Transmission Cooler Line Popped Out

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.

rdezs

Member
Joined
Nov 6, 2023
Posts
38
Reaction score
44
I just read the original post again. The tranny cooler portion of the radiator is not plugged. It was her upper transmission cooler line that popped out of the radiator.... The transmission fluid enters through the lower fitting and exits through the upper.... Was probably just a bad fitting. I've seen some really cheap aftermarket ones. That particular part really needs to be an AC Delco or genuine GM.
That means there's a cooling system issue. I'm banking on a large air pocket trapped in there.
 

j91z28d1

Full Access Member
Joined
Feb 28, 2022
Posts
3,222
Reaction score
4,001
just to add thou my service manual doesn't actually call for a vacuum fill on a ls. other cars require it, while it's not a bad idea to do, it's not a particularly complex cooling system. all is says is basically fill, idle till stat opens. turn off, wait till it cools off. top off reservoir and should be good to go.
 

89Suburban

Bull in the china shop
Supporting Member
Joined
Jan 10, 2013
Posts
15,328
Reaction score
42,702
Location
SE PA
just to add thou my service manual doesn't actually call for a vacuum fill on a ls. other cars require it, while it's not a bad idea to do, it's not a particularly complex cooling system. all is says is basically fill, idle till stat opens. turn off, wait till it cools off. top off reservoir and should be good to go.

I’ve hade to do a few 1-2K good revs to get the front and rear heater cores purged the last few times I had to do this. Always a good idea to have the interior heater on to confirm. I’ve showed a 210 temp reading with 0 heat coming from the heater.
 

houstontaylor

Member
Joined
Dec 4, 2017
Posts
86
Reaction score
93
This may not be the case with your vehicle but one time on my 2003 Tahoe the steering linkage was hitting the transmission cooler lines and causing damage. It turns out that one of the engine mounts was bad and allowed the engine to drop down with transmission cooler lines low enough to cause interference.
 

BMPNUGLS

Full Access Member
Joined
Apr 5, 2015
Posts
226
Reaction score
102
Location
Mid-MO
I’m betting a trans cooler port in the radiator still had a plastic cover or plug in the new radiator that wasn’t removed….which could be why your line popped off as well….it built up pressure and blew off. My first thought would be to check trans cooler fittings and make sure there is no obstruction and that you can blow through the trans cooler section of radiator w air….
 

Forum statistics

Threads
132,722
Posts
1,873,182
Members
97,551
Latest member
Westernstar8806

Latest posts

Top