Issues with the Cooling System

ifeellethal · January 22, 2022

Hi Guys,

I recently bought an 08 GX470 and joined the forum, glad to be apart of the community now! As the title says, I'm having issues with changing out my coolant in my GX. As far as I know, the GX470 takes 3.4 gallons of coolant; that's the capacity in the manual. I cannot add anywhere close to that amount. I imagine I've added around a gallonish or so. I've followed all the popular videos on YouTube... ChrisFix, Engineering Explained, GX*BOB, and others but no luck. That's the short version, below is the full story. I'd really appreciate some help with this.

As stated above, I recently bought a used 08 GX470 with 202,000 miles on it. I found one with a decent history and it seemed all right. There was no record on the timing belt and water pump. I took it to a Lexus dealer to have it inspected. They came to the conclusion the timing belt and water pump should be replaced along with some other parts. Moving along, both parts were replaced by one of the dealer's mechanics on the side. I drove the vehicle before buying it and after I got it I drove it on the highway for a while. I never had any issues, check engine lights, or signs of overheating.

After buying a new car, it's good to put new fluids in and flush whatever you can out, peace of mind. Now, here's where things get confusing for me. I've never drained a radiator or flushed a cooling system, and I'm just following what I see online. I drain the coolant out of the radiator and about 1-2 gallons come out, 2 is generous. I flush the system out with distilled water, get that leftover stuff out. I then fill up the radiator as much as I can before starting the engine; I put in close to a gallon. From what I saw, you should be able to add more coolant in once the engine starts. I wasn't able to add much.

I've let the car run numerous times now. I've drained coolant out and refilled again, bled the air out, nothing different. I was only able to add like a gallon or so to a system that says it takes 3.4 gallons. Whatever I'm hearing online doesn't apply to my situation and it's really confusing. I did some research and thought maybe the thermostat wasn't functioning properly so I replaced it. I ran the car a couple hours ago and nothing different happened other than the electric cooling fan turning on for the first time. I had my funnel on there with coolant in it to get some in there if it would go down, no luck. No overheating while idling, no check engine lights, car gets to operating temperature just fine, heat in the cabin. I'm thinking about driving it soon to see if it's fine and I'm overthinking.

What do you all think?

Edited January 22, 2022 by ifeellethal

sha4000 · January 22, 2022

15 hours ago, ifeellethal said:

Hi Guys,

I recently bought an 08 GX470 and joined the forum, glad to be apart of the community now! As the title says, I'm having issues with changing out my coolant in my GX. As far as I know, the GX470 takes 3.4 gallons of coolant; that's the capacity in the manual. I cannot add anywhere close to that amount. I imagine I've added around a gallonish or so. I've followed all the popular videos on YouTube... ChrisFix, Engineering Explained, GX*BOB, and others but no luck. That's the short version, below is the full story. I'd really appreciate some help with this.

As stated above, I recently bought a used 08 GX470 with 202,000 miles on it. I found one with a decent history and it seemed all right. There was no record on the timing belt and water pump. I took it to a Lexus dealer to have it inspected. They came to the conclusion the timing belt and water pump should be replaced along with some other parts. Moving along, both parts were replaced by one of the dealer's mechanics on the side. I drove the vehicle before buying it and after I got it I drove it on the highway for a while. I never had any issues, check engine lights, or signs of overheating.

After buying a new car, it's good to put new fluids in and flush whatever you can out, peace of mind. Now, here's where things get confusing for me. I've never drained a radiator or flushed a cooling system, and I'm just following what I see online. I drain the coolant out of the radiator and about 1-2 gallons come out, 2 is generous. I flush the system out with distilled water, get that leftover stuff out. I then fill up the radiator as much as I can before starting the engine; I put in close to a gallon. From what I saw, you should be able to add more coolant in once the engine starts. I wasn't able to add much.

I've let the car run numerous times now. I've drained coolant out and refilled again, bled the air out, nothing different. I was only able to add like a gallon or so to a system that says it takes 3.4 gallons. Whatever I'm hearing online doesn't apply to my situation and it's really confusing. I did some research and thought maybe the thermostat wasn't functioning properly so I replaced it. I ran the car a couple hours ago and nothing different happened other than the electric cooling fan turning on for the first time. I had my funnel on there with coolant in it to get some in there if it would go down, no luck. No overheating while idling, no check engine lights, car gets to operating temperature just fine, heat in the cabin. I'm thinking about driving it soon to see if it's fine and I'm overthinking.

What do you all think?

You still have lots of old coolant in the engine block. In order to get it all out you will need to remove the engine drain plugs.

https://www.clublexus.com/forums/gx-2nd-gen-2010-present/884009-coolant-flush-fluids-questions-comments.html

ifeellethal · January 23, 2022

8 hours ago, sha4000 said:

You still have lots of old coolant in the engine block. In order to get it all out you will need to remove the engine drain plugs.

https://www.clublexus.com/forums/gx-2nd-gen-2010-present/884009-coolant-flush-fluids-questions-comments.html

Thanks! I had asked this question on another forum and I was directed to that link as well. I think I will drain the radiator again and do the block as well. Add the coolant back and even replace the radiator cap, it was recommended. I remembered when I pulled the cap for the first time a gasket or something came off. Cheers!