2004 Suburban Coolant Service

Hi. First post here...

I've searched the forums for "coolant hose replace" under suburban and found nothing that will answer this question, so if I missed something, please be kind. :smooch:

Question: Vehicle is 2004 Suburban Z71 4WD with 5.3 Flex Fuel engine with the auto climate, seperate front left/right and rear aux controls. about 90K miles. I wish to perform a coolant service, to replace the hoses and thermostat. I know I use DexCool as the coolant.

How many hoses are there, what locations? I'm aware of the upper and lower main radiator hoses, but I figure there are more. Should every hose be replaced?

From a view on RockAuto, it appears that there is a call for 5/16 (throttle body hose?), 1/2", 5/8", and 3/4". Do I need to go to a dealer for molded hoses, or can I just pick up a roll of each hose diameter and R&R? What is best for this situation?

Also, (please forgive me, but I haven't actually done much underhood investigation, given the extreme rain and lack of daylight), but I have one of those vacuum coolant system service kits that allows me to pull a vacuum and then refill the system... I'm not sure if there's an aux heater core, and if that heater core is at a higher elevation (in a level vehicle) than the overflow tank or filler cap. Are there hoses in the interior of the vehicle?

Mechanically, I'm reasonably skilled, but I haven't worked on this vehicle beyond oil changes and 1 o2 sensor since I bought it new in 04. It is time for some preventive maintenance.

Any help or hints, suggestions would be greatly appreciated.

Thank you all in advance. :)

-junkrider.

So, I completed the service.

To answer my own questions, it was simply upper and lower hoses, a 30 inch 5/8" hose from the cores to the block, and a split hose from the cores to block with an extension to the overflow tank.

There is no radiator neck. There also is no drain plug. Remove the lower hose and drain it.

cut the old heater hose, run a flush from garden hose through it. After flushing for about 10 minutes the water ran clean out the top of the overflow tank.

The hoses were $35 for the split core hose from Advance, and $35 for the radiator hoses combined from Autozone, and about $5 for the 5/8 heater hose.

Swapping the hoses was easy. The split hose has a slide on, clicky fitting that is easy to release by pushing the hose to the connector, and squeezing the flexible plastic release by hand, then pulling off.

There is a thick plastic band to clamp the hose at the core at one end of the heater hose, holding the quick disconnect to the core. I hack-sawed the plastic band clamp to remove it. This allowed me to re-use the quick connect on the new hose, since the new hose lacked this physical interface.

I installed the new hoses, and then used the Airlift 550000 to refill the coolant. All heat worked beautifully immediately.

I highly recommend the airlift tool, as I've done several annoyingly tricky coolant changes in the past, and this one went REALLY well for my first time using the tool and servicing a dual heater core system. It took about 5-10 minutes to refill the coolant system, and I didn't have to f with it.

Hope this helps someone....

Now, can anyone help me with my other post about the tire monitor system and airbag light?

I can't find your orther two posts about the air bag and tire system? Maybe it's just me? Can you post a link to them?

the tool you used to purge the air from you engine coolant system is good, but not necessary. with a drain of the system and as you found the removal of the radiator hose lower is required. what will occur is you will only remove about 2 gallons of coolant this is also with purging out the heatercore traped coolant.

NOW YOU HAVE STILL TRAPED IN THE ENGINE 2 GALLONS OF COOLANT.

ON EACH SIDE OF THE BLOCK IS A DRAIN PLUG. this is impossible to remove I have found and dealer techs told me not to mess with it. I failed to lossen these plugs. need a 7/8 allen socket to try. this is where the block heater would go if equipt.

hopefully with your flushing out the system you installed at least two gallons of dexcool GM approved coolant. I use 2.5 gallons . that is about 65% dexcool .