Bocatrip

I have (as seen on recent threads) just had my radiator and thermostat replaced with a Denso aftermarket radiator and flushed and refilled with Red coolant that requires the addition of distilled water. Upon returning from Lexus and examining the job, I topped up the reservoir with approximately a half a cup (6 ounces?) of the red coolant/distilled water mixture. The reading when warm was at the full mark. I expected the next morning when the car was cold, for the level to drop back somewhat, which it did ever so slightly. I drove around most of the day and when I checked the level when the car was warm, it was lower than it was in the morning when cold. There were no visible signs of any external leaks. The temperature gauge is exactly where it was before the replacement (below the center and slightly above the 2nd line). Question.... when a radiator and thermostat are changed, as well as the old coolant flushed out and refilled, does it ever require a few top ups to get the coolant to it's proper level? I'm not sure if there may still be any air pockets that still need to purge or am I missing anything? Is there anything else I need to check? Any feedback would be greatly appreciated.

Tom57

Others have reported similar need to top off after a few trips, Boca.

Bocatrip

Thanks for the encouragement Tom. Hopefully that's all it is.

rkw77080

You did not mention operating the heater - you may have some air pocket in there...

Tom57

Air must get trapped in the lower section of the radiator, and/or in the heater core. It's summer in FL of course, but have you turned on the heat to open the heater core?

Tom57

Well, I hit submit a minute after our friend rkw ...

Bocatrip

It funny how I was thinking the exact same thing with regards to the heater core. It's been blazing hot here in Florida this past week and I wonder if the tech doing the work even bothered to put the heat on while replenishing the system. I haven't put the heat on since the install. I will check the system tomorrow when cold while removing the radiator cap when cold as well to see that the radiator is full. I'll keep the heater on for awhile and check again later. If any air pockets exist either in the heater core or elsewhere, do they dissipate on their own while topping up or must they be bled? I am not familiar with the heater water valve and am not planning on playing with it myself...

Tom57

Air in the system dissipates by bubbling up to the top of the radiator. The overflow container also supplies coolant in the event the radiator is low, but since you changed out the radiator, I would continue to check the level directly at the radiator cap after running for awhile and, of course, after the system has cooled sufficiently, even over night as you intend to do.

Bocatrip

Thank you RKW and Tom for your tremendous wealth of information. I guess what I'm getting at is this. Even if the tech was semi incompetent and did not remove the engine plugs while draining or even bleed from the heater water valve, will I still be able to get all air pockets out of the system by checking daily and adding any additional coolant that is necessary? If so, I'm fine with that. Of course, my car was originally filled by Lexus with the Pink coolant of which I requested to be removed and hopefully, they got most of it out before filling with the Toyota long life red. I guess, if you want the proper job done, you need to do it yourself, which in this case while living in Florida just isn't going to happen. Right now, I just want to get my coolant level where it should be...

rkw77080

Boca, you will not have to mess with the heater water valve directly, just set the temperature setting to as high as it will go. The A/C ECU will open the heater water valve to supply heat. The repair manual suggests for you to rev the engine up to 2500 rpm to circulate the coolant.

Tom57

And yes, all of the air will bubble up. Just check daily in the morning for a couple / few days. Opening the heater control valve (by turning temp control in the vehicle) all the way to high will allow for complete circulation of coolant which will push the air to the high end of the radiator.

Bocatrip

Great info! That's what I'll be doing tomorrow, probably one of the first and only times I have heat on while living in Florida! How long would you consider is a reasonable period of time to keep the revs at 2500 RPMs? (of course I'll be wearing my bathing suit! lol ) 10 minutes or so? I'm glad the temperature gauge is reading where it should be or I would really be flipping out. You guys are great!

rkw77080

If I were you, I'd let the engine come up to temperature before switching the heat on. That way if the A/C is blowing hot air, I can tell the heater water valve is open. I'd keep the engine rev'ed up for 3-5 minutes top.

Bocatrip

My A/C always comes out cold from the vents within seconds of turning on the car even now.

rkw77080

To open the heater water valve, you will have to turn up the temperature. Be sure to set it to the highest setting so that valve is fully open and sends hot coolant into the heater core (A/C will blow hot air).