Engine bay way too hot when AC is running (2 Viewers)

[Bryan062087]

I'm having an issue while my air conditioning is running in 70+ degree weather. When I use the ac, my engine compartment temperatures seem extremely high. The fan clutch is completely locked up, 100 percent of the time whether I'm on the interstate or driving around town. Additionally, the engine seems to lack power.

If I drive in the same conditions and temperature with the AC off, operation seems normal. The fan clutch locks up if I'm idling for a bit or in stop/go traffic, then unlocks once I start moving continuously at speed.

I was going to have my exhaust manifold ceramic coated in an effort to reduce engine bay temps, but I think most of the heat that's having a negative impact is coming from the air conditioning system.

When testing my a/c pressures, the low pressure side is around 30 PSI, and at the moment I'm unable to get a high pressure reading due to the adapter fitting not getting a connection on my r134a gauge set. I converted to r134 last summer and replaced the a/c compressor, condenser, evaporator, and expansion valve and have hardly used the AC until now. As far as I can tell, compressor operation seems acceptable with normal cycle timing. However, it is very hot to touch if it has been running for a while and the a/c condenser is hardly warm at all. I might have been having the same problems on the old r12 system too. I did not replace any of the a/c lines or use any flushing solvents.

Thanks for any help.

-Bryan

 

[OSS]

If it blows cold in the cab it'll blow hot in the engine compartment. Normal physics. That's why I never used AC even when it was 100° outside & why I eventually ripped it out of my car.

 

[red66toy]

If it blows cold in the cab it'll blow hot in the engine compartment. Normal physics. That's why I never used AC even when it was 100° outside & why I eventually ripped it out of my car.

How can you survive in the greenhouse 60 series with no AC and 100 outside? You would have to get a spatula to pry my corpse off the seat.

 

[Willard]

I agree with OSS. I took my 60 out for the first time in about 2 years. Since then I also rebuilt the AC and cooling system.
Today it was close to 87* but almost no humidity. My fan clutch was off and on my whole 60 mile drive.
AC was on max cold and #2 fan speed. Engine bay was hot, BUT my engine temp was hovering right around 180* per my mechanical temp gauge, driving @55mph it did not change much. dropped a little as expected.

So very normal, and as long as the engine is cooling correctly then what is the problem?

 

[red66toy]

I'm having an issue while my air conditioning is running in 70+ degree weather. When I use the ac, my engine compartment temperatures seem extremely high. The fan clutch is completely locked up, 100 percent of the time whether I'm on the interstate or driving around town. Additionally, the engine seems to lack power.

If I drive in the same conditions and temperature with the AC off, operation seems normal. The fan clutch locks up if I'm idling for a bit or in stop/go traffic, then unlocks once I start moving continuously at speed.

I was going to have my exhaust manifold ceramic coated in an effort to reduce engine bay temps, but I think most of the heat that's having a negative impact is coming from the air conditioning system.

When testing my a/c pressures, the low pressure side is around 30 PSI, and at the moment I'm unable to get a high pressure reading due to the adapter fitting not getting a connection on my r134a gauge set. I converted to r134 last summer and replaced the a/c compressor, condenser, evaporator, and expansion valve and have hardly used the AC until now. As far as I can tell, compressor operation seems acceptable with normal cycle timing. However, it is very hot to touch if it has been running for a while and the a/c condenser is hardly warm at all. I might have been having the same problems on the old r12 system too. I did not replace any of the a/c lines or use any of the flushing solvents.

Thanks for any help.

-Bryan

How hot is the engine running though? What is the coolant temp? Something definitely doesn't sound right.

 

[Bryan062087]

I agree with OSS. I took my 60 out for the first time in about 2 years. Since then I also rebuilt the AC and cooling system.
Today it was close to 87* but almost no humidity. My fan clutch was off and on my whole 60 mile drive.
AC was on max cold and #2 fan speed. Engine bay was hot, BUT my engine temp was hovering right around 180* per my mechanical temp gauge, driving @55mph it did not change much. dropped a little as expected.

So very normal, and as long as the engine is cooling correctly then what is the problem?

Coolant temps are around 190-200. The problem is that the lack of power is significant and the fact that the fan clutch operation seems abnormal (it always stays completely locked-meaning it never turns off once-even if the ambient temp/conditions are somewhat moderate for example high 70's to low 80's F and raining or during extended freeway driving). Additionally, its taxing on the engine and gives a marginal driving experience. I guess in essence I'm saying the problem I've tentatively identified is high under hood temperatures that seem to be related to the a/c operation.

 

[OSS]

I had a white cruiser with limo tinted black windows and a full length roof rack with a plywood floor. Windows always open. Inside of the cruiser never got above outside temps. The roof rack was key.

How can you survive in the

 

[tmxmotorsports]

Maybe the fan clutch is faulty. I run the ac in my 62 no problems 42 degree air coming out the vent over 90 outside truck temps normal fan clutch not engaged all the time. I can see where it would make yours lose power i got a jdm 3.0 for my daughters 4runner put it in left the fan clutch that was on because it felt tight drove it around aftrr putting the engine in was fine then i notice the fan roaring while driving sure enough it was completely locked

 

[Bryan062087]

Maybe the fan clutch is faulty. I run the ac in my 62 no problems 42 degree air coming out the vent over 90 outside truck temps normal fan clutch not engaged all the time. I can see where it would make yours lose power i got a jdm 3.0 for my daughters 4runner put it in left the fan clutch that was on because it felt tight drove it around aftrr putting the engine in was fine then i notice the fan roaring while driving sure enough it was completely locked

Thanks for the reply. I agree something is definitely off. I was thinking the fan clutch operation was a result/symptom not a cause, since it operates normally otherwise. And I can feel/sense a large difference in engine bay temperatures, although I'll try to get some exact temp readings soon.

 

[SteveH]

I would get an infrared thermometer and aim it at the oil pan, and top of the radiator on a hot day. The radiator should be lower than your t-stat temp (so it should read about 160-180). The other day when it was 85F, the side of my oil pan read 200F and my auto trans pan read 189F, both of which I consider normal.

Yes, the engine bay on a 62 seems like a blast furnace on a hot day, but verify your perceptions against real temps measured with a heat gun.
To preserve the life of underhood stuff, you might consider opening the hood after you park the truck on a hot day (if reasonable to do so) and let all that heat escape, rather than having it bake your rubber fittings and hoses. This works best in a garage, until you wife wonders why the hood is open, and how to close it

Steve

 

[89BIGBLUE]

Has the carb cooling fan been kicking on?
On a hot day, mine will fire up after parking it, and I can feel the heat blowing out of the passenger side fender vent, it’s not a hurricane type wind, but it’s moving air.

 

[Bryan062087]

Yes, the fan comes on but not every time.

 

[89BIGBLUE]

Mine does not come on every time either.
(I’m just happy it works!)

 

[FordPrefect]

Has any tried putting an electric fan on the condenser,
I was thinking of trying it this summer.
Mine is ice cold when driving but warms up a bit in traffic.

 

[Kleatus]

My AC really peters out sitting in traffic when it's hot out. The engine is also starting to get too hot under the same conditions. I am going to replace the fan clutch as soon as it shows up, and will go from there. I removed my old tranny cooler this weekend and found the area of the condenser behind it was plugged up with years of bugs and seeds and grime. That's been cleaned off, and a new cooler with a fan installed.

Has any tried putting an electric fan on the condenser,
I was thinking of trying it this summer.
Mine is ice cold when driving but warms up a bit in traffic.

 

[Bryan062087]

Have yet to get an infrared thermometer, but there is a huge difference in engine bay temps between running the a/c and not. Even the hood and hood prop are "burn your hand hot" after running the air conditioning. Additionally, the passenger side of the hood is the hottest area. I'm also getting a spike in engine water temperatures about 10 or more degrees. After idling for 5 mins without a/c, steady 180 degrees. Idling for approximately 5 mins with a/c running, about 194 degrees. I have a 180 degree thermostat and a mechanical water temperature gauge.

 

[Spike Strip]

Put some hood louvers in.

 

[scrapdaddy]

Spike,

That's what I was thinking, it needs to breathe a little. I have louvers in my 55 hood and I really thinks it helps a lot.

 

[Spike Strip]

I've got a pair that I intend (someday) to install in my 60... Really makes a big difference in keeping the engine compartment cooler by allowing it to vent.

 

[dmjay]

Put a diesel in it, they don't get very hot.