Running R-134 question

[friskyfrankie]

Have the box it came in somewhere in my stash. Therefore, not sure of the P/N.

[Toploader]

I feel somewhat foolish in admitting how many years it took me to figure out why the blower motor would always slow down or quit completely when I would feed gas, and come back up when I eased off the pedal.

[friskyfrankie]

I recently put a new check valve, in my friend's car, and it worked for several months (yes, an OEM part). Now he is having an issue again so when I can get to it, I need to see where the vac leak is coming from. Hopefully, not the "new" check valve! He is having the same issue you had so perhaps the valve is again at fault? We'll find out eventually. cause his "coffee can" looks good but I need to see if it hold vacuum. ...

[Toploader]

I recently put a new check valve, in my friend's car, and it worked for several months (yes, an OEM part). Now he is having an issue again so when I can get to it, I need to see where the vac leak is coming from. Hopefully, not the "new" check valve! He is having the same issue you had so perhaps the valve is again at fault? We'll find out eventually. cause his "coffee can" looks good but I need to see if it hold vacuum. ...

Frank..............look carefully at the coffee can seams, they may look good, but push all over the top and bottom, the rust could have eaten through but not easily seen. That is how I finally discovered my can was rotted out.

[friskyfrankie]

Frank..............look carefully at the coffee can seams, they may look good, but push all over the top and bottom, the rust could have eaten through but not easily seen. That is how I finally discovered my can was rotted out.

Will do - I do have the Dorman version of it and it is plastic so unless it cracks, we're good. Just "another brick in the wall"!

[sly]

Motorcraft YG337 is that check valve.

[friskyfrankie]

Motorcraft YG337 is that check valve.

Never hurts to have the proper P/N - many thanks!!

[gadget73]

Thain, not on my '86 MGM with ATC. Every time I would feed gas the blower motor would either slow down or go off completely. Long story short, the bottom of the coffee can was rotted around the seams, and the vac tree on the dash was leaking. After I replaced both no longer a problem.

If its not in auto mode, vacuum has nothing to do with it. The fan has two ways of controlling speed on an ATC car. In auto mode, it uses one mounted on top of the blend door servo. When the blend door is near center travel the fan is in low speed, towards full hot or full cold its at high speed. The second is the switch on the dash. High is high, it will not change speed. The system defaults to defrost when there is no vacuum. ATC cars specifically get hot defrost when there is no vacuum. The fan isn't slowing down, its just moving to the windshield. If its in fan auto mode and you have it at full cold, the fan will slow down as the blend door swings towards hot but will speed back up as it gets towards full hot.

in non-ATC cars, the blend door is moved by a cable, and the fan speed is only controlled on the dash. It still uses vacuum to control where the air comes from though, so it will shift to defrost.

[friskyfrankie]

So if you are on High Speed (in a ATC car) and the fan speed drops on acceleration - what causes the issue since it is not a vacuum problem?

[Toploader]

Motorcraft YG337 is that check valve.

Yes it is.

[Toploader]

So if you are on High Speed (in a ATC car) and the fan speed drops on acceleration - what causes the issue since it is not a vacuum problem?

Thank you!!!!!!!!!!!!

[Toploader]

Well, my coffee can was rotted out, and I had additional issues with the check valve, replacing both of these items resulted in high fan even at speed, or when I stomped the gas to get trans kick-down. Before the two items mentioned were replaced, the blower motor would stop or slow down when I stomped the gas, or the car was in a state of high expressway speed.

[friskyfrankie]

I'll be checking both when I can. Got a check valve, on order and already have the plastic version of the "coffee can". Getting tired of chasing the same issue, every few months so hope they seal the deal!

[gadget73]

So if you are on High Speed (in a ATC car) and the fan speed drops on acceleration - what causes the issue since it is not a vacuum problem?

its probably not slowing down, just the air doors are moving and the air is coming from somewhere else so you don't feel it anymore. It also shifts from recirc to outside air, and that usually does add some restriction so a bit less airflow. If it is actually slowing down, it has to be some really goofy electrical fault

[friskyfrankie]

its probably not slowing down, just the air doors are moving and the air is coming from somewhere else so you don't feel it anymore. It also shifts from recirc to outside air, and that usually does add some restriction so a bit less airflow. If it is actually slowing down, it has to be some really goofy electrical fault

So, if the fan speed is not actually slowing down then what is or are the issue(s)? Assuming it is not a weird electrical issue I would think it has to be vacuum related.