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40 to 332 · 05-22-2017, 08:05 PM

I'm planning on completing a drain and fill of the coolant system this week. I have a 2013 in which the pressurized cap is on the reservoir tank and the second cap (non-pressurized) is located further back toward the engine. This set-up is foreign to me so I have a few questions for those of you who have changed the coolant. I understand the draining procedure as well as the emptying and filling of the reservoir tank … it's the filling of the rest of the system that is a bit confusing. The FSM wasn't especially helpful.

First, is it necessary to vacuum fill the system? There's a post indicating that without vacuum filling, you run the risk of air being trapped in the system which could cause over-heating. The post mentions the risk of a cracked head with no warning because of heat created by the trapped air (???). At the same time, there are other posts in which vacuum filling was not performed and everything turned out fine.

Second, regardless of the need for vacuum filling, I assume that the new coolant is introduced into the fill hole where the non-pressurized cap is located … correct? … and when filling you need to remove the air drain plug located near the top of the rad on the driver's side to allow air to escape while filling. Is this right?

Third, you add coolant up to the neck of the fill hole, and then turn the car on, allow things to heat up, and let the coolant cycle a couple of times. You then add coolant as needed to continue to bring it up to the neck of the fill hole. Then turn the car off and re-cap the fill hole. Then monitor the level of the coolant in the reservoir tank over the course of the next few days, and add as needed.

I've changed the coolant before on a number of different vehicles without issue. However, this system is a bit different and I just want to ensure that I have a good understanding of how to do things right. Thanks for your input!

05-22-2017, 08:05 PM	#1 (permalink)
40 to 332 Enthusiast Member Join Date: Apr 2013 Location: Kimberley, BC, CANADA Posts: 447 Drives: 13 370Z BS M6 Sport Rep Power: 439	Coolant Change Questions I'm planning on completing a drain and fill of the coolant system this week. I have a 2013 in which the pressurized cap is on the reservoir tank and the second cap (non-pressurized) is located further back toward the engine. This set-up is foreign to me so I have a few questions for those of you who have changed the coolant. I understand the draining procedure as well as the emptying and filling of the reservoir tank … it's the filling of the rest of the system that is a bit confusing. The FSM wasn't especially helpful. First, is it necessary to vacuum fill the system? There's a post indicating that without vacuum filling, you run the risk of air being trapped in the system which could cause over-heating. The post mentions the risk of a cracked head with no warning because of heat created by the trapped air (???). At the same time, there are other posts in which vacuum filling was not performed and everything turned out fine. Second, regardless of the need for vacuum filling, I assume that the new coolant is introduced into the fill hole where the non-pressurized cap is located … correct? … and when filling you need to remove the air drain plug located near the top of the rad on the driver's side to allow air to escape while filling. Is this right? Third, you add coolant up to the neck of the fill hole, and then turn the car on, allow things to heat up, and let the coolant cycle a couple of times. You then add coolant as needed to continue to bring it up to the neck of the fill hole. Then turn the car off and re-cap the fill hole. Then monitor the level of the coolant in the reservoir tank over the course of the next few days, and add as needed. I've changed the coolant before on a number of different vehicles without issue. However, this system is a bit different and I just want to ensure that I have a good understanding of how to do things right. Thanks for your input!