The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 04-14-2011, 12:33 PM   #1
Tuff Gong
Registered User
 
Tuff Gong's Avatar
 
Join Date: Jan 2011
Location: Glendale, AZ
Posts: 3,178
radiator question

Looking for a little help. I went for a nice drive the other day. When I got home, I left it running in the driveway to open the garage and take care of a few other things before I parked it for the night. That’s when I noticed that my coolant was leaking out of my overflow tube on the radiator. I popped the cap when it cooled down and it was about ¼ low. Any ideas as to why this would happen? The truck never really got hot, it least the gauges didn’t show. Should I be worried? Thanks.
Tuff Gong is offline   Reply With Quote
Old 04-14-2011, 01:01 PM   #2
Shyguy
Junior Member
 
Shyguy's Avatar
 
Join Date: Dec 2006
Location: Southeast Missouri
Posts: 2,436
Re: radiator question

You may need a new radiator cap. When you say 1/4 down do you mean 1/4 down in the radiator.

I usually keep the level a couple of inches down from the top of the filler neck. After a while it will leak out of the over-flow tube until the levels gets down about that level.

Some people have gone with over-flow tanks and relief/recovery caps because they don't like antifreeze getting onto the ground.
__________________
'67 Chevy C-20 short stepper - build complete, 454/SM-465.
'75 C-30 Single Cab DRW-350 small block/NP-435.
'77 GMC-6500 Dump Truck, 427 Tall Deck.
'92 GMC K-3500 Duallie, 454/4L80E.
Shyguy is offline   Reply With Quote
Old 04-14-2011, 02:05 PM   #3
Tuff Gong
Registered User
 
Tuff Gong's Avatar
 
Join Date: Jan 2011
Location: Glendale, AZ
Posts: 3,178
Re: radiator question

Quote:
Originally Posted by Shyguy View Post
You may need a new radiator cap. When you say 1/4 down do you mean 1/4 down in the radiator.

I usually keep the level a couple of inches down from the top of the filler neck. After a while it will leak out of the over-flow tube until the levels gets down about that level.

Some people have gone with over-flow tanks and relief/recovery caps because they don't like antifreeze getting onto the ground.
I may have over stated on the 1/4 way down in the radiator. Its more like an inch or two. I topped off the coolant a few days agos to the tippy top. After reading your response, I believe that it is just leaking out the overfloow tube until it gets to the right level it wants to be at, just like you said. Thanks for the help.
Tuff Gong is offline   Reply With Quote
Old 04-14-2011, 01:07 PM   #4
todd99
Registered User
 
Join Date: Feb 2011
Location: prescott, az
Posts: 225
Re: radiator question

I went with an over flow tank because as the truck cools down it should pull the coolant back into the radiator.
__________________
1971 C20 Longhorn Custom Camper
todd99 is offline   Reply With Quote
Old 04-14-2011, 01:14 PM   #5
dmack91
Registered User
 
dmack91's Avatar
 
Join Date: Jan 2011
Location: Redmond, OR
Posts: 760
Re: radiator question

Quote:
Originally Posted by todd99 View Post
I went with an over flow tank because as the truck cools down it should pull the coolant back into the radiator.
Same here. I got one at NAPA for $7.50 that fit between the battery and firewall. Works great.
__________________
68 Chev C20- son has it now
83 K20 - bought from son
70 C20 - in progress
dmack91 is offline   Reply With Quote
Old 04-14-2011, 01:57 PM   #6
cdowns
Senior Member
 
cdowns's Avatar
 
Join Date: Jan 2003
Location: daytonabeach
Posts: 22,956
Re: radiator question

Quote:
Originally Posted by todd99 View Post
I went with an over flow tank because as the truck cools down it should pull the coolant back into the radiator.
wont work properly with the original radiator cap// you need new style for closed system

loads of coolant is lost because people just dont know the proper way to fill a radiator on and old vehicle
__________________
71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane

MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF

DONT BELIEVE EVERYTHING YOU THINK

TAKE MY ADVISE;I DON'T USE IT ANYWAY
cdowns is offline   Reply With Quote
Old 04-14-2011, 02:40 PM   #7
DANTIP
Registered User
 
DANTIP's Avatar
 
Join Date: Sep 2001
Location: Fort Wayne, Indiana, USA
Posts: 1,889
Re: radiator question

I agree, if the radiator cap spring gets weak it will open at a lower pressure and spill coolant when it shouldn't. By the way, the cap can be tested (some auto parts houses will do it for free).
DANTIP is offline   Reply With Quote
Old 04-14-2011, 04:42 PM   #8
Longhorn Man
its all about the +6 inches
 
Longhorn Man's Avatar
 
Join Date: Jan 2001
Location: Hilliard Ohio
Posts: 2,693
Re: radiator question

As implied, this is normal, and the rad is supposed to be filled to an inch or so below the filler neck.
Longhorn Man is offline   Reply With Quote
Old 04-14-2011, 06:48 PM   #9
68gmsee
Active Member
 
68gmsee's Avatar
 
Join Date: Jul 2007
Location: Centrally located between Houston, Austin and Waco. BCS area.
Posts: 7,947
Re: radiator question

Get a new cap and overflow tube or container. I'm using one on my old 68 GMC and did wonders to keep the coolant in the radiator and also helped keep it cooler. For some reason, it never did like being even a couple of inches low on coolant.

Here's my homemade one. (I've gone thru the rad support since this pic)
Attached Images
 
68gmsee is offline   Reply With Quote
Reply

Bookmarks


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 07:17 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com