Cody or Kcarsen, not sure if who had the fix, but I I just started having this headache too. What is the proper steps to bleeding the coolant system to cut down on the heater core air lock? Thanks.

 

Ya I had the same issue with my up lander is a 2008 that I purchased this last March and it is now your later in my Van stopped today my engine light came on set to change my oil which I just did not too long ago and my reduced engine power light came on and my heat my temperature Gauge was all the way to the Max I pulled over I put some cooling in the vehicle and drove less than a mile home and it was already back heated to the Max and him it does not blow any air when your idol it is not stable at all as as serviceability Stir I had nothing but problems and headaches with his Van in him desperate because of smiling vehicle to get my children around and very important doctor's appointments and stuff being in the middle of a pandemic in having this vehicle we've played replaced so much stuff on it the upper a arms Actor alarms whatever will hubs and we replace the so many different things I can even mention multi I would have to get out my stuff but airlines like you to contact me please thank you

 

sounds like you lost your coolant. probably blew a hose. repair / refill.
the electronics nearly prevent you from totally destroying the motor,... so thats a plus

 

We have an 08 Uplander with the same issue.
Coolant is fine, water pump is fine etc. When at idle it gets cold and when pulling away it warms up.
If I were to guess it almost seems like a flap in the air duct requires forward motion to direct heat. I have also noticed driving in reverse doesn't heat up either. I was trying to find a diagram of the heat ducting system to see if I can make sense of this issue. We live in Northern Ontario Canada so yes it can get cold.

 

I sure would like to be able to speak to you oin the telephone about rerouting my heater hose. All the information I have been able to read still leaves me a tad bit confused and that confusion is preventing me from attempting the fix.

The bypass in this picture indicates the new hose goes from the water pump and sweeps around the engine, but to exactly where? To the three way junction fitting, or does it go all the way to the firewall and go on the inlet/outlet metal pipe coming directly from the front heater core?



The picture unfortunately cuts off the view.

If it goes directly to the inlet/outlet I am wondering what happens to the flow when you cut out the three way junction?

I assume you are stopping the flow getting to the rear heater core if you bypass the three way junction fitting and connect it to the pipe that comes out of the front heater core at the firewall?

If only the picture was as clear about where as the one showing the other end of the bypass connection to the water pump like in this picture.



Now I see you are mentioning something about a new 3/4 inch pipe. That hit me out of the blue. Pipe, or hose? Also my van uses a 5/8 hose.
I guess you could use either as they are pretty close in size, but still you said pipe and not hose, so more confusion.

In case you are wondering what I am talking about when I mention the three way junction fitting here is the picture of it.

There are two of them. One for outlet and another for the inlet.

Both of them are located just below where the first picture in this post cuts off your view. Also both are connected from the two hoses coming directly
from the inlet/outlet heater core pipes at the firewall. Then one directs the flow to the water pump while the other I guess goes to the auxiliary heater core
located in the rear of the van.

 

What you are describing has been determined to be caused by the heater core being mounted in a less than favorable position. The best fix is to reroute one of the heater hoses, or both hoses. (see pictures in above post)
It seems the water pump is not strong enough to keep the coolant flowing at idle. By removing the unnecessary twists. turns, climbs, and dips it makes it easier for the water pump to maintain
a constant flow even at idle. I will say that flushing the heater core and by extension the whole system using a garden hose made enough difference in my 2008 van to make a significant improvement
not only in terms of more heat, but also in reducing the amount of rpms necessary to get the heat going, but I still need to do the bypass. After my flush my van would get heat at 1500 rpms instead of 2000+ rpms.
That change alone gets the van heated much quicker and keeps it heated well enough to at least allow me to drive in the cold. I Door Dash, so its very important for me.

Check out my other post I just made where I asked for clarification on rerouting the hoses. You should be able to get the picture on things much better after that.

Truth be told its a manufacturing defect, but GM went into bankruptcy before it ever got acknowledged. In fact the bankruptcy was also the reason the Uplander was discontinued
due to the government terms they drastically reduce the number of models they manufactured.

What was even more concerning was why the bankruptcy? It was in my opinion caused in large part by GM's decision to switch coolants to DEX-COOL. The lawsuits were endemic and the number of recalls they
would have had to make good on was impossible for them to take care. Their first formulation of DEX-COOL caused every vehicle that used it any gaskets that came in contact with it to eventually fail.
It was a chemicals incompatibility issue with the predominantly used gasket material at the time. The testing labs missed it when they gave GM the go ahead to sell it.
It would have been an impossible recall; never mind the lawsuits from third party consumers who decided to make the switch to Dex-Cool. The first lawsuit resulted in a settlement with GM,
but as the issue gained momentum it became obvious it would become overwhelming. It took time for the Dex-Cool problem to show up, but would eventually take down every vehicle that
was using it, or had used it..

On the upside the automobile mechanic industry went onto having plenty of business for years from the countless as well as clueless vehicle owners with the sudden epidemic of head gasket repairs that most people never even thought
were connected to, or associated with the DEX-Cool. That repair alone involving removing the heads to install new gaskets would have been bad enough, but other gaskets in other parts of the vehicles were affected as well.

There is a Youtube video that explains the history of DEX-Cool. In a way you really can't blame GM after watching it, but in the end they had to be the responsible entity to legally remain on the hook for the mistake. The laboratories gave Dex-Cool the go ahead
having given it every conceivable test in their arsenal, but their tests simply could not take into account, or project the real world conditions years down the road outside of their labs until it was far too late.By then Dex-Cool had saturated the market as this great
new innovation. In truth it was. Just not in the first formulation as anyone today can attest the rest of the auto makers moved to their own versions (colors) of Dex-Cool copy cats.
It is after all a far superior coolant solution by far than we used to have. Just remember a whole heck of a lot of people paid for it in car repair bills.
P.S. The new formulation sold today will not cause the same problem.

 

It would be wonderful if you could help alleviate some of the confusion on how to reroute these heater hoses. Read the above posts to see what I mean.

In a way you already have. I can see the hose connected at the T Connector near the water pump/thermostat. Circled in red in that picture its pretty identifiable, so I am going to do that one hose there and connect it to the three way junction you can't see in the picture that splits off to the firewall presumably presumably connecting to the outlet. That certainly takes out one of the steal pipes that runs its zig zag course along the engine and won't alter any of the flow directions at either of the junctions.. I already have the new hose anyway and that alteration will only involve one clamp at each end. Even if its not exactly what you guys did it certainly keeps things as they are except for one flow route through a stele pipe I can plainly see will no longer get zig zag. I'll update the results.

 

The rerouting work like a charm.

Now my Uplander gets so hot so quick I have to turn the setting to either off, or the lowest it can go.

Its fair to say I went my own way on the rerouting rather than follow the exact above instructions.\

Also My vast improvement is credited to the rerouting of just one of the pipes along the engine.