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I'm having an issue with my coolant overflowing from my reservoir tank. After doing lots of searching, most people report crossed coolant lines causing this, or a bad radiator cap.
Radiator and cap are both new.
Does anyone have a 1993 coolant hose diagram? The one on Shoebox's site appears to be for 1995-1997.
You can also have a problem if you have a hole in the overflow line from the fill neck to reservoir.
Radiator heats up, fluid expands, overflows into the reservoir. If the overflow line is intact, as the radiator cools down, vacuum pulls coolant from the reservoir to keep the radiator full. If the flexible line or the metal tube is connects to under the battery has a hole, this can’t happen. Radiator will be low. Refill the radiator, and the process repeats, eventually the reservoir overflows.
shoebox, Injuneer, JakeRobb - Thank you so much for your reponses.
Sadly you're absolutely right about never trusting new parts. Just to be sure, I installed a new AC-Delco cap yesterday. Still the same problem
Injuneer - that's very interesting about the overflow line. I just removed it and could not see any obvious holes, but the line is very old. Is this a part that is still available for purchase?
When I fill the radiator up, coolant usually only overflows out the reservoir immediately after a long drive on the highway. City driving doesn't seem to affect it as much.
Something else I noticed was when I try to bleed the system, this bleeder screw does not have any coolant coming out. Only the bleeder screw on the thermostat housing does:
Any ideas would be greatly appreciated - I want my bird back
Coolant flow to and from the heater is always “on”, and flowing through the heater core. There is no shut off valve for the core. When the heater control is in the “off” position, only the air flow is blocked. There is a “flow control valve” (but it is only an orifice) in-line to limit flow, but that does not limited bleeding the air. See part #13 in the heater hose diagram.
If the heater core is plugged with sludge, bleed may not work. If that's the case, the heater return line will not get hot, and core needs to be flushed with a garden hose.
We had a thread about the overflow hose/pipe earlier this year. I believe it was discontinued. I suggested replicating the tube with bent copper tubing. Use reinforced (vacuum service) rubber hose for the upper part. See if you can find the thread w/ a “search”.
Put your finger over the end of the old pipe, try and pull a vacuum on the end of the hose. MityVac would be useful.
05-25-2018, 04:01 PM
