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Deleted the EGR in my LML. Was told now I have to run a vacuum on my coolant system.

9K views 12 replies 3 participants last post by  Headd1976 
#1 ·
I deleted the EGR and replaced the factory up pipe on my 2014 2500HD LML. I did all the work myself and yes it was a pain in the ass! Took me 2 full days! But I got everything back together and it all seems to be working fine. I refilled the coolant per the instructions in the duramax supplement book. But today I went by my local mechanic and to talk to him about what I did and he asked me if I ran a vacuum on the coolant system to remove the air?? Well of course I didn't because I don't have that tool and he told me that because I didn't do this I could cause major problems with my engine specifically a blown head gasket. And that I also probably ruined the two brand new thermostats that I just installed. He said the t-stats will go into a "fail safe" position and stick open when the is air trapped in the lines and the coolant gets too hot. So for $250 plus parts (new t-stat, more coolant) he could run the vacuum on the system and replace the thermostats and hopefully no damage was already done. My issue is that I haven't read in ANY of the EGR delete instructions or in any threads that you have to run a vacuum on the coolant system. I know its a faster way to get the air out instead of running it with the cap off and adding as needed, but is it something that HAS to be done to avoid damaging my engine?? Any help will be much appreciated. Thanks, Wes

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#2 ·
Im no expert but this sounds like a load of crap. Seems like this shop is trying to take your money. I changed my thermostats myself a year ago and did not put a vacuum on my system. Everything is still just fine on my truck. In fact, I didnt even bleed the system properly. I had to heat cycle it a few times to get all of the air out. (Heat cycle is drive till it gets up to temp then shut it off till it cools down then repeat)

I have pulled my 9000lb Travel trailer over 2700 miles since the T stat change with no issues.
 
#3 ·
Yea it just didn't sound right to me that you would have to run a vacuum on the system since all of the instructions/posts about the egr delete never mention having to do this. I spent two hours looking through the Internet and I couldn't find ONE thing about having to vacuum the system. What bothers me is that this mechanic had worked on my truck several times in the past and our kids even play sports together, I just wouldn't expect him to try and make me do something just to make more money. And if I did wreck my engine over a couple hundred dollars I would be beyond devastated.
 
#5 ·
I don't know why you can't read it when I attach it to this post but it is a picture of his computer screen at the dealership service dept showing what the steps GM tell them to do when refilling the coolant system. It is very close to the same instructions in the duramax supplement. Run the truck at 2500 rpm with the cap off for 5 min, let it idle for 5 min and add coolant as needed to keep the level at the seam of the tank, repeat one more time, then top the tank off and put the cap back on (short version).
 
#6 ·
Sounds like your mechanic is a 'buddy-f@¢ker' :woopass
 
#8 ·
I just left another diesel mechanic shop in my area and I think I just found my new mechanic. He agreed that you DID NOT need to run a vacuum on that cooling ssystem and that if it's not overheating and it's holding coolant than its good to go. The only reason he would use the vacuum would be to speed the bleeding process up, instead of having to run it add some, run it add some. But he said he has never had a problem with the duramax getting air trapped in it, he said even if you didn't follow the procedure that they tell you to it would still probably be ok because it would purge itself out (this is why the t-stat has two bleed holes)
 
#10 ·
Well I thought I had the problem solved but I just drove to Lumberton and back (approx. 80 miles) and my low coolant light came on again. Popped the hood and found that it has been spewing out of the overflow side, I had coolant all over the passenger fender well. And the overflow side is completely full and the otherside empty???
 
#12 ·
Never got hot and I checked all of the hoses I could get to easily and could not find any leaks. Does anyone know how these caps are supposed to work? Is it possible that the cap is not releasing the pressure out of the tank causing it to push coolant out of the overflow? Or am I being too optimistic to think I could fix this problem with just screwing on a new cap? Lol
 
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