Engine gets close to overheat with ac on

[Shran]

There should be some foam insulation strips on the sides of the AC condenser that sort of create a seal to direct air through the condenser and then through the radiator... if those are gone, the system efficiency will suffer. Check for a pile of leaves between the radiator & condenser as well. It might be worth pulling the radiator out and washing out the fins, they collect an incredible amount of dirt and crap that is hard to see.

Some trucks have additional air baffles behind the bumper and behind the grill that will direct air into the condenser. Yours should. Those will help a lot.

My Explorer and one of my Rangers were both getting uncomfortably warm with the AC on and both were missing the foam insulation. Explorer was missing the baffles (I think I took them out, but who knows.) I put new foam in there and replaced the baffles and both work perfectly now. The foam by itself made a huge difference. Air just sort of cavitates in there without it.

 

[Bunger317]

There should be some foam insulation strips on the sides of the AC condenser that sort of create a seal to direct air through the condenser and then through the radiator... if those are gone, the system efficiency will suffer. Check for a pile of leaves between the radiator & condenser as well. It might be worth pulling the radiator out and washing out the fins, they collect an incredible amount of dirt and crap that is hard to see.

Some trucks have additional air baffles behind the bumper and behind the grill that will direct air into the condenser. Yours should. Those will help a lot.

My Explorer and one of my Rangers were both getting uncomfortably warm with the AC on and both were missing the foam insulation. Explorer was missing the baffles (I think I took them out, but who knows.) I put new foam in there and replaced the baffles and both work perfectly now. The foam by itself made a huge difference. Air just sort of cavitates in there without it.

It has a new radiator and I cleaned out the condenser fins when I changed it. I saw the old deteriorated foam when I did the radiator. I can look into replacing that. Was there foam between the radiator and fan shroud also?
I just ordered a glow shift digital cause I'm going to install in place of the stock sending unit to see what my temps actually are.

 

[Shran]

Nope, just foam between the radiator & condenser. I added strips between the condenser & core support on mine as well but that part was not there from the factory.

 

[sgtsandman]

The only thing that I can see as an issue is the gearing with the tire size you have. The engine is working harder to turn those bigger tires. I can’t say so much with the heat issue on how much it effects it but I do know it will have an impact on your fuel mileage and probably is a contributor to your heat issue if not the main cause. There is a chart in the Technical Articles section called gears vs tires that shows the best gear ratio for best fuel economy, good over all, and towing and hauling. My guess is you would want to be in the middle.

For an example. My 1998 had a 2.5 Lima engine and a 3.45:1 gear ratio from the factory. The thing couldn’t get out of it’s own way and got about 21-22 mpg. I switched the axle to a 4.10:1 and got the same mileage but it’s ability to get around was greatly improved.

As another example, my 2011 came from the factory with 29” tires (235/75-R15) and a 3.73:1 gear ratio. I up sized the tires to 31”. The drivability of the truck before was ok but not outstanding. Mostly because of the hilly terrain I live in. After the tire switch, the truck can struggle on the steeper hills and sometimes on the Interstate. To get it back to where it was, I would need to change the gear ration in the front and rear axles to 4.10:1. The highway fuel mileage also dropped from about 22 mpg to 18-19. To get the truck where I think it should be for what I do with towing, hauling, and driving off road, 4.56:1 is a better fit. The fuel mileage probably won’t change but it will no longer struggle in certain situations anymore.

So, as a recap, I think you have too tall of a gear ratio for the tires you have and I suggest considering a regear to improve your fuel mileage and perhaps also help some with your engine temperature issue since the engine won’t be working so hard to get moving and keep moving.

Not a cheap solution but I think it would be the best solution for you.

 

[Shran]

Yeah the tire size and gears will put a hurt on things especially with an automatic. I would invest in a really good transmission cooler if you haven't already, that will keep your A4LD alive a little longer.

 

[Bunger317]

Yeah the tire size and gears will put a hurt on things especially with an automatic. I would invest in a really good transmission cooler if you haven't already, that will keep your A4LD alive a little longer.

way ahead of you. One of the first things I did. Hoping to do gears soon just need to save the extra cash for some lockers. Don't want to half ass it.

 

[RonD]

So new rad, water pump, and fan clutch seems OK

Does temp go up when you slow down with AC off?

If you can get an IR temp reader the condenser should only get to 140degF(60C) MAX, 120degF is more normal, on the inlet side(top), and drop 20deg or so across to the outlet side(bottom)
So cooler than warmed up radiator

 

[Bunger317]

So new rad, water pump, and fan clutch seems OK

Does temp go up when you slow down with AC off?
No it doesn't. Maybe


If you can get an IR temp reader the condenser should only get to 140degF(60C) MAX, 120degF is more normal, on the inlet side(top), and drop 20deg or so across to the outlet side(bottom)
So cooler than warmed up radiator

I've got one, I'll try that in a little bit when I run to the store for the Friday 12 pack.

 

[Bunger317]

So new rad, water pump, and fan clutch seems OK

Does temp go up when you slow down with AC off?

If you can get an IR temp reader the condenser should only get to 140degF(60C) MAX, 120degF is more normal, on the inlet side(top), and drop 20deg or so across to the outlet side(bottom)
So cooler than warmed up radiator

One line driver side top was 189 the passenger side lower was 161. I took the reading off the lines right before they go into the condensor because my trans cooler is in the way up front

 

[Bunger317]

So new rad, water pump, and fan clutch seems OK

Does temp go up when you slow down with AC off?

If you can get an IR temp reader the condenser should only get to 140degF(60C) MAX, 120degF is more normal, on the inlet side(top), and drop 20deg or so across to the outlet side(bottom)
So cooler than warmed up radiator

gauge is on M and upper radiator hose reads 205 lower reads 189

 

[Bunger317]

So new rad, water pump, and fan clutch seems OK

Does temp go up when you slow down with AC off?

If you can get an IR temp reader the condenser should only get to 140degF(60C) MAX, 120degF is more normal, on the inlet side(top), and drop 20deg or so across to the outlet side(bottom)
So cooler than warmed up radiator

Drove home with the AC off the temp dropped right back down to the N and never moved

 

[RonD]

Are you sure the fan clutch is working, with no fan you should get a 15deg drop in coolant temp, with fan deg 20-25deg drop


20deg drop on condenser is correct, but overall temp seems high, but not a full time AC guy
AC is effected by outside temps way more than coolant

205deg is OK not overheating should be about 1/2 on the dash temp gauge may be a tick over 1/2
230deg is overheating, that's about 3/4 on the dash temp gauge and time to shut things down

The N O R M A L doesn't help as all gauges are different, lol
1/4, 1/2 3/4 are OK
Most Ford Temp gauges have 205 as the 1/2 way mark
"Normal" warmed up operating temp is 190-195degF, so just below 1/2
If going up a long hill or pulling a load on a warm day, just above 1/2 is not a concern

 

[Bunger317]

Are you sure the fan clutch is working, with no fan you should get a 15deg drop in coolant temp, with fan deg 20-25deg drop


20deg drop on condenser is correct, but overall temp seems high, but not a full time AC guy
AC is effected by outside temps way more than coolant

205deg is OK not overheating should be about 1/2 on the dash temp gauge may be a tick over 1/2
230deg is overheating, that's about 3/4 on the dash temp gauge and time to shut things down

The N O R M A L doesn't help as all gauges are different, lol
1/4, 1/2 3/4 are OK
Most Ford Temp gauges have 205 as the 1/2 way mark
"Normal" warmed up operating temp is 190-195degF, so just below 1/2
If going up a long hill or pulling a load on a warm day, just above 1/2 is not a concern

I sure as hell can hear it. When I leave from a stop so I assume the thing is spinning at idle.
I just went out and tried to spin it and it'll go maybe an 1/8th of a rotation with a good flick

 

[Bunger317]

Could this be a issue with the heater core?

 

[RonD]

Could this be a issue with the heater core?

Usually not
Clogged heater core/hoses will cause temp to go up and down randomly, not related to RPMs or engine load
And never above 3/4 on the gauge
Heater core is fed from thermostat housing, so if flow is restricted it will cause coolant to heat up more in the housing and that opens thermostat more so temp drops and thermostat closes a bit, then repeats, so temp goes up and down on the gauge, but randomly because hoses or core are never completely block, unless you do it on purpose, lol