Hi, I have a 94 Z28 with the LT1. In April I had a shop do a tune up, and they also replaced some coolant system items like water pump gaskets, coolant and hose clamps, so they bled the system and topped it off (all of this on the paperwork). When I drove it home, the low coolant light came on, but the reservoir stick showed coolant level normal. But I could see in the radiator it was a little low. I called the shop and they said the system is probably still just burping, go ahead and add some coolant. Luckily I had the right kind on hand. I asked isn’t it odd the reservoir looks normal according to the stick, he said reading that stick is really tricky. Ok, I said, it only took about a cup and a half of antifreeze in the radiator and everything’s been fine until today, same thing happened. Low coolant light came on. Reservoir looks like it’s at normal, but radiator took about a cup or two of antifreeze.
There are no signs of any leaks. I’ve got a pit in my stomach that maybe there’s antifreeze getting into the engine oil and getting burned up so I don’t notice, because I know that would be really bad news. But maybe there’s something wrong between the reservoir and the radiator? The same shop is doing the control arms this Friday so I’m going to ask them to check it out.

 

I would ask your shop to do a pressure test of the cooling system to see if the system loses pressure over time. Could be something as simple as a bad radiator cap or a loose recovery tank hose connection. If the system isn't sealed, it won't recover any of the antifreeze pushed out of the radiator to the overflow tank cause by heat expansion. This condition could create a low level in the radiator as you describe and not show any noticeable leaks. As long as there is antifreeze in the overflow tank and it's above the hose inlet, coolant should be pulled back into radiator to maintain the proper level because of the vacuum created as the system cools down.

 

Thanks, I will ask them. From what I’ve read the return lines are prone to leaks over time, at least that’s what I’m hoping, because the alternatives are a little scary! Not to mention expensive!
p.s. I haven’t been monitoring closely enough to know if reservoir tank level has increased, but I’ll start now.

 

yep pressure test should tell you if there are problems in the system. could just be getting the air out, the lt1 can be a pain to get all air out. when bleeding air out of system its best to have car at an angle with the front up as high as you can,,, well within reason, lol. have them test radiator cap as well, bad cap can let coolant into overflow tank then suck air back into the radiator. check oil on dip stick and look for any droplets of water on it, last thing you want is to run engine with mix of anifreeze in oil, once it mixes and heats up it turns milky sorta color and the antifreeze will go acidic and do damage to bearings.

 

Thanks, when I added antifreeze to radiator yesterday I checked the oil and didn’t notice anything unusual, crossing my fingers it’s all related to when they bled the system in April . Seems like too much of a coincidence that now I’m having this issue, fingers crossed it’s a simple fix.

 

Looks like I found the culprit, I remove the battery and can see a little antifreeze down in where the return line joins to the reservoir. Hopefully the shop doesn’t have too much trouble replacing this piece.

Is this Little metal tube still available to order I hope?
update: called my local Chevy dealer and he found part at sixity auto .com that indicates it’sa replacement for the gm part number, but it’s rubber. It was only $20 with free shipping so I said what the heck and ordered it. We shall see.
update #2 (if anyone cares&#128515 I didn’t have a lot of confidence that rubber hose was really what I need, so I jumped onto eBay and found an entire reservoir tank assembly, including all the hoses, off a Camaro in Florida, so hopefully it’s not corroded. Pics looked good and it was only 50 bucks for the whole shebang so hopefully between the two orders I made today I’ll get what I need!

 

It looks like you old reservoir has a broken battery grip, so you're killing two birds with one stone replacing the assembly. I can't see the old hose well enough to know, but are there a couple pin holes in short kick of the tube just before the tube turns down into the tank? I wonder if that could be repaired with something like an aluminum type welding rod that is heated with a butane torch that I've seen advertised on Facebook?

 

Yeah good eye, I actually use zip ties to keep the battery from sliding around! What a ridiculous design by gm to run the return under the battery! They really crammed the lt1 engines into these cars!

 

kool, very lucky to find one, not easy to find a good one. the metal pipe can get ate up by leaking battery acid and that spot seems to be a moisture magnet, better give that bolt a squirt of lube and let it soak while you wait for part.

 

Do you mean the bolt holding down the battery tray?