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I have a question about flushing the coolant in my ’95 z28. I’ve been having an overheating problem that I suspect to be the water pump but before I swapped that out ETCG suggested bleed any air out of the cooling system in the hopes that was the problem. My coolant level is right on the money according to the stick but I don’t see any coolant under the cap after running the engine much less getting an overflow. When flushing the system are you supposed to add that much over or is something wrong here? I took my thermostat out, too, by the way.
The day after I attempted to bleed the cooling system I got home from work and when I shut the engine off I heard coolant sloshing around in the engine. Did I just force more air into it?
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couple of problems here.Put the thermostat back in. It regulates
engine temp.when you refill the cooling system.it should be right
to the top of the radiator neck.You say you have no flow.if coolant
can’t be seen,then you won’t see flow.got two videos for you.When i change my coolant i use a vaccuum refiller like the one in the attachement.
It is a really usefull tool. it helps you …
1: test for leaks in the coolant system (when you loose vaccumm you have a leak)
2: refill the whole coolant system without any air bubblesthey dont even cost much. I got mine for 70€
Hey thanks guys. Two more questions : Should the coolant be at the neck of the radiator cold? Either I’m super low on coolant or I’m assuming the worst. And can I rent those pressure pump things at like Autozone?
when the engine is cold and the system is full.
The coolant should be right at the neck of the radiator.
As for renting that pump.Don’t know. I use the bleeding
procedure in the video.Minus the spill proof funnel.working
on getting one. 😉Hm. My Camaro holds 4.75 gallons and I’ve already put in 2 gallons plus what was already in there. I find it hard to believe I was missing that much without a major leak. My oil pressure is normal so I feel like there isn’t an internal crack. That’s why I want to get a hold of one of those pumps to test for leaks.
Heres a good video of testing and refilling your coolant system with an air tool
[video]http://www.youtube.com/watch?v=ZOIiqyVx59Y[/video]
I had a 94 Z-28 and this system on the LT-1 engine uses a reverse flow water pump—essentially backwards from all past Chevy small blocks. This system is notorious for trapping air when you do a flush and re-fill. Chevy was smart (for a change!) and installed a bleed screw right around the thermostat housing. Make sure you have a new thermostat installed—DO NOT run without one since this motor runs based on temperature and it is critical to maintain the correct temp. With the car running, loosen the locknut and slowly back out the bleed screw until you hear air hissing. Close the screw when you get coolant trickling out. Do this a couple of times after it is warmed up to operating temp. Add coolant as necessary through the coolant reservoir mounted on the fender—it will draw it into the system as needed.
Never got around to pressure testing the system but I found the leak under my passenger side dash. I’m gonna take a look at it tomorrow if it’s not too rainy.
You might think twice about that because often to replace a heater core you need to remove the dash assembly. I’m glad you found the leak. What you described before you found the leak was text book air in the cooling system. In your case created by the leak you had at the heater core. I only mention this for future reference. Air in the cooling system is the #1 cause of cooling system problems and should be the first thing to check when dealing with an overheat condition.
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