A friend’s 1997 Chevy Astro had some understandable problems after 197,000 miles and over ten years of service. It also had some not-so-understandable problems.
In the course of repairing some wiring, I noticed that the coolant in the reservoir looked very different from the coolant in the radiator. The reservoir looked great, the radiator was filthy.
Hmm. There must be an obstruction or problem somewhere.
Check the connecting hose? It was unobstructed. Will compressed air clear the obstruction in the reservoir? Nope.
OK – I removed the reservoir for inspection, with particular attention to the squarish section between the small hose spigot and the bottom of the tank. When I tilted the tank, the orange coolant would move most of the way up that passage, but not all the way. The passage that should have gone all the way through – didn’t.
Can’t get air through passage, can’t identify any contamination or debris in the passage. What ???!!!!
Try drilling through the passageway? I got plastic shavings, but couldn’t make it through due to the way it’s configured. The passage is blocked by original plastic. As far as I can tell, it was made wrong at the factory, and never could have worked.
How many dealer visits and repair shop visits must have occurred in ten years and 190,000 miles? Quite a few. Did anybody notice? NONE of them caught it.
For now, the hose just goes into the fill opening, and that works.