Cooling system fill

[mmkkpro]

Hey guys, I just wanted to post a quick solution to filling the LT5 cooling system. This is a air lift/test tool, it works off your air compressor. It creates a vacuum in the cooling system and sucks coolant back into system. I was worried about having a trapped air pocket so I bought this and it works great. Hope it helps someone. I have a little YT channel where I post a little about it under my name, Michael Proulx.

[Ccmano]

That’s cool, haven’t seen one of those. How exactly do you use it?

I have found a cooling system fill funnel to work very well. It allows the thermostat to completely open expelling most of the air and not making a mess of spilled coolant. If I suspect an air bubble I use a cooling system pressure tester to pressurize the system and move the bubble out as in the latest Haibeck method.
H
:cheers:

https://farm66.staticflickr.com/65535/49817752051_2f252c7c3b_c.jpg (https://flic.kr/p/2iUe14v)

[HAWAIIZR-1]

Thanks for sharing and taking the time to do a video. It’s always nice to hear of options. I’ve been doing the jack up passenger side method all these years. On my 90 I modified the plumbing with a bleed valve at the highest point in the system and it worked well. Who is Leroy!! [emoji38] Thanks again!


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[HAWAIIZR-1]

That’s cool, haven’t seen one of those. How exactly do you use it?



I have found a cooling system fill funnel to work very well. It allows the thermostat to completely open expelling most of the air and not making a mess of spilled coolant. If I suspect an air bubble I use a cooling system pressure tester to pressurize the system and move the bubble out as in the latest Haibeck method.

H

:cheers:



https://farm66.staticflickr.com/65535/49817752051_2f252c7c3b_c.jpg (https://flic.kr/p/2iUe14v)



Thanks Hans! And yet another cool method I might have to try.


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[mmkkpro]

Hi guys,
First drain coolant, close petcock.
Choose proper grommet for where radiator cap goes, insert tool, tighten, close coolant fill valve.
Connect air hose at 90 lbs to vacuum side of tool, make sure vacuum valve is closed. With shop air attached open vacuum valve, draw system completely down, mine went to-26inhg,shut valve, allow a couple minutes to see if system holds vacuum. It will collapse hoses. Remove shop air hose.
Fill 5 gal bucket with fresh coolant, have more than you need. Insert coolant hose of tool into bucket, take care to remove any air bubbles from hose. With hose in bucket open fill valve, it will draw coolant back into system, you can watch the Gauge on the tool drop to zero, done.
Remove tool, it will be full.
Seemed to work great, I had 4.5 gallons of coolant in the bucket, more than I needed. I have seen guys do it straight from 1 gal coolant jugs, but I was afraid of introducing air into the system while switching jugs. It sounds like a lot of work but actually went pretty fast.
I watched several YT videos on the process, before I bought the tool. I figure I can use it on other projects also.

[Ccmano]

Hi guys,
First drain coolant, close petcock.
Choose proper grommet for where radiator cap goes, insert tool, tighten, close coolant fill valve.
Connect air hose at 90 lbs to vacuum side of tool, make sure vacuum valve is closed. With shop air attached open vacuum valve, draw system completely down, mine went to-26inhg,shut valve, allow a couple minutes to see if system holds vacuum. It will collapse hoses. Remove shop air hose.
Fill 5 gal bucket with fresh coolant, have more than you need. Insert coolant hose of tool into bucket, take care to remove any air bubbles from hose. With hose in bucket open fill valve, it will draw coolant back into system, you can watch the Gauge on the tool drop to zero, done.
Remove tool, it will be full.
Seemed to work great, I had 4.5 gallons of coolant in the bucket, more than I needed. I have seen guys do it straight from 1 gal coolant jugs, but I was afraid of introducing air into the system while switching jugs. It sounds like a lot of work but actually went pretty fast.
I watched several YT videos on the process, before I bought the tool. I figure I can use it on other projects also.

I’m going have to add that tool to my arsenal. Sounds like it should eliminate the air bubble problem areas around the water pump since your basically evacuating the system of air before your fill. Very cool. Where did you get it?
H
:cheers:

[Ccmano]

Thanks Hans! And yet another cool method I might have to try.


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FYI, I still jack that side of the car up while using the funnel. It works very well. I’m going to buy this other tool, it sounds like it might be the perfect solution.
H
:cheers:

[mmkkpro]

Harbor Freight 63.00 bucks with 20% coupon.

[HAWAIIZR-1]

Thanks Michael and Hans! Yes! I agree this is a pretty sweet method!


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[secondchance]

Way I change coolant is, I jack up the car using factory jack on the passenger side, slide in a large 6” high plastic storage container I bought at Bath and Beyond under the thermostat housing, unbolt thermostat housing (I had it heli-coiled many years ago), separate the housing, drain coolant, disconnect at heater hose by the coolant tank, back flush with water hose, bolt back thermostat housing, two gallons of coolant, top it off with distilled water while still jacked up.
Fill over-flow reservoir with distilled water drive for about 10 minutes and add more distilled water as needed.
Never had any issue with trapped air.

[mmkkpro]

That's cool secondchance, this is my first Z and I was freaking out a little over air being trapped. I ran across this air lift tool and figured I'd give it a try. I have read that if you can see coolant flowing from the little brass tube in the metal tank that means the water pump is pumping. I'm learning a ton here at the registry, hopefully as I learn more about these cars I can give back some of the help I have received. I just put new coils, wires and plugs in it, I had a slight miss and stumble off idle, took her up the road earlier and she felt good. I got a ways to go but getting there.

[secondchance]

One word of caution - when I first unbolted thermostat housing, bolt wiped out the thread and had to be helicoiled. Maybe corrosion between the bolt and the housing due to different metal?

Yes. Coolant flow coming from the brass tube is confirmation of the water pump working.

[mmkkpro]

I have not worked on the thermostat yet, so far seems to be working fine, temp Gauge is just above center. However this car sat for several years with cooling system open, hoses unhooked and marvel mystery oil in cylinders. I'm having an issue with the MM in the exhaust system, as it heats up, smokes and it leaks from exhaust connections, I mean it pools on my garage floor. I reckon maybe the valves were open on a few cylinders and the guy kept filling and it just went strait into exhaust. I have not actually driven it at speed for a long distance yet, I hope when I do so it will burn out but not sure what's going to happen to the cats. I have new o2 sensors. Headers and exhaust at some point this summer. I still have a long list, seat covers, weatherstripping, paint, have wheels refinished and so on. Have no idea when it was last tagged and on the road, 78k miles, it is all here nothing butchered, just neglected for some years. The guy I bought it from got it from original owner and it lived in SC. If you want check out my YT channel, under Michael Proulx, nothing fancy just some project updates. Getting back to the T housing, dissimilar metals especially bolts do cause problems, it's so humid here I'm sure I'm going to have to be very careful with it. Have a great day.

[Matt B]

Michael, know it's already been a while ago, but thanks for that great hint! I never heard about these, so far all my cars had self bleeding cooling systems. I dug a bit into the matter and apparently it's very common and even needed e.g. for some Porsche or BMW which seem to be impossible to bleed without such a tool. Nice! If it even tames a Porsche than it's great for a ZR!

One question to all: I'm thinking about cleaning the system with radiator flush or something similar. I bet my coolant is way overaged. But if the ZR cooling system is so prone to air bubbles, (how) can I flush it properly to remove any cleanser residue? In all my other cars I just remove the thermostat, squeeze a garden hose into the system and open the tap for a while. Doesn't sound as I can use the same process on an LT5, can I?
Or should I skip the cleaning and just drain/refill with fresh coolant? Any recommendations?

[1991 Corvette ZR-1]

Being somewhat lazy, I bought a water heater drain pan, so it is low profile enough to get under the car without having to raise it. Works great for oil changes. Never used it for coolant draining but, it would work just as well. Whenever I drain the coolant system and need to refill, I fill as much as possible while it is on all four wheels. Then when it looks like no more air is bleeding out, I use a jack on the frame under the passenger window and I lift the whole side up as high as I feel comfortable doing, which is surprisingly tipped up pretty high.

I then pour in more coolant as I can and then I lower the car back down. Start it up and watch for the flow of coolant to begin from the tube inside the tank. I also touch the coolant tubes to feel for warmth. I have been told if the cam covers feel warm or hot and the coolant tubes do not, there is an air lock in the system. If the tubes are warm/getting hot but the cam covers are still cool to the touch, everything is working as it should. I do three short 5-6 mile drives after a system refill, each time letting the engine cool down completely. After the first drive, I add extra coolant to the overflow tank to be pulled back into the system if needed.

Never had an issue doing it this way and I have done it more times than wish I had in only three years of ownership.