Fans Run After Shutoff... Normal?

G

garciapiano

Veteran Member
Joined
Feb 12, 2018
Location
Southern California
TDI
1997 Jetta TDI (1Z)
Hey guys,

I’ve noticed on hot days that the fans will run for a few minutes after shutting off the car. This has happened in several instances regardless of how hard I was driving the car, It appears to be a built in feature since the fans do eventually shut themselves off, although I don’t know what would be the benefit other than cooling the engine compartment. There is no after-run coolant pump. Is it normal and what are the conditions under which it will occur?
 
Mongler98

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
Just so you know you heard it from Not a newb!
Yea that's correct. It's to combat heat soak.
 
Mongler98

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
COLORADO (SE of Denver)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress) I moved so now i got nothing but an AHU in a garage on a pallet.
rocky raccoon said:
Mongo: I may be a newbie VW TDI owner but I assure you I am no newbie to Diesel and amateur wrenching.
Click to expand...
Just confirming you are correct. That's all. We dont know your history!
And its mongler, not mongo.
 
Steve Addy

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
garciapiano said:
Hey guys,
I’ve noticed on hot days that the fans will run for a few minutes after shutting off the car. This has happened in several instances regardless of how hard I was driving the car, It appears to be a built in feature since the fans do eventually shut themselves off, although I don’t know what would be the benefit other than cooling the engine compartment. There is no after-run coolant pump. Is it normal and what are the conditions under which it will occur?
Click to expand...
It's rare but the system is designed to come on independently if the control module senses increase in temperature for some reason. VW calls it the cooling fan after-run system.

TBH I've never witnessed the after run on any of my Mk3 or my B3V conversion although always assumed it was that way.

The after-run system has been around for quite a while.

Steve
 
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