F150 overheating issue with the ac on.

[AdRock]

'95 F150 5.0 2wd

I know the first thing everyone is probably going to say is the fan clutch. There's not fan clutch, I have a '95 Thunderbird fan on it with a Flex a lite controller. I've also had 3 different fans on it. 1st was a Taurus fan mounted inside the stock fan shroud, 2nd, was a T Bird fan with the Ford F4SH-8k621 motor in it, 3rd was a T Bird fan with a Siemens PM9027 motor in it which is supposed to be more powerful than the F4SH motor, both of those were mounted directly to the radiator.

A little info. New ac compressor, new drier, new (RED) orifice tube. Reman 5.0 long block with about 4k miles on it. New water pump, new thermostat, new radiator. Now, outside temps have been in the upper 90's lately so it's been worse than it was but it's been an issue for a while.

When running down the highway with the ac on all is fine if I keep the rpms under 2k. If I run it hard to pass or speed up the engine temp starts to creep up. I hit it for a few seconds and the gauge creeps up a little and stops, but stays there. Then if I hit it again it will creep up a little more, then stay there. It never drops back down. The fan is constantly running on high speed. If I turn off the ac the temp will still hold at wherever it's at with the fan still running. The temp will drop if I come to a stop and sit for a few minutes.

If I don't turn on the ac at all I can run the truck hard and it won't get too hot. But the fan will still come on.

Another piece if info, the high side line on the ac gets extremely hot.

So I'm thinking that this could be a combination of issues. Ac high side getting too hot causing the air coming to the radiator to be much hotter than normal, the fan isn't pulling enough air, possibly a blockage somewhere in the ac, possible blockage in the cooling system, etc.

I have my thoughts on where to start but wanted to get others opinions on this that might bring to light something I haven't thought of yet.

[Baba Ganoush]

Which controller are you using?

It sounds like not enough air movement, which a fan running at speed can do but that's an odd problem.

[AdRock]

I'm using the Flex a lite 31165 controller. It ramps up the speed so it doesn't hit the electrical system with a big amp spike on start up. I've ensured that it's putting out the full 12v when it should be.

[SC457A]

A/c on, will add a lot of heat in front of the radiator. High side of A/C at 250+ psi, with freon in a gas state is hot! Air flows through the condenser (while absorbing heat and then through the radiator). At highway speeds, the new parts should be plenty. Usually low speed overheating is a fan issue. However, if the fan and the shroud do not let enough air flow at high way speeds, that can be another issue.

This is of course assuming the temp sender and temp gauge are working correctly. Also assuming the reman motor was not bored over to make cyl walls thin....

[asphaltjunkie]

Have you verified that the coolant is actually getting hot, or just trusting the guage? It's possible the sending unit is giving you false readings.

You also listed all the things that are new, but I didn't see a new radiator cap listed. If it's not holding enough pressure, it can cause the coolant to boil, and that's no bueno.

I've heard that the best e-fan swap for this gen F-150 is the dual fan from around a '98 Contour. From what I've read, it's a direct bolt in (supposedly) and puts out something like 3600cfm. Might be something else to look in to.

[Baba Ganoush]

That's a good controller, I use the same one and utilize the on/neutral/off override switch and dual contour fans. Ice cold ac.

Radiator cap is a good thing to check. Sticky thermostat? With all the new parts I'd still suggest you test each one. Make sure you have good fluid and air movement and get temp readings off various areas of the engine.

[AdRock]

Have you verified that the coolant is actually getting hot, or just trusting the guage? It's possible the sending unit is giving you false readings.

You also listed all the things that are new, but I didn't see a new radiator cap listed. If it's not holding enough pressure, it can cause the coolant to boil, and that's no bueno.

I've heard that the best e-fan swap for this gen F-150 is the dual fan from around a '98 Contour. From what I've read, it's a direct bolt in (supposedly) and puts out something like 3600cfm. Might be something else to look in to.

The coolant is getting hot. I'm trusting the gauge right now but have an aftermarket gauge waiting to go in whenever I get a new instrument bezel so I can mount it.

The radiator cap is good. I have a Snap On tester from when I was still working as a tech. It's a 13lb cap and held till 13.5lbs. I haven't seen the Contour fans used. I'll take a look at them. I wish I could find a good Mark Viii fan with the White connector but they are few and far between. I've also heard that the 2010 F150 dual fans pull like crazy.

[AdRock]

That's a good controller, I use the same one and utilize the on/neutral/off override switch and dual contour fans. Ice cold ac.

Radiator cap is a good thing to check. Sticky thermostat? With all the new parts I'd still suggest you test each one. Make sure you have good fluid and air movement and get temp readings off various areas of the engine.

This weekend I hope to have time to flush the system. I plan to pull the thermostat out and check it on the stove. I also bought a Motorcraft water pump a while back from Tasca parts and plan to put that on and see if the flow gets better.

[Baba Ganoush]

I've had numerous bad thermostats right out of the box. Stay away from the Fail Safe brand.

Also, make sure your serpentine belt is spinning the water pump the right way! That's easy to overlook on these motors.

[AdRock]

I've had numerous bad thermostats right out of the box. Stay away from the Fail Safe brand.

Also, make sure your serpentine belt is spinning the water pump the right way! That's easy to overlook on these motors.

I really only use Stant or Motorcraft thermostats. I've always had good luck with them. And on the water pump, I bought the new Motorcraft one because I have an uneasy feeling about the one from Advance that's on there now. I see flow in the radiator when the thermostat opens but it just doesn't seem to flow as much as I think it should. I could be wrong though. At one point I even trised to route the belt to spin the pump the opposite direction to see if the flow rate would change but could never get a routing that would work.

[JC316]

Have you tried cleaning the condenser? They can get pretty clogged up with dirt and bug guts. You need to get an IR thermometer or an aftermarket gauge. Those Ford gauges from that year are shit to say the least.

[AdRock]

I bought an Equus electric temp gauge [ame]http://www.amazon.com/Equus-8162-Electric-Water-Temperature/dp/B001QJBDJ6[/ame] Not the most expensive gauge but I know a few people that have had good luck with them. And it's small so I can mount it in the instrument bezel. BUT, I had the bezel off to epoxy one of the clips and it fell off the bench. Broke into pieces and is unrepairable. they're hard to find used cheap and new they're fucking expensive. So I don't have a spot to mount it right now but I'm going to run the wiring this weekend.

I cleaned the condenser pretty well when I had the engine and radiator out but I'm going to pick up some of the coil cleaner from best buy and see if it makes a difference.

[shumpertdavid]

It's possible that you could have a standard rotation pump on the truck if it were boxed wrong or guy grabbed the wrong pump, you would have to pull the pump and rear cover to check that. I would expect the issue to have started right after the pump was installed if that were the case.

[jyro]

sounds like you're using an electric fan, A pump mounted fan moves 3x as much air.

[0393gt]

You guys need to make sure you have that plastic air deflector under your radiators. It makes a huge difference. My 86 gt didn't come with one from the factory, but I put one on and it drastically dropped my temps with the ac on, driving or idling.