How to do a Leak Back Test on Chrysler Voyager 2.5 CRD

How do you do a leak back test on a Chrysler Voyager 2.5 CRD (Common Rail Diesel) engine. This works on others as well. No need to buy the expensive leak back test tool.

Most CRD engines in this league have about the same allowed back flow rate at about 25ml per minute at idle max.

Here is what you need to make a leak back test kit on the cheap.

A 3/8 inch see through plastic hose about a yard long

see through hose
Plastic hose
at least a 25 ml syringe







A Syringe that holds at least 25ml of water and a magic marker. Plug in one end of the hose and fill it with 25ml of water from your syringe. Mark the hose with your magic marker (also called permanent marker) where the 25ml is.

Leak back nipple CRD engineTake the plug out and let the water out. Now go to your car and take the leak back hose off of the injector. It’ll be on the top and there is a little springy thing you need to remove with a needle nose plier or by hand before you pull the hose off in an upword motion. Might be a bit resistant but you just pull it up and it’ll pop out. (don’t breake it)

Plug the end of that hose you just pulled off with a twig or something so it’s airtight or else fuel will come out of it.

Push the end of the 3/8 inch see through hose (make sure the 25ml marked end is going onto it) to where you pulled the leak back hose off of and hang the other end up to the hood or hold it in your hand.

Start the engine and let it idle and count to 1 minute and than turn the engine off and see how much fuel leaked back.

If it’s more than 25 mill the injector is no good, if it’s less, the injector is good. Do this with all four (or whatever number of injectors you have) injectors.

Now you can loan your test kit to a friend or sell it on Ebay if you don’t need it any more.

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