Mystery grinding noise after cold start

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

OP
OP
dixonk

dixonk

HMFIC
Joined
Oct 14, 2017
Posts
960
Reaction score
1,585
Location
Oklahoma
It's the ac compressor. One way to test is to change the remote start settings to use the last setting and not auto. Then turn on the face vents, heat to max, and make sure a/c light is off and front defroster is off. Remote start it and the compressor should stay off and not make the sound. Also, the truck must be cold for the sound, explanation below.



I chased this for awhile and replaced the ac pulley, clutch, and clutch coil. I found that once the compressor sits for a long period of time it gets stubborn to turn and this sound is the first jolt of it turning. I didn't replace the compressor so I'm unsure if a new one will make the sound go away or not and if this sound is a sign of the compressor going bad. However, I remember reading somewhere that a Ford engineer said it's due to the compressor being the lowest part of the system and as it sits all the freon/oil drains down to it and makes it have more stress when it first turns over.



Interesting. I had a feeling it was compressor because of the timeframe when the grinding happens. Everything is already running as far as engine goes and then it grinds very briefly.


Sent from my iPhone using Tapatalk Pro
 

Caliraptor2lit

Full Access Member
Joined
Nov 22, 2017
Posts
51
Reaction score
21
So, if I only drive my truck around one a week, should I make sure to use the AC every time? Or not at all? Is one way better for longevity?
 

Turk10mm

Full Access Member
Joined
Aug 11, 2017
Posts
130
Reaction score
65
Just so ya'll know, my 18 and another 18 in Houston are in the shop right now waiting on 4 replacement cam phasers for this. Its been 2 weeks. At least i'm riding around in a Lariat.

~1 second grinding noise at cold start only.

https://www.youtube.com/watch?v=iq6aUvB6fa0
 
Last edited:
OP
OP
dixonk

dixonk

HMFIC
Joined
Oct 14, 2017
Posts
960
Reaction score
1,585
Location
Oklahoma
Just so ya'll know, my 18 and another 18 in Houston are in the shop right now waiting on 4 replacement cam phasers for this. Its been 2 weeks. At least i'm riding around in a Lariat.

~1 second grinding noise at cold start only.

https://www.youtube.com/watch?v=iq6aUvB6fa0



On mine the grinding noise would occur after that video is finished not right at startup.


Sent from my iPhone using Tapatalk Pro
 

LXCoupe

Full Access Member
Joined
Apr 22, 2017
Posts
50
Reaction score
10
Just so ya'll know, my 18 and another 18 in Houston are in the shop right now waiting on 4 replacement cam phasers for this. Its been 2 weeks. At least i'm riding around in a Lariat.

~1 second grinding noise at cold start only.

https://www.youtube.com/watch?v=iq6aUvB6fa0

The Gen1 sound is a little different, it's delayed. The sound is a a couple seconds after truck is running.

A video of mine is below.

Clunk is at 9 seconds. It’s not as loud as it usually is and I think this is due to it not being very warm today. Btw truck had been sitting for at least a week.

 
Last edited:
OP
OP
dixonk

dixonk

HMFIC
Joined
Oct 14, 2017
Posts
960
Reaction score
1,585
Location
Oklahoma
The Gen1 sound is a little different, it's delayed. The sound is a a couple seconds after truck is running.

A video of mine is below.

Clunk is at 9 seconds. It’s not as loud as it usually is and I think this is due to it not being very warm today. Btw truck had been sitting for at least a week.




Mine comes on about the same time as yours does but it is a quick grind and then stops. Maybe a second or two but loud.


Sent from my iPhone using Tapatalk Pro
 

Swacer

Full Access Member
Joined
Dec 5, 2012
Posts
237
Reaction score
79
Location
PA
I had a grind the first time I turned the AC on this summer. Kinda took me by surprise. However, I can go a week or two now, and when the AC comes on, its quiet.
 
Top