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2003 STS
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10 Posts
Discussion Starter #1 (Edited)
I have changed the thermostat, temp sensor, flushed and refilled radiator with 50/50 Dexcool, replaced the surge tank cap, cleared small amount of corrosion from metal bolt and hose returning to expansion tank, just completed the block test twice and it did not change to yellow. I don't see any leakage and have not had to add but a small amount of fluid every few months.

I did notice that when i was doing the block test that once the thermostat opened the Dexcool would overflow the surge tank. Is this common for a pressurized system?
 

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Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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70,718 Posts
Correct surge tank (not "expansion" - different type system) level is 1/2 full, cold. See the FULL COLD legend and arrow molded into the tank.

"....change to yellow" - did the fluid have ANY color change from the original blue?If so, possible exhaust gases in the coolant. (If ANY coolant got into the tester/fluid it must be washed in clean water and the test repeated - you sample the airspace over the coolant, not the coolant itself.)

Is the purge line flowing a small stream at idle? (That's the short line to the top side of the surge tank)

Is the water pump drive system functional?

Are the heater core inlet and outlet hoses hot?

Water crossover assembled.gif
water pump drive pulleys.gif
Coolant tank fill legend.jpg
 

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2003 STS
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10 Posts
Discussion Starter #3
Thank you for the very detailed response..

Tank was filled to the line indicated by the arrow when cold.

There was no color change in the fluid, i pulled the tester out before coolant got into it. Ran the test twice.
I removed the small hose going to surge tank and lowered it down and coolant was flowing a steady stream through the tube and hose into a bucket without engine running since it did i did not try it again with engine running.
The water pump belt, tensioner and pully are all in good shape i replaced the belt and idler pully about 18 months ago.
I didn't feel of the heater core hoses to see if they were hot but i had the heat on high when i was doing the radiator purge and it was very hot air coming out.
 

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Super Moderator
2010 DTS
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87,433 Posts
I did notice that when i was doing the block test that once the thermostat opened the Dexcool would overflow the surge tank. Is this common for a pressurized system?
Yes.
Remember, when the cap is off, the system is no longer pressurized and the boiling point is lowered from around 260° down to about 226° .You can only run it for a short time with the cap off before it boils over.
 

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2003 STS
Joined
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10 Posts
Discussion Starter #5
Thanks for your help, I finally got back to working on this issue and verified the heater hoses were both hot...I decided to pull the water pump and I was shocked by what I found, I don't know how it ran as long as it did before getting hot. I bought this car when it had 85k on it now it has 125k. I've never seen one so degraded! It never made any noises, i can only assume the guy i bought it from may have taken some pieces out? Have you ever seen anything like this?
585601
 

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Administrator
2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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70,718 Posts
THAT is a new one in here - at least since the site start in 2002 !!!!

There was a pretty rusty and degraded Northstar pump here about 15 - 17 years ago but nothing like that.

I wonder where the vanes and shroud are - if they even still exist ? The shroud itself is on the pump cover side, so there's no way it could have got past the remains of the impeller blades. Strange.

Hmmmm ........... do I recall an old thread in which a Northstar water pump shed the shroud and made nasty noises?

water pump capsule 2.jpg
water pump capsule.jpg
water pump in crossover.jpg
 
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