Mr. Wonderful

I recently purchased a 69 small block 4 speed, and find the anti-freeze coming out of the overflow tube in the expansion tank. I noticed a small puddle of fluid on my garage floor and it's directly beneath the tube from the tank.
Is it possible this is being caused by the wrong radiator cap on the expansion tank ? If so, how many pound pressure is recommended (15 ?). Any other possible causes ? :confused: Thanks

lbell101

Mine used to do that too. I'm sure there are many possible reasons. Mine turned out to be the fact that Bubba decided to leave out the thermostat. It would also get hot at consistantly high speeds (75 -80 mph). Put one in and the puddle and hot running is gone.

Larry B.

I have a 69BB that did that. Mine was caused by a generic flex upper radiator hose that put the high point of the system at the hose instead of at the cap. Air goes to the highest point of the system and forces water out as it expands. A correct formed upper hose fixed my problem. :)


[Modified by silvervetteman, 5:16 PM 1/2/2002]

PRNDL

hmmm... if you have the expansion tank, then your radiator has no cap, right? I ask this question because it is very easy to overfill the radiator, and your car will puke out any excess plus more if it is overfilled. I am not sure how you correctly fill a system that is filled from the expansion tank only.

A small amount of overflow may be considered normal. My 68 has an overflow hose that goes straight to the ground (street, driveway, garage... whatever!). I used to fret, worry, and get very upset about overflow, puking, peeing, whatever you want to call it, especially in the garage!! My solution was to install a plastic aftermarket overflow tank. Now, in hot weather I may get a pint of coolant in the tank, and it gets sucked back into the radiator after the engine cools off. No mess in the driveway, end of problem. MJ

Mr. Wonderful

MNJack wrote: if you have the expansion tank, then your radiator has no cap, right?
My radiator DOES have a cap ! One on radiator and one on expansion tank.
Is this incorrect ?
I like your idea of the plastic overflow tank.... may go that route if I can't solve my problem.
Thanks

Paul L

Do not have the answer to the question but...you have my dream car. Very nice!

yellow 72

Check your coolant level when cold, expansion tank should be half(or a little less)full.
I would buy a good quality cap(stant) of around 10-13 lbs. and everything should be right with the world :cheers:
Under normal conditions the expansion tank shouldn't :U

Larry B.

You are right !.... If you fill the tank to the top when the engine is cold, the first time you get it to normal temperature, the excess water will vent out and from then on it will be OK. (unless you re-fill it)

Mr. Wonderful

When cold, I topped off the radiator, and filled expansion tank 1/2 way. I drove about an hour. When I parked it, the next day I noticed the puddle under the expansion tank overflow hose on my garage floor. I am going to check to see if car has a thermostat as lbell101 suggested. If that isn't the answer, I will try yellow 72's idea of the new radiator cap.
Thanks all. I will post any findings.

rdrman

Last year I had a probkem with the overflow tank. Except the radiator level was going down all the time. To make a long story short,it turned out to be the overflow hose it self!! When the car vented to the overflow tank there was a pin hole in the hose,thus the puddle on the floor.Once it cooled off and tried to pull the coolent back into the radiator the pin hole would not allow a siphon action and allowed air to be pulled into the radiator rather than coolant. So I had the puddle plus the radiator level and tank level kept dropping in unison.The lower the Radiator level went resulted in MORE air being pulled into the system,found this after replacing all the normal items such as the cap, themostat,and hoses...that little hose Is important!Never did find the hole in it but once replaced all the problems went away at once,and easy and cheap fix :cheers:

Rowdy Rat

There should only be one cap regardless of the application. I'm quite sure that this is at least part of your problem.

For a 1969 small block, the cap will be either be an RC-15 (rated at 15#) which is used on cars with copper radiators (without expansion tanks) or those equipped with brass expansion tanks. An RC-26 (also rated at 15#) is used on cars equipped with an aluminum expansion tank. Both caps are still available from GM, although there are some differences in appearance that distinguish them from the originals.

Which engine/transmission was originally installed in your car (and does it have air conditioning)... This should allow us to identify what was in the car originally (my guess is that your car should have an aluminum radiator).

Regards,


[Modified by Rowdy Rat, 8:45 AM 1/5/2002]

Mr. Wonderful

After checking, I have found that I have an RC-15 cap on the radiator, and an RC-27 cap on the expansion tank, both 15 lbs.
I have also checked and found car does not have a thermostat. Could this be causing my problem ? What degree stat would be best for my South Florida car (no A/C). Thanks


[Modified by FathomGreen69, 1:00 PM 1/9/2002]

SevenT1Shark

I could not help it , i just have to say nice car and nice color. Gotta love them greens. :seeya :cheers: :D :D :D