Topic: Lower radiator hose replacement
in Forum: C3 Cooling and Heating Systems
Already a Member?
Click Here to Login
Not yet a Member?
Click Here to Register for Free!
good morning all!
As I was going through my 1973 to get her ready for storage, I noticed a bulge in the lower radiator hose. Started her up and sure enough I found coolant on the ground. Had the system pressure tested just to make sure nothing else was going on and everything checked out so I'm guessing the bulge in lower rad hose is culprit. Pretty expensive to have my garage fix so This newbie would like to attempt. I had a few questions/comments:
The forum seems split on whether or not I need the coil lined hose. Suggestions?
Dish soap seems the preferred method to slip new hose on.
Is removing fan shroud recommended to switch lower rad hose?
Proper procedure on refilling with coolant? Car running, car off, directly into radiator, radiator resivoir, how much coolant etc?
I've googled and youtubed for a step-by-step and have not found anything worthwhile.
As always, thanks in advance kind Corvetters!
"You know, we always called each other goodfellas. Like you'd say to somebody: You're gonna like this guy, he's all right. He's a goodfella. He's one of us. You understand?"
SPONSOR AD:: (Our Sponsors help support C3VR)
Raise front end up high enough to crawl underneath via ramps or jack and jack stands.
|UPDATED|11/14/2014 9:34:12 AM (AZT)|/UPDATED|
Remove radiator cap. (engine cold)
Take a empty bucket/container and pliers under car.
Place bucket under petcock. Use pliers to gently open the petcock and drain radiator.
Loosen hose clamps and slide them out of the way.
Use a radiator hose removal tool to help break the bond between the hose and the radiator neck/waterpump neck. If you can find a tool use a razor knife to slice the hose ends so you can peel them off. Don't cut yourself.
Place hose clamps over new hose (w/coil), then slide into place. Vaseline will help slide the ends on.
Tighten clamps.
Close drain petcock.
Refill system with universal 50/50 premixed antifreeze.
Start car and let the system bleed out the air with the radiator cap off.
Set you heater controls to defrost. When you get heat from there you'll know the heater core is free of air pockets.
Keep a close eye on the temperature gauge. If it starts to rise. Blip the throttle to help push air pockets out of the cooling system. Feel the upper radiator hose. If it gets warm or hot the thermostat has opened. If it keeps rising dangerously, shut it down and let it cool off. You'll probably have antifreeze spitting out the filler neck.
Once the system is bled, top off the radiator, install the radiator cap. check for leaks.
Retighten the hose clamps.
Top off the overflow bottle and take it for a ride.
Then recheck for leaks.
Good luck!
While your under there check for leakage around the water pump to rule out any possible leaks there.
This is a picture of a radiator hose removal tool.
|UPDATED|11/14/2014 9:34:12 AM (AZT)|/UPDATED|
TKO500 5 spd.
Borgeson Steering Box
Born 8/1981
Sequence #3975
Click here to see more pics of my Vette on CarDomain.
Lifetime Member #26
Well, I hope you have small hands. In the factory that hose was installed before radiator, rad. frame and body were put on. Easy for them...!!! I had the shroud off, lower right grill out, and then had to loosen the radiator frame on both sides, just to get enough room to get my hands and hose in there. I swore never again!!!!! I had the engine out and should have put it on motor before reinstalling. You do what you have to do. I went org. hose for replacement. But I have keep everything as org. as I could, or money permitted.
Sarge81 said:
Raise front end up high enough to crawl underneath via ramps or jack and jack stands.
Remove radiator cap. (engine cold)
Take a empty bucket/container and pliers under car.
Place bucket under petcock. Use pliers to gently open the petcock and drain radiator.
Loosen hose clamps and slide them out of the way.
Use a radiator hose removal tool to help break the bond between the hose and the radiator neck/waterpump neck. If you can find a tool use a razor knife to slice the hose ends so you can peel them off. Don't cut yourself.
Place hose clamps over new hose (w/coil), then slide into place. Vaseline will help slide the ends on.
Tighten clamps.
Close drain petcock.
Refill system with universal 50/50 premixed antifreeze.
Start car and let the system bleed out the air with the radiator cap off.
Set you heater controls to defrost. When you get heat from there you'll know the heater core is free of air pockets.
Keep a close eye on the temperature gauge. If it starts to rise. Blip the throttle to help push air pockets out of the cooling system. Feel the upper radiator hose. If it gets warm or hot the thermostat has opened. If it keeps rising dangerously, shut it down and let it cool off. You'll probably have antifreeze spitting out the filler neck.
Once the system is bled, top off the radiator, install the radiator cap. check for leaks.
Retighten the hose clamps.
Top off the overflow bottle and take it for a ride.
Then recheck for leaks.
Good luck!
While your under there check for leakage around the water pump to rule out any possible leaks there.
This is a picture of a radiator hose removal tool.
Dang Sarge! I'm impressed. Been in the rad business for 43 years and couldn't have said it better meself. Lookin for a job in Michigan??
Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
Sarge81 said: ...use a razor knife to slice the hose ends so you can peel them off. Don't cut yourself.
That's the BEST way to get old hoses off of radiator or heater cores.....keeps you from damaging the necks, or possibly cracking the soldered joints on the radiator.
(I think Darryl must write repair instructions for Mitchell or something....that was great!)
I'm not big on using petroleum products to make hoses go on easier, due to the fact that oils/greases can soften the hose over time....it also makes it harder to get a tight seal. I use a little straight antifreeze inside the hose ends. It's slick, and will squish out a little easier when tightening the clamps. That's just me. Lots of folks use Vaseline, wheel bearing grease, WD-40, whatever, and it accomplishes the task at hand(getting the hose on) just fine.
As far as spring/no spring in the lower hose, you NEED that spring in there. And that's all I have to say about that....
Good luck with your project. Have patience....that hose ain't gunna just fall off, nor will the new one magically suck itself back on...it's gunna take some finagling, some head scratching, and a few well placed curse werds, but it can be done without dis-assembling the whole front end. Just take yer time....and have a huge drain pan in place, 'cause you WILL make a mess.
Joel Adams
C3VR Lifetime Member #56 
My Link 
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Sarge! Hats off to you, sir! I followed your excellent step-by-step and got the lower rad hose off without removing anything else!!! It wasn't easy, but with a little maneuvering, and a few careful razor slices, she came off! I was even able to flush the system three times before removing hose. Feeling like a man today! As you can see, the old hose was quite old and the spring was rotten. I shudder to think of the debris washed into my system from the rotting spring :0
See below...the numbers are: GM 331855 AJ GATES
I wasn't able to get the new hose back on today. Started getting too late. I pushed the vehicle back into the garage. The temperature is supposed to really drop here in southern Wisconsin. Around 20 degrees or so. Should I be concerned about having no coolant and no lower rads hose attached?
Finally, the new rad hose I purchased did not come with an internal spring. Called a corvette shop near me looking for a spring or a spring/hose combo and he said I do not need the spring, that he sometimes adds the spring and sometimes he does not...with no rule of thumb. Your thoughts?
Again, thank you for the awesome support!!! :)
"You know, we always called each other goodfellas. Like you'd say to somebody: You're gonna like this guy, he's all right. He's a goodfella. He's one of us. You understand?"
Limited Member
Send PM
Overland Park, KS - USA
Joined: 7/9/2003
Posts: 914
Vette(s): 1973 Orange Metallic Coupe (orig owner), L82, 4 spd (WR), PS, (A/C & PW (I installed from wrecked 73)), leather, AM/FM Stereo, ran with '65 FI unit earlier & will again some day.
2023 Accelerate Yellow HTC Stingray
You definitely need the spring in the lower hose. Since the lower hose is on the suction side of the water pump, the spring prevents the hose from collapsing as previously mentioned.
1973 L-82 4 spd
Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
That's the original hose for the car....kewl!
And again....you DO need the spring. Get a hose with the spring, or buy a cheapo generic hose that does have the spring, and install it in the one that fits the car.
And again....you DO need the spring. Get a hose with the spring, or buy a cheapo generic hose that does have the spring, and install it in the one that fits the car.
Joel Adams
C3VR Lifetime Member #56
My Link
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
The one time in my life I was glad I have small hands! 
I'm sure getting the new lower rad hose back on will be another animal all together...
"You know, we always called each other goodfellas. Like you'd say to somebody: You're gonna like this guy, he's all right. He's a goodfella. He's one of us. You understand?"
in Forum: C3 Cooling and Heating Systems
SPONSOR AD: (Our Sponsors help support C3VR)