Team Camaro Tech banner

1 - 20 of 32 Posts

·
Registered
Joined
·
25 Posts
Discussion Starter #1 (Edited)
I just bought a 1968 Camaro RS with a 350 engine. When I bought it I was told that it has issues with overheating on warm days. I believe the radiator id copper and I'm running the six blade mechanical fan with a shroud. I want to increase the airflow, even at highway speeds, with minimal investment since I spent all of my $$$ on the car.

Can I just add a pusher fan, or 2, in front of the radiator and run both the pusher & the mechanical or do they counteract each other at high or low speeds?

Should I ditch the mechanical and just add an electric fan? Do I have to change to an aluminum radiator?

Any suggestions for a reasonably priced setup?

Any help is much appreciated...Thanks!
 

·
Registered
Joined
·
226 Posts
If radiator is original it probably need a recore job or replacement. It might not leak or have any other issues but if the cores are seperated from the fins in several places that would cause overheating. What about thermostat? Had it checked lately? you could go from a 180 degree to a 170 or 160 unit.
 

·
Premium Member
Joined
·
3,123 Posts
If your car is overheating while driving it down the highway, a pusher fan is not going to resolve your issue. You need to find out what's causing your issue.
Have you checked the thermostat to make sure it's opening and at what temp?
What's the timing set to (initial vs full) ?
What water pump are you running and what's the condition of it?
How far are the fan blades inside the shroud?
When it does get hot, how hot?
Where is the temp sending unit mounted?
 

·
Registered
Joined
·
25 Posts
Discussion Starter #4
Radiator is actually fairly new and in pretty good shape. I am seeing some corrosion in it so there might be a blockage. I'm going to try and flush the system. Not sure about the thermostat but i think it is okay. I was told that the RS's were notorious for overheating because of the hideaway headlights causing a lack of airflow. I wanted to see if there was a way to increase airflow for cheap. Was also considering removing the mechanical fan and installing an electrical one w a shroud. (Black Majic or something similar)
 

·
Registered
Joined
·
25 Posts
Discussion Starter #5
All good questions but I'm not sure I can answer them all. I guess it's a little more complicated that I had hoped.

The fan blades, on top, are about 1/2 in the shroud and 1/2 out. At the bottom, the fan blades are completely inside the shroud but just barely. Where should they be?

I think the water pump is new, but I'm not sure which one it is. I was on the freeway coming home and when I stopped for gas I was spewing fluid everywhere. Guess it hit 215 degrees. After the air temp cooled down I stayed below 190.

I just got the car a week ago. I can call the previous owner and prob find a few of those things out.
 

·
Registered
Joined
·
13,337 Posts
It is not an air flow issue if its over heating on the road
A lower temp thermostat will not change anything except how fast the engine warms up...unless it is the wrong spec for the engine (flow spec.)
The cooling systems are far to over built on these cars for timing way off to have any significant effect....modern cars yes it has a huge effect because the cooling system is designed to be only just large enough when the engine is in tune

There are many older threads coving what to do and how
1/ Back flush the radiator and pull the stop **** and see if any crap inside
2/Check or replace the cap
3/Check..well its out, they are cheap..replace the thermostat...with a 180 and make sure it meets 67 to 73 sb specs.....also check before putting in
4/Check radiator for blocked cores...1st start of the day feel for cold spots as it warms up...If blocked cores, get it manually cleaned
5/Check bottom hose still has the renforcing spring in it.
6/Get a HC check on the radiator...(Very cheap, generally free)...checking for a very clean spark plug indicates blown head gasket also.
 

·
Registered
Joined
·
8,303 Posts
I was told that the RS's were notorious for overheating because of the hideaway headlights causing a lack of airflow.
Complete and total BS, just so you know. If the same person told you the radiator was "pretty new", I would consider that potentially BS as well.

Also, FWIW, do you know that your car has an "open" cooling system (unless it has been modified)?? Unlike a newer car, with an overflow bottle which can catch fluid as the system heats up and return it to the radiator when things cool off, your new toy has a fluid level which should be several inches below the top of the cap neck when cold. Some radiators have a "full cold" type of marking on them, but sometimes you just have trial and error until it quits puking fluid out at operating temp. So if someone fills it full to the neck when cold, it will certainly puke fluid until it drops the level enough.

Also, would need to know more about temps under iddferent conditions/loads. I really don't think the temp spiking to 215 stopped after running on the freeway in So Cal in July is bad at all.
 

·
Gold Lifetime Member
Joined
·
3,193 Posts
Also, FWIW, do you know that your car has an "open" cooling system (unless it has been modified)?? Unlike a newer car, with an overflow bottle which can catch fluid as the system heats up and return it to the radiator when things cool off, your new toy has a fluid level which should be several inches below the top of the cap neck when cold. Some radiators have a "full cold" type of marking on them, but sometimes you just have trial and error until it quits puking fluid out at operating temp. So if someone fills it full to the neck when cold, it will certainly puke fluid until it drops the level enough.
Good call Eric, could be that he "keeps topping it off" and it keeps puking back to its happy level.. Might be no issue at all.
 

·
Registered
Joined
·
1,748 Posts
To add to what Eric and Bill have said, my 68 RS runs at a nice cool 175-180 all the time so the hideaway headlights have nothing to do with your issue. You have a 350 motor, any clue what's been done to it ? High compression motors build more heat. Headers help to shed some along with adding HP. High volume water pumps are a must on really pumped small blocks.

I'd flush the radiator, replace the t-stat with a 160F, and new coolant and see what happens.
 

·
Registered
Joined
·
25 Posts
Discussion Starter #12 (Edited)
Interesting! That very well may be the case. I was looking for an overflow only to find out that they dont make them for the 68 so that makes sense.

The engine #'s dont match so this engine is newer than the original. Will that make a difference with the open cooling system? If I add an overflow & essentially close the system can that cause any damage?

I'm noticing what appears to be rust in the fluid because he was running only water and it is exposed to the air due to the open system so I plan to flush everything anyway.

Thanks for all of your help everyone. This is my first classic car and I've only driven it home so far. I guess it is all a learning process!
 

·
Premium Member
Joined
·
3,578 Posts
If it is over heating on the highway the lower radiator hose is collapsing at speed.
 

·
Premium Member
Joined
·
1,213 Posts
I wouldn't say that timing specifically has anything to do with it, but I would check out the full manifold vacuum setup JohnZ describes on CRG. Made all my distributor cars run great and cool.
 

·
Gold Lifetime Member
Joined
·
3,193 Posts
Easy test for the bottom hose is to try to squeeze it in the center with the cap off. If it collapses replace it and go from there. Be sure to use a hose with the spring inside of it
 

·
Registered
Joined
·
1,748 Posts
If it is the lower hose, take the old one with you when you get a replacement. I have an 89 block with a long water pump and a 4 core radiator so the hose listed in the parts books doesn't work. I use a NAPA #7400 and have to trim ~1.5" off it.

Aren't these contraptions fun :)
 

·
Registered
Joined
·
13,337 Posts
replace the t-stat with a 160F, and new coolant and see what happens.
Didnt you read the post ablove...the thermostat all it does is warm the engine up quick to the operating temp fast.
This is to bring the engine oil temp, toleraces etc up to the correct operating temp..less engine wear on starts and warm up and running
The spec for chev sb is 180 deg...If you are running specialist fuels like LPG 140 or 160

The thermostat, unless it is is faulty, has nothing to do with over heating.

Next thing you know some bright spark will come up and suggest colder spark plugs make it run colder.
 

·
Banned
Joined
·
3,193 Posts
Interesting! If I add an overflow & essentially close the system can that cause any damage?
I'm noticing what appears to be rust in the fluid because he was running only water and it is exposed to the air due to the open system so I plan to flush everything anyway.
An open system will have an air pocket at the top of the radiator.
Adding an overflow bottle gives the fluid a place to expand to when it heats up. When it cools, it draws the fluid back into the radiator and eliminates the air pocket that would be there otherwise. It's just a better way to do things and won't hurt your system in any way; it will help with cooling and slow down corrosion.
 

·
Registered
Joined
·
42 Posts
A thermostat can absolutley cause overheating. If the thermostat is too cool it will not close. Therefore it will keep circulating the fluid constantly getting it hotter and hotter. It will never allow it to be trapped in the radiator to cool it down. Sounds strange but sometimes you have to run hotter termostat to keep it cool. Particularly on modified engines. Seen it time and time again with the local kids who haven't built up the experience yet for the ins and outs. But that's OK because that's what this website is for.

Unless your motor is wildly built. I would:
Check radiator and flush. Depending on what comes out, this might be your only step.
Check radiator hoses. Replace as needed.
Replace the thermostat. For the cost of thermostat and gasket, just replace it.
Make sure antifeeze is good.
Check and adjust timing if needed.

Start there and see what happens.
 

·
Registered
Joined
·
25 Posts
Discussion Starter #20
Perfect! Thats sort of what I though. I found a pretty cool stainless overflow so I'll probably just do that. Thanks for your help
 
1 - 20 of 32 Posts
Top