2005 Navigator - Replaced nearly entire A/C system, still won't blow cold enough

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Re: 2005 Navigator - Replaced nearly entire A/C system, still won't blow cold enough

Postby Cusser » Tue Jun 06, 2017 7:14 am

AGrayson84 wrote:The fact that 2 months since the last recharge is still getting me the same 45 degrees coming out of the vents at times makes me really wonder if anything was ever really leaking to the atmosphere??? Thanks again everyone!!!!!!

I believe many would feel that 45 degrees is within specifications.
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Re: 2005 Navigator - Replaced nearly entire A/C system, still won't blow cold enough

Postby AGrayson84 » Tue Jun 06, 2017 6:21 pm

I guess the thing to keep in mind is that it will only hit 45 degrees sometimes. Some days it'll be in the 70's outside, and I'll be cruising down the highway with the A/C on full blast for 30+ minutes and still only see 48 degrees or so. And the amount of time it takes to get to 45 degrees, on the certain days this happens, is pretty crazy-- I have to be doing straight highway driving for at least 10-15 minutes usually. And we've barely seen any 85+ degree days yet. Most of the time, this struggle happens anywhere from 72 to 79 degrees ambient temperature. When it gets hotter out, I know the A/C will struggle to get to 50 out of the vents after highway driving. Let's not even talk about stop-and-go traffic lol. Last summer it could be 85-90 outside on certain days and the system couldn't even muster but 60 degrees out of the vents until I could reach consistent speeds. 60 degrees coming out of the vents on a 90 degree day is not cool haha.

So I did some more troubleshooting today, after only getting 53 degrees out of the vents when it was 77 outside this morning (can't tell me there's not something wrong there :)). I got home this afternoon and let the car idle for 10 minutes with the A/C on, after driving it home from work with the A/C at full blast. I was seeing about 50 degrees outlet temperature. I then clamped the hose to the heater valve, watched the outlet temp for over 5 minutes, and it didn't really change. I removed the clamp from the hose and temperature was still about the same. But I noticed that the heater valve was opening at times, when the A/C was set to full blast, and the outlet temps were still only 50 degrees. Made me wonder if that valve is opening up when it shouldn't be (not sure why it should ever open on it's own with the A/C at full blast, unless the evaporator was getting too cold... perhaps someone can shed some light on that). I zip-tied the valve shut and drove out to the highway for a few minutes. Outlet temps weren't any cooler, but I noticed the temps didn't increase while I idled, like previously. This may be due to the fact that the sun had just about gone done and the ambient temp was down to around 73 degree at the time. Perhaps the system was no longer struggling to maintain temps at idle?

I checked the recirc door and it seems to be operating just fine. Seems to be closing fully and all. But I did use my infrared temp gun and noticed that my front evaporator was at only around 60 degrees (I aimed it directly at the evaporator, through the hole where the blower motor control module is installed). Does that sound right, at all?

Something else I noticed is that with the heater valve tied in the closed position, if I leave the A/C and recirc button on, but set the temperature to 90 degrees, I am still getting 48 degrees coming out of the vents. Obviously there was not coolant running through the heater core to provide heat at that point, but shouldn't the blend door have completely blocked off air flow from the evaporator side of the plenum with the highest temperature set for the heat? Or not necessarily? Makes me wonder if the blend door isn't closing off the evaporator side of the plenum all the way, which also makes me wonder if it's not closing off the heater core side of the evaporator all the way when the lowest temperature (60 degrees) is set. Thoughts???

Lastly, I noticed only around a 10 degree difference between the two different lines connected to the condenser. Inlet and outlet, measure just a couple inches from where they connect to the condenser, were within 10 degrees of each other. This was at idle, and the engine bay was pretty warm, so heat soak may have contributed to the temps of the outlet line (that area was pretty hot from the engine). The condenser is brand new, and clean. The accumulator/receiver/drier (whatever you call it) is not freezing up either, so I don't believe there's a restriction.

What are the chances I didn't get all of the flush agent out of the system (perhaps some was stuck in each evaporator?) before I re-charged the system last year? I had removed the expansion valves and blew every last front and rear line clear including the evaporators, before installing the new condenser, receiver/drier, and compressor. Is there anything that would indicate that maybe there was still some flush agent in the system (ie: the evaporators) that I didn't dry out completely? I also had left the new receiver/drier open to the atmosphere for a few days when getting everything back together, not knowing any better at the time. Any way to tell if that is the problem? Unfortunately there is no sight glass on the drier. Thanks again everyone!

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