|
I have a friend who is a technician at the GM proving grounds in Milford (GMs R&D center) and I called him to ask. He says he has changed hundreds of pumps over the years of DI testing.
He says the purple / blue stuff on the threads is just a whiteness die. It’s to show the fitting was installed and tightened correctly for warranty / insurance reasons.
Now he says that they have re-used lines multiple times with no issues. Says the trick is to initially finger tighten slowly and to get the original “dimple” that was made upon the original torquing to seat in the seal. If they aren’t lined up exactly the same, it will create a new “dimple” and it will cross at two points with the original dimple, and will leak where the two cross.
He says they have probably a higher than 90% success rate with reusing the lines, and they have test mules (trucks for running around the area) that have had multiple pumps over the years with the same lines, but as he stated, nobody really knows the long term effects. Will the connection stay sealed as good as a new one for 200,000 miles? They dont know.
Just like us, they are trying to save the money too. Like he said, if they used a new line for every pump swap they would have added millions of dollars in parts and downtime.
I will more than likely give it a shot with reusing the lines.
|