is an airflow problem this will cause the pressures to be higher as well. So put a household box fan in the front of the truck on high speed, sitting at idle with temperature climbing too high, and see if it helps cool it back down.

It has a hayden electric i instaleed after putting a generic electric on it. I would go with a solid fan but I am installing a 440 in it and there will be no room for it. Your fan idea is my ticket to diagnosis and as far as the psi of the system I won't know that till I install the engine and I wanted someone with prior knowledge to answer about whether I am suppose to change the design of the system so I could try to find one while the motor is out. And thanks for the time and great thought's on this I will let ya'll know what the prob is when I find it.

 

[cwkerr007]

Are you sure the temperature sensor is compatible with the gauge? If it isn't, it could be giving you a false reading.

I have the factory gauge and the fan sensor and since I started having the problem I carry my digital therm I use on several different applications and it is showing the same as the gauge and I've had the truck fo several yrs and I can tell when it is hot just from the reaction of the tbi the engine will run differently. And it will never overheat under any circumstances if the a/c isn't on. Thanks for your thoughts though cause I'm not past being absent minded and forgetting to check the basics and the small things. I'm 60 and been stupid 55 of those lol

 

[cwkerr007]

Not as much flow with a 3 core. 2 Cores flow more air. Might be just enough lack of flow when you use the A/C? I have a 3 core in my RB 500 stroker and it struggles a bit when really hot from this in traffic. (I believe)

Now you have enlightened me! The 3core is a much tighter airflow core than I have seen in oem rad's. You may have touched on the issue cause I remeber my valiant being transparent as in you could see through the rad almost I do know the tubes were spaced farther apart as to let air flow through easier. I'm going to find one of the 2core wide tube type rad I think you have touched on the issue I'm going to do a smoke test on the rad that is in it and one on a wider core oem rad and see if that is where my cfm's are going too . Thanks for your thoughts I'm going to try that today and will get back with you.