aha! coolant system issues

[xplorernewb]

OK, so my last posts were focused on the heater core, as i thought that was the problem... but it is not. i replaced the heater core (and the leak followed by my idiot self being not very observant). but now im noticing that when the ac compressor clicks, i get the sound of a bad bearing somewhere, and it puts a slight drag on the engine when driving. when the bearing sound chimes in, i can hear it in the heater core for a second and it dies off. also, theres a single bubble sound coming from the heater core as soon as it clicks.

so far ive checked the fan. it doesnt wobble, theres a significant amount of resistance. i can grab the fan and push it, and it'll stop spinning as soon as i take my hand off of it. good?

2nd, checked thermostat. it opens and closes as it should

no leaks, not even the weep hole.

so i guess my question is, could my ac compressor be causing my temp to fluctuate due to the drag it puts on the engine? or do you think its putting drag on the engine due to a bad bearing in the water pump?

 

[xplorernewb]

BTW, it never overheats. it only rises to the N and drops down to just above the cold line

 

[Maniak]

The A/C does 2 things.. One, it is a drag on the engine but not that much... (10-15hp are the #'s I've seen)..

2nd, it is compressing the refrigerant which means it gets hot. It puts that hot refrigerant into the condenser up front which is in front of the radiator. The heat from the condenser needs to be pulled away, just like heat from the radiator needs to get pulled away...

If you are at idle (not moving) the fan is doing all that work and thanks to how the fan clutch and thermostat work the engine temp can and usually does move around some. If you overload the cooling system (bad fan clutch, poor condition cooling system) sitting at idle with the a/c on can get the vehicle pretty hot.

Right now, it doesn't sound like you have a problem with the cooling system.

Now, for the noise you hear with the A/C on.. It does make noise (it is compressing refrigerant) but you really shouldn't be getting a bearing noise when it is engaged. If you are, the compressor is probably going bad.

~Mark

 

[xplorernewb]

it makes that sound when the ac is off as well....

 

[xplorernewb]

so, does the ac clutch not supposed to engage when the ac system is off?? cause it clicks on and off every other minute or so when the ac is off, heaters off or on.... maybe a freon leak? and that would explain the bubble sound, and bearing sound?

 

[Maniak]

Hrm..

If it doesn't change with the clutch engaged or not (a/c on or off) you need to be sure it is coming from there first..

Use a piece of hose, or long extension and put it against the a/c compressor (when the clutch is off) and see if the noise is coming from there..

If it is, most likely you are loosing a bearing. It can last a week or many years.. you just can't tell, but you will know when it is getting worse (assuming it isn't really loud now).

It's been a while since I've worked on the fs10 compressor (other than just swapping one) BUT I "think" you can change the a/c clutch bearing without opening the system. IF it is the rear bearing you have to change the compressor which means opening the system which for most people means taking it in to get worked on.

~Mark

Edit: I just noticed your new question.. No, when the A/C and Heater system, and defroster system is off the a/c should NOT be engaging the a/c clutch. If it is, you have an electrical issue too.

 

[xplorernewb]

ok that makes sense. i think im going to bypass the air conditioner to see if it stops.

i read on another forum that if there is a leak in the condenser or actuator or whatever, the system will try to recharge and that is why the clutch engages and disengages? cause it thinks it needs to charge? is that true? knowing my luck, there'll probably be a leak and a bad bearing ha

 

[Maniak]

The A/C clutch only engages when it get power across the coil @ the A/C clutch. You can disconnect the electrical connector at the A/C clutch to make sure it never tries to turn on.

There are safety (low pressure only on a 1st gen) switches that will interrupt the signal which is why when you turn "on" the A/C from the switch in the truck that the compressor may "cycle" on/off. It is being told to turn on by the switch in the truck but the lower pressure switch is detecting low pressure (low charge) and that turns off the compressor. One the pressure rises (equalizes) it turns on the compressor again.. Rinse and repeat.

If you have the A/C turned off (defrost turns it on too) from inside the vehicle then the A/C clutch should never engage. If it does you have other electrical issues..

So, in short, If the A/C system is turned off it should never engage the a/c clutch.

If the A/C system is turned on the A/C clutch should engage BUT it can cycle due to safety switches ( I'm almost positive the 1st gen doesn't use a thermostat to turn off the compressor too).

~Mark

 

[xplorernewb]

hmmmm ok thanks

 

[xplorernewb]

yup unplugged the ac compressor and problem solved. guess ill be putting a bypass pulley on that soon. i was noticing some cold air though, behind the heater core.. maybe the door is just stuck open. ill have to investigate some other time since its not that big of a deal at the moment