Service manual procedure for coolant drain and fill

[NC Yukon]

2004 YukonDenali with 6.0L Vortec 6000 engine. 228k miles.

I want to do a coolant drain-and-fill (not any sort of power flush), but I'm seeing lot of differing advice on youtube on how to refill the system and how to bleed/burp/purge air within the cooling system.

I'm looking for the procedure recommended by the official service manual. I figured this would already be discussed in the forum archives, but I don't see it.

I was surprised to learn that there's no cap on the actual radiator on a 2004 Yukon.

Does anybody have the official procedure for refilling and purging?

Thanks.

 

[drdave81]

Pull the lower hose, unless you have a drain on the radiator. Put it back on once it's drained. Refill the system through the overflow and then run the vehicle until it reaches operating temp and the thermostat opens. Drive it for a bit and recheck coolant level to make sure it's topped off. Simple and easy.

 

[NC Yukon]

Well, that's a lot simpler than removing the upper hose at both ends for filling as one youtuber recommended!

Thanks for the info!

 

[drdave81]

You only need to remove the lower hose from the radiator, just leave it on the water pump. No need to remove the upper hose. YouTubers can be such idiots. Check to see if your radiator has a drain on the driver side at the bottom. It'll be a little piece sticking out you can twist loose and drain that way as well, so you don't even have to mess with the lower hose clamp.

 

[OR VietVet]

Drain with the lower radiator hose off at the radiator. When you refill it, allow for a very slow pour and jack up the passenger side of the vehicle at the frame behind the front tire. Run it periodically for about 1 minute, after you get to the point of it not allowing any more coolant. Leave the reservoir cap off unless it starts to push the coolant out. Keep topping off and run longer with cap on and watch the reservoir tank and monitor the upper radiator hose for hot when the thermostat opens. watch the temp gauge too. When you are confident that the system is full, remove some coolant from the bottle to the full level. Test drive and monitor. I have used this method on a few GMT800's with no problems. When the system is empty, change the thermostat.

 

[NC Yukon]

Interesting idea on jacking the passenger side. The resevoir tank is already the high point in the system. Is your thought that the slightly increased head pressure will more effectively purge air pockets?

 

[SpareParts]

I would think to do a good drain and fill, you would need to take off the lower radiator hose. Remove the drain plugs on each side of the block. If you have rear heat, then un hook that at the lowest point.
Should get most of the old coolant out

 

[Marky Dissod]

Interesting idea on jacking the passenger side. The reservoir tank is already the high point in the system.
Is your thought that the slightly increased head pressure will more effectively purge air pockets?

It's to raise other points to make burping the air out easier.
Still doesn't hurt to pour SLOWLY. One way or another, you gotta be sure to get ALL the air out.

 

[Fless]

See the link below, and navigate to your specific vehicle info using the links at the top of your browser window.

https://charm.li/GMC/2004/Yukon%2FDenali%202WD%20V8-6.0L%20VIN%20U/Repair%20and%20Diagnosis/

 

[Fless]

I will add that if you don't fully drain the coolant using the block plugs, there will be coolant left in the engine. At a minimum do a garden hose flush or similar, using fresh water. Fill and run the engine to dilute the remaining coolant, then drain. Some people repeat this until clear water is being drained.

There will be some water left in the block, so calculate how much full-strength [Dexcool] coolant to add to get to your desired mixture (e.g., 50/50, 60/40) and add that first. Fill the remainder with distilled water to minimize mineral deposits.

 

[OR VietVet]

Interesting idea on jacking the passenger side. The resevoir tank is already the high point in the system. Is your thought that the slightly increased head pressure will more effectively purge air pockets?

All I can say is that the procedure always works and I trust the tech that shared it with me. I know him and completely trust his input and therefore have never asked a bunch of questions. I have to remember, that at my age, the more info I take in, the more that I lose on the other side of my brain.

If you are changing coolant and have not gone WAY too far with the old coolant, the old coolant left in there after draining at lower radiator hose, is minimal. Like @Fless said, can even do a garden hose flush and still would be minimal left in the system. Take the old thermostat out, flush it and install new thermostat.

 

[Coveman]

I don’t know why I waited on getting a fluid extractor pump, but once I did it made messy jobs like this a breeze! Sumpin like this: HTZSSON 9.5 L/2.5 Gallon Oil Extractor Pump Pneumatic/Manual, Fluid Extractor Oil Change Pump Extractor with 5 Tubes and A Brake Bleeding Hose for Automotive, Boats https://a.co/d/4ZX4gXy