Overheating issue

[litew8]

Originally Posted by 67 cst swb

You have the arrows running in the incorrect direction. Reverse the direction of the arrows.
The water pump... pumps water out of the engine into the radiator thru the bottom hose.
The water flows out of the radiator thru the top hose back into the engine.

Sure about that?

[seattle gmc]

Originally Posted by 67 cst swb

You have the arrows running in the incorrect direction. Reverse the direction of the arrows.
The water pump... pumps water out of the engine into the radiator thru the bottom hose.
The water flows out of the radiator thru the top hose back into the engine.

I disagree with your statment. My lower radiator hose has wire running through it to keep it from colapsing, from that "water sucker" pumping coolant through the engine.

[myyamr7]

Originally Posted by 67 cst swb

You have the arrows running in the incorrect direction. Reverse the direction of the arrows.
The water pump... pumps water out of the engine into the radiator thru the bottom hose.
The water flows out of the radiator thru the top hose back into the engine.

You're wrong! And it's simple to prove yourself wrong by removing your radiator cap, start the engine and let it warm up so the t-stat opens, and you will clearly see the direction of flow. As mentioned in this thread, there's a reason the lower hose has a coil wire inside it...and it's not there to add minerals to your coolant

[litew8]

The top hose should be empty when the thermostat is closed. When the thermostat OPENS, the pressure maintained/created by the water pump forces the heated coolant to pass by the thermostat (via engine) and enters into the radiator through the top hose -thereby causing the cooled coolant previously in the radiator to enter the engine via the bottom hose. When that cool coolant enters the engine, the thermostat recognizes and closes - allowing the newly heated coolant in the radiator to cool. Rinse, repeat.

[67 chevelle]

Picture is worth a thousand words , YOU NEED A SHROUD , will solve your problem

[67 cst swb]

That's it... I am calling my Dad...
I wonder what else he has taught me that is wrong... hahaha

myyamr7 & litew8... thank you for clarifying/correcting me... that makes perfect sense.

sjburk, sorry if I caused a lot of confusion.

[Ridgeclimber]

Originally Posted by 67 cst swb

You have the arrows running in the incorrect direction. Reverse the direction of the arrows.
The water pump... pumps water out of the engine into the radiator thru the bottom hose.
The water flows out of the radiator thru the top hose back into the engine.

This last quote is incorrect. The picture with the arrows was correct.

[Former member Yoder213]

Ive got similar problem, been told my alternator isn't providing enough power to my electric fan, and I don't have a shroud. new 4 core hoses, thermostats, caps,
only thing I haven't done is a heat gun. bout ready to let the shop tinker with it as I'm tired of driving with the heater on and its 115F out. (just got an original rear slider window, talk about a/c 8D )

[slikside]

Originally Posted by myyamr7

You're wrong! And it's simple to prove yourself wrong by removing your radiator cap, start the engine and let it warm up so the t-stat opens, and you will clearly see the direction of flow. As mentioned in this thread, there's a reason the lower hose has a coil wire inside it...and it's not there to add minerals to your coolant

You can also just put your hand on the upper hose when the thermostat opens. If the motor was cold when you first started it, you can actually feel the hot coolant running FROM the engine block through the upper hose and into the radiator.

[litew8]

Originally Posted by 67 chevelle

Picture is worth a thousand words , YOU NEED A SHROUD , will solve your problem

Not sure it's the root cause but should definitely help.

[litew8]

Originally Posted by Yoder213

Ive got similar problem, been told my alternator isn't providing enough power to my electric fan, and I don't have a shroud. new 4 core hoses, thermostats, caps,
only thing I haven't done is a heat gun. bout ready to let the shop tinker with it as I'm tired of driving with the heater on and its 115F out. (just got an original rear slider window, talk about a/c 8D )

Yeah, with electric fans you want to ensure you're providing an adequate supply to power (overall) - esp. if your adding electronics to a stock setup, when you do, you're using more resources essentially taking away from what is considered basic/needed. Shrouds were made for a reason Not sure your setup or if you need a shroud with your elec. fan setup, but for mechanical it's a given.

[imjeff]

Originally Posted by 67 cst swb

You have the arrows running in the incorrect direction. Reverse the direction of the arrows.
The water pump... pumps water out of the engine into the radiator thru the bottom hose.
The water flows out of the radiator thru the top hose back into the engine.

Nope. I'm pretty sure it's the other way. That's why there's a spring in the bottom (suction side). Hot water goes in the top and cooler pulled off the bottom.

Jeff

[71swb4x4]

The comment about the shroud is partly true, but a 6 cylinder shroud is almost more of a fan protector than a shroud, it's not going to help a lot. You can see the black shroud on top of the radiator in this picture.

[litew8]

Interesting

[litew8]

Originally Posted by 67 cst swb

That's it... I am calling my Dad...
I wonder what else he has taught me that is wrong... hahaha

myyamr7 & litew8... thank you for clarifying/correcting me... that makes perfect sense.

sjburk, sorry if I caused a lot of confusion.

If we can't laugh at ourselves, who can we laugh at. all good

[Curtm220]

I've had good luck in the past with drilling the t-stat base. 1/8 hole seems to allow the air to pass back the to radiator without allowing too much coolant to pass. . Any bigger than 1/8 I think would defeat the purpose of the t-stat.

[Togan66]

I had the same problem as described at the beginning of this thread on my '66 250 CID: first cycle of the thermostat would peg the gauge. It was very concerning. Replaced every thing multiple times, nothing fixed it. Even thought of air bubble/pocket. Nothing worked until I did exactly as Curtm220 mentioned..., 1/8 hole in base of thermostat. That was 6 years ago and never a problem again. BTW, 6 cylinders didn't come with a shroud - no such thing.

[litew8]

No such thing because they weren't invented yet? Or just because there isn't enough heat generated to justify the need?

[special-K]

Originally Posted by 67 chevelle

Picture is worth a thousand words , YOU NEED A SHROUD , will solve your problem

I doubt that,since all 67-72 L6s came from GM without a shroud.

[litew8]

Here's one on 60-66's, but he's got A/C and it's a 66. This is what I imagined it might look like, but I guess it was only for trucks (66 only?) equipped with a/c. Strange GM would eliminate the shroud, it looks dangerous without.

[litew8]

If the OP is still following along, I wonder if the problem is due to having replaced the thin two core radiator with a thicker 3 core radiator, and, not having a shroud.

[special-K]

Originally Posted by litew8

Strange GM would eliminate the shroud, it looks dangerous without.

There is a metal finger shield mounted

[sjburk]

Originally Posted by litew8

If the OP is still following along, I wonder if the problem is due to having replaced the thin two core radiator with a thicker 3 core radiator, and, not having a shroud.

I was also thinking it may have something to do with that, I still have my old radiator and ive been considering having it restored my grandfather says he knows a guy and he will ask soon. And about that drilling a hole in tstat, can i see a pic of exactly where you drilled the hole?

[Curtm220]

Originally Posted by sjburk

I was also thinking it may have something to do with that, I still have my old radiator and ive been considering having it restored my grandfather says he knows a guy and he will ask soon. And about that drilling a hole in tstat, can i see a pic of exactly where you drilled the hole?

Google "drilled thermostat" and look at the images tab. Many thermostats now come new with a relief machined into the base to remedy the exact problem you're describing.

[special-K]

Wholly thermostat Batman! I wonder why the L6s that never had the drilled thermostat never had this issue all those years