Coolant Refill Help Needed Please


GTHunter

GT Owner
Feb 14, 2012
103
Houston, TX
gentlemen:

Decided that it was time to change coolant in the GT. Following the service manual I have drained both the radiator and the supercharger cooler at the front of the car via the petcocks. After tighting the petcocks I installed the Airlift tool(similar to RADkitplus) on the degas bottle and proceeded to attempt to create the required vacuum to pull coolant which is approximately 24lbs. I have attempted this on both bottles and have not been able to create more than about 10 lbs vacuum on either. It will hold these pressure amounts over time and I witnessed no cooling issues with the car prior. 10 lbs is not enough vacuum to draw the full coolant amount needed to replenish that which was withdrawn. Hopefully one of you has some ideas of what I am missing here. thanks for any ideas. GTHunter
 

Art138

GT Owner
Mark II Lifetime
Jan 4, 2011
328
Weston,FL
I had the rear of the car lifted (on race ramps) before I drained the coolant from both radiators. For the airlift tool to work properly you need 26LBS of vacuum; your compressor needs 120-130 PSI to pull vacuum consistently. I left it on for over one hour. Are any of your hoses collapsing?
 

GTHunter

GT Owner
Feb 14, 2012
103
Houston, TX
How much coolant did you get out? I may just try to use a larger compressor.
 

Art138

GT Owner
Mark II Lifetime
Jan 4, 2011
328
Weston,FL
All but about one gallon, believe you need to pull bottom engine plugs for the rest. NOTA4RE advised that they are able to drain all by just using/pulling vacuum. He is a vendor on this forum you might send him a PM.
 

FENZO

GT Owner
Mark II Lifetime
Jul 7, 2008
1,516
Lafayette, CO
I think you are on the right track looking at a larger compressor. The Venturi vacuum action is a function of, among other things, psi and cfm. I'd guesstimate 4 cfm would be min required at 90 psi. The more the better of course.

What is your compressor rated scfm @ 90 psi?
 

nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
3,559
Just literally finished doing a GT less than an hour ago. I agree with others - maybe your compressor is too small. I keep the shop air regulated at 125psi and it has no problem to pull -25 on the RadKitPlus which pulls all of the hoses flat. PM me if I can be of any help...
 

BlackICE

GT Owner
Nov 2, 2005
1,412
SF Bay Area in California
I'm using a compressor that puts out about 8+ cfm at 90 and it works fine.
 

GTHunter

GT Owner
Feb 14, 2012
103
Houston, TX
Shadowman walked me through several checks on the system yesterday. We believe the little compressor just is not getting us there. Will get back on it next weekend with larger flow compressor. Thanks to all for suggestions and again thanks to Shadowman for his time and guidance…very much appreciated!
 

KJRGT

GT Owner
Mark II Lifetime
May 4, 2006
2,838
SoCal
Good luck GT Hunter. Keep us posted.
 

GTHunter

GT Owner
Feb 14, 2012
103
Houston, TX
Back on the GT today and tested the air compressor theory ... no difference. A quick consult with Shadowman suggested either system leak or problem with tool. Since both degaus bottles could only pull to about 10 psi I leaned towards the Airlift tool. A quick walk over to a neighbor(Snap On Rep) in my garage complex and I was the owner of the RADKITPLUS and hoping that would do the trick. Off with the Airlift and on with The RADKIT and presto I am at 28 lbs. in seconds. We shut the doors today with great relief and both cooling systems full with fresh fluids. I have to extend my thanks again to Bill aka Shadowman for his guidance and patience with my phone calls. THANK YOU! Please note the Airlift tool was brand new and obviously a lemon as it appears everyone else here has had good luck with that brand. The RADKITPLUS was certainly more expensive, but after two weeks of frustration worth every penny. Thanks for all the help.
 

viva gt

GT Owner
Sep 15, 2010
404
toronto canada
What a great feeling to find that it was just a tool issue.
 
Aug 25, 2006
4,436
You did a great job of remaining relaxed and focused as we walked through the troubleshooting processes.

It was my pleasure to be included in your project.

Thank you and takes care.

Shadowman
 

fordgt6

GT Owner
Mar 19, 2009
66
East Lake Weir, FL
Can the Radkitplus be used to remove the old coolant? Thanks.
 

Waldo

GT Owner
Mark IV Lifetime
Sep 7, 2005
755
Fort Worth, TX
Can the Radkitplus be used to remove the old coolant? Thanks.
I've changed the coolant on my GT four times, and I am not aware of a way in which the Radkitplus can be used to remove the coolant. I have only used it to remove the air from the systems before I refill them.

To drain both cooling systems, I open the radiator and intercooler drains at the front of the vehicle and then remove the two threaded plugs in the engine block. The front splitter and both pans under the engine will need to be removed to gain access to those drain points.
 

Tomcat

GT Owner
May 23, 2013
832
North Carolina & Perdido Key
speed is life...KEEP YOUR KNOTS UP!