AC compressor causing overheating?

Status
Not open for further replies.
Joined
Oct 3, 2008
Messages
4,851
Location
Kuwait
This is the '01 Grand Marquis. The engine, transmission and differential were all rebuilt 12,000 miles ago and every cooling system component is brand new OEM, including a high flow water pump designed for the 4.6L 32-valve found on Lincoln Navigators. The only system that was left untouched was the AC system, which I haven't had any problem with. Also worth mentioning, I am running Steeda underdrive pulleys (crank and water pump only) with a 180 F thermostat and my cooling fan is configured to come on full blast at 206 F. Coolant ratio is 30% G13 to 70% distilled water. A couple of weeks ago I noticed a continuous, fast phased, rapid ticking/clicking noise from the compressor when the AC was on. The ticking went away when the AC was turned off. There were no issues with the AC and pressures were normal at the time. The other thing I noticed was fluctuating rpms at idle. Now I do have custom Stage 2 camshafts, but at idle the rpms will fluctuate up and down like a bad IAC valve, as if the PCM is trying to compensate for something like an air leak to keep the engine running. No vacuum leaks and I threw on a brand new Hitachi IAC valve on there less than 5,000 miles ago. Didn't make a difference between that and the "old" Motorcraft branded Hitachi that was replaced when the engine was out 7,000 miles earlier. No serious heating issues for the first 15 minutes or so of the drive yesterday, but monitoring coolant temperature on my ScanGuage-II, after 30 minutes or so it would go past the 206 F point the fan is supposed to come on full blast. Ambient was 108 F and you could hear the fan running continuously for dear life. It went all the way up to 222 F, unless you turned off the AC, when it slowly started to drop. If you dump it in neutral and rev to about 1,500 rpm, coolant temperature will start to drop, but rarely below 206 F. Even with the AC not running, it'll not drop below 206 F. Driving on the highway, regardless of whether the AC is on or not, you're looking at 211 - 215 F, lowest being 209 F. If the AC is on, it'll hit 218 F and keep climbing until you kill the AC. When the AC is running, it doesn't blow as cold as it used to and I'm thinking there might be a possible leak in the system. The unit was serviced 6 months ago, and there were no leaks or concerns at the time. Regardless, I will check the system pressure. The fins on the radiator and condenser are both squeaky clean. No leaks in the cooling system and coolant is up to level. For experimental reasons, I was thinking about putting the OE water pump pulley to see if it makes a difference, but I have a feeling that may not be the issue. Although I will be checking pressures first, given the ticking noise I was hearing from the compressor, does this sound like a bad compressor clutch that could be dragging down the accessories and causing the overheating? I have heard of clutch pulleys wearing down and causing the compressor to seize and prevent the engine from turning over, but never had it happen to me.
 
Joined
Dec 18, 2016
Messages
809
Location
United States
I would suggest trying to take the under drive pulleys out of the equation. I know typically they cause no issues, but at 108 Degrees ambient, you might need that extra flow from the water pump. When the Ac Is clicking is the clutch actually cycling on and off?
 
Joined
Oct 9, 2004
Messages
13,094
Location
Cincinnati, OH, USA
It's never below freezing in Kuwait-why not use Water Wetter and distilled water, along with a new thermostat, and see if that helps? I see you replaced all cooling system parts, but any chance the lower radiator hose is collapsing/getting sucked partially closed by the new high capacity WP?
 

AVB

Joined
May 20, 2012
Messages
1,460
Location
Georgia
Originally Posted By: MParr
Try a 50/50 mix and remove the thermostat and see what happens. Did you put on a new radiator cap?
Water cools better than antifreeze, going from 30/70 to 50/50 will not help cooling. It sounds like you need more air flow, the a/c condenser dumps heat into the radiator. The cycling of the compressor could be due to over pressure because the condenser is not shedding enough heat.
 
Joined
Sep 2, 2005
Messages
9,073
Location
MIchigan
Originally Posted By: AVB
Water cools better than antifreeze, going from 30/70 to 50/50 will not help cooling.
True.....but 50/50 gives you better corrosion protection.
 
Joined
Sep 17, 2002
Messages
5,470
Location
Lakeville, MN
So is there a mechanical fan clutch on this car? Plus an electric fan? Or just electric? If there is a mechanical clutch, I'd ditch the underdrive pulleys and see if it makes a difference. At an ambient temp over 100, it may be you are on the edge of what he cooling system can deliver before any modifications. Second, if you changed the mechanical clutch (if one is present), try another one. I've had bad ones out the boxes before. If its been switched from mechanical to all electrical, doe the electrical fans deliver the same cfm? I'm not familiar enough with the setup, but on my modular powered tricks, I've seen similar coolant temps, but I was driving up multi mile 6+% grades at 70+ mph in 90+ degree temps. The fan clutch made the fan sound like a Mack truck...
 
Joined
Sep 27, 2015
Messages
4,574
Location
USA
The first post notes that the temperature stays above 206 while idling in 108 ambient-- even with the A/C off. So the OP is on a goose chase thinking the A/C is somehow faulty. A car that overheats with A/C on is still very close to overheating with A/C off. The high flow pump combined with underdrive pulley seems like a zero sum game. The water flow of any centrifugal pump drops off severely at low rpm. Really agree with the others to go back to stock pulleys considering that it is not a track car, the application requires idling in traffic in desert heat.
 
Last edited:
Joined
Aug 15, 2006
Messages
10,060
Location
Central Washington
I agree, try the stock pulley on the pump. Its like a 20 minute swap. It might be high flow but it still needs to be spun to get any work done. Also, make sure the radiator cap is in good condition (test it with a pressure adapter) And make sure the plastic guides under and around the radiator are present and in reasonably good shape. Above 40mph the fan wont come on, it relies on air being forced through the radiator and those plastic guides are critical.
 
Last edited:
Joined
Jan 22, 2011
Messages
7,886
I wouldn't have installed that type of water pump.I have heard of problems when the coolant is traveling to quickly in the cooling system and causes issues. I would go with the pump and pulley for that vehicle.I would believe your belt would be burning up if the compressor had issues like that.
 
Last edited:
Status
Not open for further replies.
Top