73 recovery tank, etc.

[Douglas C.]

On my 73, see pics. Fluid in tank very low, radiator fluid ran out when cap removed, pic is after sucking enough out away from radiator overflow tube. Hose to tank not clogged. Cap arrow not aligned with overflow tube. Would cap not twisted in line cause a problem, am I overfilled in radiator? AIM says to put .5 gallon of fluid in tank. Car does not run hot, fluid in tank never changes cold or warmed up. Thoughts?
Doug

[James G.]

Re: 73 recovery tank, etc.

Nice to see an original RC33 with the correct wording "DO NOT OPEN"
The later replacement RC33 has "NEVER OPEN HOT"

[Douglas C.]

Re: 73 recovery tank, etc.

Nice to see an original RC33 with the correct wording "DO NOT OPEN"
The later replacement RC33 has "NEVER OPEN HOT"

I was also glad to see the original 334762 recovery tank. I cleaned it and put in .5 gallon of coolant per the AIM. Since it was empty I wonder if that is why my temp gauge is not reading accurate. Have to take a ride and find out. 20220228_174901.jpg20220228_174948.jpg20220228_182037.jpg

[Mark E.]

Re: 73 recovery tank, etc.

System is designed to capture overflow coolant when pressure builds past cap's rated pressure. Then overflow coolant is drawn back into radiator when system cools and coolant contracts. This eliminates air in cooling system and coolant loss.
For this to work, cap must be fully seated with arrows aligned. So I would start with fixing this issue then see if system works properly. If it's not obvious why cap will mot align (bent radiator neck or damaged cap), try another cap.

[Douglas C.]

Re: 73 recovery tank, etc.

System is designed to capture overflow coolant when pressure builds past cap's rated pressure. Then overflow coolant is drawn back into radiator when system cools and coolant contracts. This eliminates air in cooling system and coolant loss.
For this to work, cap must be fully seated with arrows aligned. So I would start with fixing this issue then see if system works properly. If it's not obvious why cap will mot align (bent radiator neck or damaged cap), try another cap.

Ok, I cleaned recovery tank, added new rubber lines, and twisted radiator cap tight which aligned arrow. Then added .5 gallon coolant per AIM. Ran car in driveway and I do now see a little green coolant showing in top cover tube of recovery tank. See pics. Temp gauge reads around 230, but infrared gauge on thermostat neck around 170. So next I will try a new Lectric Limited sender which is supposed to be a correct read. Car just never runs anything close to hot.20220303_151527.jpg20220303_151557.jpg20220303_151538.jpg

[Mark E.]

Re: 73 recovery tank, etc.

Progress! As a final check, after a couple of heat cycles remove the radiator cap when the engine is cold. If working properly, the radiator will be completely full.

I suspect the issue was the cap wasn't fully twisted in place.

[Douglas C.]

Re: 73 recovery tank, etc.

Progress! As a final check, after a couple of heat cycles remove the radiator cap when the engine is cold. If working properly, the radiator will be completely full.

I suspect the issue was the cap wasn't fully twisted in place.

Thanks, I figured at this point drive it and enough heat and cold cycles should eliminate any possible air pockets. Overall I still think GM realized this car's temp gauge and /or sender were just not right. See pic of owners manual saying 230 is normal, if hits 250 just put in neutral and rev engine. I can't imagine they would build any car to run at 230 -250 with a factory warranty. Head gaskets would never last. 20220303_160654.jpg

[James G.]

Re: 73 recovery tank, etc.

In the first photo I noticed the original "knuckle cutter" spring clamp on the radiator overflow hose. (sharp squared ends)
These are the correct style spring clamp for the 1973 model year.
The type with the rounded ends are a newer design and will probably cost points in Flight Judging.

[Douglas C.]

Re: 73 recovery tank, etc.

In the first photo I noticed the original "knuckle cutter" spring clamp on the radiator overflow hose. (sharp squared ends)
These are the correct style spring clamp for the 1973 model year.
The type with the rounded ends are a newer design and will probably cost points in Flight Judging.

Thanks, good point. It was kinda grungy so I put on a newer clamp for now. I'll clean up the original. Am I correct it should be a flat black coloring?