68 327 - new radiator, still running hot - Team Camaro Tech
Heating & Cooling Heating, cooling and air conditioning

 14Likes
Reply
 
LinkBack Thread Tools Display Modes
post #1 of 46 (permalink) Old Jun 12th, 17, 11:21 AM Thread Starter
Tech Team
Dusty
 
Join Date: May 2016
Location: Seattle Washington
Posts: 30
68 327 - new radiator, still running hot

Hey all- having some cooling issues with my 68 327 that I was hoping to get sorted out this week. In the past, it's ran really hot and I haven't been able to drive it far before the temp gauge gets up toward the high end of the gauge. (stock temp gauge so not sure what the actual temperature is)

I took the radiator out and took it to a shop where it was flow tested and determined to be about 40% plugged and generally toast. I had a quality new one ordered from the radiator shop and installed myself last week. In addition, I added a flex fan and a proper 2" spacer since the old one wasn't even sitting inside the fan shroud. I also swapped out the thermostat for a new one as well (functioning). Filled up with coolant and let her idle for about 10min and then topped it off.

The problem is, I'm still getting the heat issue when driving.

Heater blows warm air, radiator hoses don't seem too hot at all (can touch the top one bare handed easily). Lower rad hose is cool to the touch. Coolant level drops when car is warmed up. I'm not convinced it's actually running hot to be honest, but I'm not sure.

What would be your next move? Water pump? Temp Sender? I'm fairly new to this car so I've not much experience troubleshooting small blocks at all. Was hoping for some help as to what this could be.

Thanks!!
Dusty Diamond is offline  
Sponsored Links
Advertisement
 
post #2 of 46 (permalink) Old Jun 12th, 17, 11:37 AM
Moderator
John
 
Vega$69's Avatar
 
Join Date: Sep 2010
Location: Vegas NV/Wesley Chapel FL
Posts: 13,279
Garage
Re: 68 327 - new radiator, still running hot

Do you have a shroud around the fan?

1st thing is to get an accurate gauge reading

2017 Corvette ZO6 with ZO7 Option
66 Chevelle Protour LS3/525(SOLD AT Mecum 2018)
69 SS396 Cortez Silver(SOLD)
69 Z28(Sold)
69 Pro Tour - LS3/T56
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
(SOLD)
69 Pro Tour - LS7/T56 (SOLD)
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

69 Z28/RS Tribute355/5 Speed (SOLD)
69 RS Clone 427/TH400 (SOLD)
67 RSZZ502/5 Speed (SOLD)
69 Camaro 406 SBC/TH400 (SOLD)
Vega$69 is offline  
post #3 of 46 (permalink) Old Jun 12th, 17, 11:51 AM Thread Starter
Tech Team
Dusty
 
Join Date: May 2016
Location: Seattle Washington
Posts: 30
Re: 68 327 - new radiator, still running hot

Yes, there's a large plastic shroud around the fan, joined to the radiator, and the fan sits approx 3/4" deep into that shroud. Looking into an accurate temp reading gauge now.
Dusty Diamond is offline  
 
post #4 of 46 (permalink) Old Jun 12th, 17, 11:59 AM Thread Starter
Tech Team
Dusty
 
Join Date: May 2016
Location: Seattle Washington
Posts: 30
Re: 68 327 - new radiator, still running hot

This might be a stupid question, but what's the best method of testing that temperature gauge and/or replacing it with one that measure exact temperatures?

I'm trying to avoid just buying another sender if it's not the issue to begin with.
Dusty Diamond is offline  
post #5 of 46 (permalink) Old Jun 12th, 17, 12:35 PM
Senior Tech
Dave
 
Join Date: Dec 2005
Location: Tampa, Florida
Posts: 4,749
Re: 68 327 - new radiator, still running hot

First thing as John mentioned is to identify your problem. You may have a broken temp gauge.

I personally prefer a mechanical temperature gauge (the one with the long spring steel cable and a bulb filled with mercury). With the power off it still reads the correct temp, so if you are overheating and stranded on the side of the road you can keep tabs on the coolant temp.

Second is my preference for a broad bladed fan (with the more blades the merrier), but coupled with a thermostatic viscous fan clutch that only locks up when the air coming off the radiator is hot. You are not saving any energy with a flex fan. It takes energy to straighten out those fan blades that the manufacture says saves you horsepower. As your grand father could have told you there is no free lunch. A fan clutch not only saves you energy but prevents the fan from spinning up in excess of it's intended operating RPM.

Fans will cavitate if spun too fast or shed a blade or three as happened with this flex fan in a Team Nova's SBC 406:



The other item in your cooling system is the water pump. Keep in mind that GM is interested in making money. To that end the car is designed very intentionally to be made as cheaply as possible. Your water pump has a Robert Fulton inspired paddle wheel moving water inside of it.

If you have ever ridden on a steam boat from the mid eighteen thirties you have no doubt gone astern to look at the paddle wheel beat the water to foam. Robert Fulton did a great job of installing a boiler and a steam engine on a boat that allowed it to go up stream or move against tide and light winds. John Ericsson (the marine architect who built the Monitor for civil war naval battle against wooden sailing ships also invented the "steam screw" or propeller used on all ships today (except at Disney World and excursion cruises on the Mississippi).



Aftermarket water pumps are not only made of aluminum to save six pounds off the front end, but had an enclosed impeller instead of a paddle wheel. Higher priced racing water pumps have a CNC machined scroll impeller as found inside a water well pump to move a lot more water with less effort.

Stewart sells a Phase Three and Four water pump that moves twice the volume of water with half of the effort (parasitic horsepower drain). Some people find aluminum offensive and abhor it's use on their ideal Camaro, but I would point out Chevy Orange engine paint sticks to aluminum just as well as cast iron. I have fooled a lot of people on the side of the road late on a Friday night with Big Chief heads painted Chevy orange.

Going back to your radiator it requires air to actually go through it not around it. If you have gaping holes in your core support or have the grill stuffed with transmission oil coolers and air conditioning condensers you may need an air dam as found on modern cars to prevent air from by-passing the radiator altogether. The air dam increases the air pressure built up in front of the radiator to push air through the core.




To test a gauge you put it in a pot of boiling water. It should read 212 degrees at sea level, less for higher altitudes. I compare mine to the readings of a Candy Thermometer that is accurate to a half of one degree in the same pot of boiling water.

Big Dave
zdld17 likes this.
Larger Dave is offline  
post #6 of 46 (permalink) Old Jun 12th, 17, 11:11 PM Thread Starter
Tech Team
Dusty
 
Join Date: May 2016
Location: Seattle Washington
Posts: 30
Re: 68 327 - new radiator, still running hot

Wow, Big Dave- a lot of great info there! It all makes sense to me, I'm just trying to work with what I've got if at all possible, but if it comes down to the water pump needing to be replaced, or the fan not being sufficient, I won't hesitate to upgrade to more modern tech.

So here's where I'm at now- I started the car back up and added some more coolant bringing it up to about 3" below the filler cap. Cranked up the heater (blows hot) and let it idle for about 15-20 minutes, hoping to get rid of any possible air in the system. The temp gauge reads dead center between H/C. I took it for a spin around town and the temp goes up, as before. It's not getting to a crazy high temp during normal street driving, but if I hit some traffic I'm afraid it would overheat. I live in Seattle area, so that's a definite possibility. Below is a photo of the 'normal' operating temp when driving around neighborhoods at about 30-45mph on a 65 degree day.


I don't know what the actual degrees are in the engine as I only have the stock H/C gauge. I did check to see if the sender was recieving power with a test light and then grounded the wire to check that the gauge in the dash would react, and it did as expected, so I know the gauge itself works, but I'm not sure if the sender is faulty or not.

I'm also attaching a photo of the fan/radiator assembly I have going. Seems like it should do the trick, but I'm a novice when it comes to this car.

Dusty Diamond is offline  
post #7 of 46 (permalink) Old Jun 13th, 17, 03:41 AM
Senior Tech
Scott
 
Join Date: Aug 2008
Location: CT
Posts: 7,380
Re: 68 327 - new radiator, still running hot

You do not need to upgrade to more modern tech as you suggest. A stock GM cooling system will cool your engine quite efficiently. Buy a clutch fan and scrap that flex fan. Make sure you have flow and the radiator hose is not collapsed. Buy an IR gun (infrared thermometer). Or throw on another temp gauge if you have one laying around. Find out what the actual temperature is before you start guessing and tossing parts at the car. Was that radiator you replaced a Harrison? If so you could have had it re-cored if original tanks were of importance. Many radiator shops have no knowledge of value and will scrap a valuable radiator.
69-Pace likes this.

Call for restoration and custom paint scheduling:
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Sauron67MM is offline  
post #8 of 46 (permalink) Old Jun 13th, 17, 06:00 AM
Moderator
John
 
Vega$69's Avatar
 
Join Date: Sep 2010
Location: Vegas NV/Wesley Chapel FL
Posts: 13,279
Garage
Re: 68 327 - new radiator, still running hot

It appears from the pictures the fan is not deep enough in the shroud.

How far is the fan from the radiator?

The gauge seems to be working however the H/C gauge does not show temp. I've seen these gauges different car with the needles all over the scale at the same engine temp. So using another gauge or IR gun to determine actual temp so you know where you're at.

In any event I would definitely ditch the flex fan and install an OEM style clutch fan.
69-Pace likes this.

2017 Corvette ZO6 with ZO7 Option
66 Chevelle Protour LS3/525(SOLD AT Mecum 2018)
69 SS396 Cortez Silver(SOLD)
69 Z28(Sold)
69 Pro Tour - LS3/T56
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
(SOLD)
69 Pro Tour - LS7/T56 (SOLD)
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

69 Z28/RS Tribute355/5 Speed (SOLD)
69 RS Clone 427/TH400 (SOLD)
67 RSZZ502/5 Speed (SOLD)
69 Camaro 406 SBC/TH400 (SOLD)
Vega$69 is offline  
post #9 of 46 (permalink) Old Jun 13th, 17, 09:17 AM
Senior Tech
kevin
 
Join Date: Mar 2012
Location: virginia
Posts: 3,857
Re: 68 327 - new radiator, still running hot

with due respect to the other posts. I been using flex fans since I bought my 68 Camaro in 72. the first was a fiberglass and I can tell you it made many a trip down the 1/4 mile and seen many a red line on the street. I still have it and is still intact. although I don't use it any more.
I now use the derale 6 blade HD flex stainless fan that has been on the car for 5 years and also has seen 7 K many times
this one is rated to 10K rpm
the leading edge of the fan sets in 3" from the shroud and 3" from the radiator. running an aluminum water pump and I almost never see 180* and that is in parade traffic. it normally runs 165-170*
as stated above the air needs to go through the radiator, not around it.
it may help you if you get or make a filler panel to enclose the top and bottom of the radiator
here is a picture of the bottom panel

here is a picture of the top I made

with these 2 panels it really funnels the air through the radiator
yep there will someone say that my engine is running to cold
.
I have never heard of a head gasket blowing because of being to cold, to hot DAMN STRAIGHT
flat tire is offline  
post #10 of 46 (permalink) Old Jun 13th, 17, 10:46 AM
Moderator
John
 
Vega$69's Avatar
 
Join Date: Sep 2010
Location: Vegas NV/Wesley Chapel FL
Posts: 13,279
Garage
Re: 68 327 - new radiator, still running hot

Quote:
Originally Posted by flat tire View Post
.
I have never heard of a head gasket blowing because of being to cold, to hot DAMN STRAIGHT
Even if you put 5000 cfm of 20* air thru the radiator the engine would never run colder than the T-stat rated temp once the engine is warmed up.
Vega$69 is offline  
post #11 of 46 (permalink) Old Jun 13th, 17, 10:49 AM Thread Starter
Tech Team
Dusty
 
Join Date: May 2016
Location: Seattle Washington
Posts: 30
Re: 68 327 - new radiator, still running hot

I'm going to go snag an IR gun today so I can get more accurate readings on the engine temp moving forward.

A little background on the radiator. I took the stock Harrison into a radiator shop and consulted with the owner there who is the original owner of a cherry 67 camaro drag car. He advised me on the cost of rebuilding the stock vs. getting a quality 3 core replacement (one that he personally recommended). I went with the replacement, but kept the original just in case I wanted to do something in the future.

The fan he advised, should sit about 3/4" inside the shroud. I'm running a 2" spacer to achieve this. Not sure if you can go longer than that.

Based on the above, is the concensus that I need to go with a clutch type fan and possibly look into airflow issues?

I'm just trying to make sure that I'm not overlooking some boneheaded major part of the cooling system, (ie. water pump, air in the system, fan on backwards... etc)
Dusty Diamond is offline  
post #12 of 46 (permalink) Old Jun 13th, 17, 11:12 AM
Senior Tech
Dave
 
Join Date: Dec 2005
Location: Tampa, Florida
Posts: 4,749
Re: 68 327 - new radiator, still running hot

Hot and cold are determined by the need to protect the motor oil. Too cold and it is closer to grease than oil if you are running a high viscosity number. Too hot and the oil oxidizes rapidly filling the engine with ash that scours the bearings.

The motor is running at 1,560 degrees above the piston so ten or twenty degrees more or less is not nearly as important to the engine as it is to the oil.

Combustion chamber temperature varies by fuel type and amount of oxygen available for oxidizing the fuel. You have to build the engine to match that combustion chamber heat in piston to cylinder clearance and ring end gap, but once again twenty degrees isn't going to be critical if you built in the correct clearances.

Another way of protecting the motor oil from excessive engine temps is an engine oil cooler (included on all of older V8 Caprice cop cars and light trucks with a towing package if you want to find one in the bone yard). It will protect and extend the life of your oil's service life.

Though not available back in the days when these cars were new running a lighter weight oil allows you to drop the motors temp operating temperature, while maintaing proper lubrication. Lighter weight oil also saves horsepower as it takes a lot of power to presurize motor oil to flow through the motor. The cooler the motor runs the more power you will make (it is the difference between peak temperature and heat sink temperature that makes the power you seek).



The further apart you can push the two sloping curved lines the greater the power available to do mechanical work.

One way of raising the temp is a power adder such as $5,000 Roots blower, or a $9,000 turbo charger or a $1,500 NOS plate kit. A bigger radiator to drop the bottom line is a Loooooooooooot cheaper. I might add that motor oil serves two functions: it lubricates moving parts as you are probably aware, and it cools the pistons and the valve springs (which is how it picks up heat in the engine, well above the coolant temp).

Big Dave
Larger Dave is offline  
post #13 of 46 (permalink) Old Jun 13th, 17, 11:29 AM
Senior Tech
kevin
 
Join Date: Mar 2012
Location: virginia
Posts: 3,857
Re: 68 327 - new radiator, still running hot

Quote:
Originally Posted by Vega$69 View Post
Even if you put 5000 cfm of 20* air thru the radiator the engine would never run colder than the T-stat rated temp once the engine is warmed up.
no but a carburetor might freeze up
I didn't dispute that. your point?
I stated my engine runs at 165-170* and have been told it is running to cold
my engine will not blow a head gasket at that temperature
flat tire is offline  
post #14 of 46 (permalink) Old Jun 13th, 17, 11:40 AM
Moderator
John
 
Vega$69's Avatar
 
Join Date: Sep 2010
Location: Vegas NV/Wesley Chapel FL
Posts: 13,279
Garage
Re: 68 327 - new radiator, still running hot

Quote:
Originally Posted by flat tire View Post
no but a carburetor might freeze up
I didn't dispute that. your point?
I stated my engine runs at 165-170* and have been told it is running to cold
my engine will not blow a head gasket at that temperature
IMHO 165*-170* it not warm enough for the moisture purged via heat and the PCV system.

My point was only that the engine will not run cooler then the T-stat will allow. I can run hooter but not cooler.

I only mention this because some people think if they have a 180* stat and their car runs hot that installing a 160* will make it run cooler. Which it won't
Vega$69 is offline  
post #15 of 46 (permalink) Old Jun 13th, 17, 11:42 AM
Senior Tech
Scott
 
Join Date: Aug 2008
Location: CT
Posts: 7,380
Re: 68 327 - new radiator, still running hot

Quote:
Originally Posted by Dusty Diamond View Post
I'm going to go snag an IR gun today so I can get more accurate readings on the engine temp moving forward.

A little background on the radiator. I took the stock Harrison into a radiator shop and consulted with the owner there who is the original owner of a cherry 67 camaro drag car. He advised me on the cost of rebuilding the stock vs. getting a quality 3 core replacement (one that he personally recommended). I went with the replacement, but kept the original just in case I wanted to do something in the future.

The fan he advised, should sit about 3/4" inside the shroud. I'm running a 2" spacer to achieve this. Not sure if you can go longer than that.

Based on the above, is the concensus that I need to go with a clutch type fan and possibly look into airflow issues?

I'm just trying to make sure that I'm not overlooking some boneheaded major part of the cooling system, (ie. water pump, air in the system, fan on backwards... etc)
Fan should be half in half out. Read this by John Hinckley: http://www.camaros.org/pdf/corv_cooling2.pdf It is well written will address all your cooling info.
I have a 327/300 with a 3 row radiator, stock cooling system and a clutch fan, no added gimmicks, and I don't run hot. My BB Chevelle is stock and does not overheat either. A friend with over 30 cars in his corral utilizes stock systems and he has no issues. Same with countless other people with stock systems.

Call for restoration and custom paint scheduling:
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Sauron67MM is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may 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
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome