Oil cooler line size with K5L heavy duty cooling

[kyleag89]

As the title says I have a 2011 sierra 1500 with the heavy duty cooling(K5L) package and the Z82 trailering package.  From what I see online the K5L trucks have larger oil cooler lines than a standard truck.  A couple guys that did write ups on repairing the lines had 3/8" the same as the trans cooler lines.  The oil cooler lines on my truck are visibly larger in diameter than the trans cooler lines.  I just repaired one of the trans lines today by cutting the factory crimp connectors off and replacing them rubber hose with new hose and pinch clamped it to the steel lines.  The 3/8" I.D. hose was loose fitting on the factory barbed fittings so I'm hoping the 3/8 hose will fit but maybe a little snug on the oil cooler lines.  It's most likely a long shot but figured I'd ask if anyone has done this before and knows if 3/8 line fits or I need to buy the next size up?

[richard wysong]

You will need 1/2" hose, Probably will have to use hydraulic hose or a barrier hose. I hope you used power steering hose on the trans lines, Fuel line will swell up and burst. Usually the hoses are ok, just remove the crimps and double clamp the ends

[swathdiver]

If the fittings used are any indication, 3/8 for the transmission oil cooler lines and 5/8 for the engine oil cooler lines.

[newdude]

On 12/28/2024 at 5:06 PM, kyleag89 said:

As the title says I have a 2011 sierra 1500 with the heavy duty cooling(K5L) package and the Z82 trailering package.  From what I see online the K5L trucks have larger oil cooler lines than a standard truck.  A couple guys that did write ups on repairing the lines had 3/8" the same as the trans cooler lines.  The oil cooler lines on my truck are visibly larger in diameter than the trans cooler lines.  I just repaired one of the trans lines today by cutting the factory crimp connectors off and replacing them rubber hose with new hose and pinch clamped it to the steel lines.  The 3/8" I.D. hose was loose fitting on the factory barbed fittings so I'm hoping the 3/8 hose will fit but maybe a little snug on the oil cooler lines.  It's most likely a long shot but figured I'd ask if anyone has done this before and knows if 3/8 line fits or I need to buy the next size up?

 

 

2007-2013 1500s there's only one set of engine oil cooler lines listed for these with a V8.  There isn't two different sizes either.  84828848 is the engine oil cooler lines, bigger than 3/8", probably closer to 5/8".

 

Trucks without heavy cooling K5L don't have engine oil cooler lines RPO code KC4, just transmission cooling but without the aux cooler.  

 

K5L adds the transmission aux cooler and the third line to complete that circuit, and adds the KC4 engine oil cooler lines.  

 

 

 

Edited January 4, 2025 by newdude

[kyleag89]

Thanks for the info, it's been awhile since I've been on the forums.  I got the job done and 3/8" ID hose fit on both the oil cooler lines and the trans cooler lines.  The trans lines were a bit smaller but it still worked.  The 3/8" line was a perfect fit for the oil lines.  I used pinch clamps like the type used for PEX tubing in plumbing so they pinched the hose perfectly.  Been about 2 months now and no more leaks!