JoeCB

I have just turned 100,000 mi on my 05' Uplander... time to change the coolant! Are there any special procedures to ensure a complete fill and all air is bled off? This engine uses the "pink stuff", right?

Thanks

Joe

cams 98 silverado

just drain and fill and run the thing with radiator cap off and let it burp the bubbles.easy. its easy if you know where the drain plug is. look on drivers or passengers side of radiator at bottom. and after drain, run some of the radiator fluch chemical found at local auto parts place and read the instructions on there. what i did was drained it, put a hose to my radiator with drain plug out, poured water in til it was crystal clear, then plugged it, turned motor on, put rad flush chemical in it then put hose in radiator an ran it til it was filled. make sure your heater is on full hot and at least turned to low fan. it opens the heater core and flushes that as well. what i did was run it for 5 minutes, drained it with motor on, filled it and drained it some more then put the plug in again, filled with fluid then let it burp the bubbles. its easier to do a flush if the motor isnt at running temp. because i work at jiffy lube and it makes flushing rads fun when you got a hot radiator and put cold coolant in and the reactions are bubbles and steam.

Todd Mann

i have a uplander van and it does not have and heat till you get to 2000 RPM. i dont know why i have flush the eng. and i still have no heat till get 2000. help if you know

EinST

Welcome to the forum. It's hard to look up anything without the year and trim level of your Uplander. How did you "flush the eng." and did it involve back-flushing the heater core? If not, unplug the two heater hoses that go to the heater core and then try running water through the heater core in one direction and then in the other direction.

stpiean

good luck. I have had same problem for 3 years, dealer did everything possible, now they don't even try to fix it. says GM rep says it is a design flaw.

they are aware of the problem, that is why they are now obsolete. Core sits to high in the firewall molding. so air locks.

So are we suppose to pay 30grand for van and go merely on our way

stpiean@hotmail.com

I am looking at suing them. This is not acceptable. do you think it is?

tech2

to some extent these designs do produce more heat at higher rpms due to more coolant flow produced by the waterpump at higher rpms. The problem is more evident when air is trapped in the system. todd mann symptoms can also be caused from low coolant levels.

I have dealt with this concern many times. 95% of the time a drain and vacuum fill of the cooling system corrects the problem. the system must be vacuum filled or air pockets will remain in the system that will not be bled out with thermo-cycling.

The system must be partially drained for the vacuum fill to work properly. It will not pull air out of a filled system.

on stubborn systems quickly removing and reconnecting the heater core line while the engine is running will burp the system.

I heard of some techs installing a restriction into the system to keep coolant in the heater core longer. I have never had a reason to perform this step to resolve this issue.