Duramax LML Coolant Bypass Kit 2011-2016 Duramax Diesel 6.6L
This John C Garage coolant bypass kit is the ultimate combination to prevent any leaks or headaches down the road on your off-road 2011-2016 Duramax LML. We pride ourselves on having this kit in stock and ready to ship at all times! We have commonly asked questions at the bottom to help answer anything you're unsure of.
It’s very common that we see the black or blue coolant hoses from other solution kits come apart at the crimped ends or the hose ripping apart leaving you with a huge coolant leak and usually stranded. Take a look at the 2nd photo for example of these cheaply made hoses that this kit replaces entirely. Everything needed to replace those lines is included! If you have experienced a leak with yours, here is your fix. This kit offers a more robust coolant routing with no sacrifices to the coolant system at all.
You will need to remove the down pipe to gain access to the coolant plug on the rear of the engine (5th photo) so we highly suggest replacing it with a full 3" down pipe if you do not have an aftermarket down pipe already. The 3" down pipe fits much better than the factory down pipe making it easier to install. The down pipe we offer in the drop down option can be viewed here by itself. It is from Wehrli Custom Fab and is the stainless steel version. Click here
**Down pipe selection!** For the 2015 LML Duramax, be sure to physically look at which downpipe you need! It could be either the vband (11-15) or if it has 3 bolts at the connection, it's (2015-2016). If unsure, send us a picture and we'll be able to tell which you need!
Here is the upgraded coolant block off plate we suggest doing at the same time as the coolant bypass kit which can also be viewed on the last photo of this listing. Click here
LML Coolant bypass hose
Duramax LML coolant hoses
LML leaking coolant
Duramax LML coolant hose fix
Commonly asked questions:
Q. Will this affect the coolant system or heat in any kind of way?
A. Not at all. This system works exactly like your coolant system did from factory. No sacrifices made and will function exactly the way it does now.
Q. I need this kit badly, do you have it in stock?
A. In the 5 years we have been selling this kit, we have never ran out of stock and keep several hundred kits on hand at all times!
Q. I need to expedite this kit because my current line are leaking, can I do that?
A. During the checkout process, there are multiple options through UPS to expedite this kit within the lower 48 U.S. Select the shipping method that works best for you and we will get this kit shipped out as soon as we see the order! Keep in mind, the calcuated transit time is done in business days, so Monday through Friday.
Q. What is the optional Fleece block off plate and do I need it?
A. It is simply a nice upgrade to do when you have the coolant system completely drained. It is not needed but is nice upgrade over the factory coolant plate that uses a metal gasket and the Fleece uses a rubber oring style seal.
Q. What is included in the kit?
A. What you see in the first picture is the contents in the base coolant bypass package.
1. Coolant hose with billet fitting, two orings and clip
2. Coolant cap kit
3. Coolant block off plug for rear engine cover
Q. How long is standard USPS shipping?
A. These kits are shipped from eastern Pennsylvania. Standard ground advantage shipping is typically 3-5 business days. These transit times can vary however!
Items typically purchased with this kit.
LML Y Bridge Plate - view here
LML Down pipe plugs - view here
Passenger side up pipe - view here
9th Injector bundle kit - view here
Race version crossover tube - view here