Big Block overheating - Chevelle Tech
Heating & Cooling Heating, cooling and air conditioning

 1Likes
Reply
 
LinkBack Thread Tools Search this Thread Display Modes
post #1 of 21 (permalink) Old Apr 3rd, 13, 4:28 PM Thread Starter
Tech Team
 
Join Date: Jun 2005
Location: Dallas
Posts: 54
Exclamation Big Block overheating

66 el camino, 454 with 400 turbo 3:73 diff, huge aluminum radiator, two electric 15" fans (don't move much air) and a high volume aluminum water pump, no thermostat, stock 1975 truck motor with aluminum intake.

Engine takes a while but overheats up to 230.

When I opened the hood to start working on it today after it sitting since yesterday, the upper hose was completely collasped, sucked flat.

I started up the engine and the pump is moving water and as I increase rpm the flow increases.

regular 50/50 water antifreeze ratio and water wetter.

I ran it twenty miles on the highway yesterday in 60 degree weather and by the end of the 20 miles it was at 230. Same thing on the way home. The fans shouldn't impact the cooling at highway speeds. I was driving 60-70.

It always overheats. Elky overheated with a monster 450 hp 427 before I changed it to this motor.

I ran this truck motor on an engine stand with its original rad and shroud and fan and it never overheated.

Help?
mikus517 is offline  
Sponsored Links
Advertisement
 
post #2 of 21 (permalink) Old Apr 3rd, 13, 6:15 PM
Tech Team
 
Join Date: Feb 2007
Location: Exton, Pa
Posts: 528
Re: Big Block overheating

The answer no one wants to hear. Stockity, Stock- Stock! Stock factory shroud, stock 7 blade fan with stock thermo-clutch and a 185 degree thermostat. The electric fans etc look sexy but as you have found out, hard to make them work right. I have a 454 4-Speed Monte with A/C. Totally stock cooling system in good condition. It will idle all day long in 95 degree weather with the A/C on and not overheat. Will run at 70 all day long with the A/C on and not overheat. Gm engineers knew what they were doing.
RichG is offline  
post #3 of 21 (permalink) Old Apr 3rd, 13, 7:06 PM
Tech Team
Mark
 
Join Date: Jun 2007
Location: Maryland's Eastern Shore, Cambridge MD.
Posts: 886
Re: Big Block overheating

I agree with us
Boo.Man.1971 is offline  
 
post #4 of 21 (permalink) Old Apr 3rd, 13, 7:20 PM
Tech Team
Mark
 
Join Date: Jun 2007
Location: Maryland's Eastern Shore, Cambridge MD.
Posts: 886
Re: Big Block overheating

I agree with using the stock shroud and heavy duty fan clutch , which was used with A/C cars . You may have lean condition with your fuel , this would also make the engine run warmer , if you can keep your temperature under 210 would be good for a big block. There are other things you can do, like run colder plugs and add more water to your coolant.
Boo.Man.1971 is offline  
post #5 of 21 (permalink) Old Apr 4th, 13, 12:00 AM Thread Starter
Tech Team
 
Join Date: Jun 2005
Location: Dallas
Posts: 54
Re: Big Block overheating

Thanks. I tend to agree with stock stock stock. It has no shroud and the fans are really weak. I'm going to check some other things. Radiator might be partially blocked. Water pump might not be pushing enough water, etc. but the bottom line is stock.
mikus517 is offline  
post #6 of 21 (permalink) Old Apr 4th, 13, 12:29 AM
Senior Tech Team
Jason
 
Join Date: Sep 2005
Location: Des Moines, IA
Posts: 1,173
Re: Big Block overheating

Quote:
Originally Posted by mikus517 View Post
Thanks. I tend to agree with stock stock stock. It has no shroud and the fans are really weak. I'm going to check some other things. Radiator might be partially blocked. Water pump might not be pushing enough water, etc. but the bottom line is stock.
So it's really not the fans after all...no shroud, weak fans and possibly a partially blocked radiator. What did you expect it to do??


Sent from AutoGuide.com App

_________________________
'70 Chevelle
Current build:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Blownchevelle68 is offline  
post #7 of 21 (permalink) Old Apr 4th, 13, 2:36 PM Thread Starter
Tech Team
 
Join Date: Jun 2005
Location: Dallas
Posts: 54
Re: Big Block overheating no more

Before ordering a correct radiator, shroud, and clutch fan, I went to Pep boys and bought one of those cut your finger off direct drive fans. Ripped the electric fans off. Installed fan, filled radiator, started car.

I let it run at idle in my driveway for an hour. Max 160 degrees.

I have some loose ends to secure before taking it out, but looking good.

Thanks again to everyone for their suggestions.
mikus517 is offline  
post #8 of 21 (permalink) Old Apr 4th, 13, 6:00 PM
Lifetime Premium Member
Bob
 
Join Date: Mar 2005
Location: Jeannette Pa. near pittsburgh
Posts: 8,817
Re: Big Block overheating

I drive a 70 SS 468 Sta. Wgn. with a 700R4-3:08 Rear gear. AND it has factory A/C.
Cooling system-- 100%--1970 to the last detail. ( 772 fan, Clutch , and shroud, 811TX water pump, copper four row rad, Or just like my one owner LS-5/ M-22 with A/C.
Car has over 35.000 miles city & Highway, NO cooling issues. Parked in the sun on a hot day with the A/C engaged, It never gets hot.
I still like the 43 year old ideas, WHY? = They Work.
Remember the stock 772 fan & Clutch NOT ONLY pull air through the heat exchanger they ALSO remove the super heated air from the engine compartment, VIA Exiting the air at the rear of the LEFT & RIGHT exhaust manifolds. Why does this system work?
When " ALL FACTORY ITEMS " are in place, It operates like your furnace, Big blower motor along with Duct work.
Just something to think about. Think a lot and be KOOL...........
Bob


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
1970 SS LS-5/M-22 El Camino- Org. Owner-AACA 2016-Senior Grand National Winner---MCACN-GOLD-2013
1970 ( FRAUD) SS 468 Station Wagon - Driver.
Robinls5 is offline  
post #9 of 21 (permalink) Old Apr 4th, 13, 6:13 PM
Tech Team
 
Join Date: Feb 2007
Location: Exton, Pa
Posts: 528
Re: Big Block overheating

Quote:
Originally Posted by Robinls5 View Post
I drive a 70 SS 468 Sta. Wgn. with a 700R4-3:08 Rear gear. AND it has factory A/C.
Cooling system-- 100%--1970 to the last detail. ( 772 fan, Clutch , and shroud, 811TX water pump, copper four row rad, Or just like my one owner LS-5/ M-22 with A/C.
Car has over 35.000 miles city & Highway, NO cooling issues. Parked in the sun on a hot day with the A/C engaged, It never gets hot.
I still like the 43 year old ideas, WHY? = They Work.
Remember the stock 772 fan & Clutch NOT ONLY pull air through the heat exchanger they ALSO remove the super heated air from the engine compartment, VIA Exiting the air at the rear of the LEFT & RIGHT exhaust manifolds. Why does this system work?
When " ALL FACTORY ITEMS " are in place, It operates like your furnace, Big blower motor along with Duct work.
Just something to think about. Think a lot and be KOOL...........
Bob
But it doesn't look as sexy as electric fans and no shroud......
(Sarcasm! Mine is all stock as well! GM knew what they were doing, they had to WARRANTY the car!)
RichG is offline  
post #10 of 21 (permalink) Old Apr 4th, 13, 7:14 PM Thread Starter
Tech Team
 
Join Date: Jun 2005
Location: Dallas
Posts: 54
Re: Big Block overheating

Yep! Agreed! I got the el camino as an ex drag car from California. Everything was cobbled together and I have been slowly, and happily, rectifying things one at a time, everything leaked. Was taped, zip tied together, with wires from who knows where and for what. Good news is it is rust free with a great body paint and interior. We'll get there!
mikus517 is offline  
post #11 of 21 (permalink) Old Apr 4th, 13, 7:15 PM Thread Starter
Tech Team
 
Join Date: Jun 2005
Location: Dallas
Posts: 54
Re: Big Block overheating

My bone stock 65ss Malibu has NO heating problems, period.
mikus517 is offline  
post #12 of 21 (permalink) Old Apr 4th, 13, 7:16 PM
Senior Tech Team
Keith
 
Join Date: Aug 2007
Location: The Sunny South
Posts: 2,293
Re: Big Block overheating

Put the correct, functional thermostat in your engine. Thermostats are not mistakes, restrictions or optional equipment. They are a critical and integral part of your cooling system design...Period.

Keith
CoolBlueGlow is offline  
post #13 of 21 (permalink) Old Apr 4th, 13, 8:25 PM
Senior Tech Team
Greg.
 
Join Date: Apr 2011
Location: Ottawa, On, Canada
Posts: 5,351
Garage
Re: Big Block overheating

Quote:
Originally Posted by mikus517 View Post
Engine takes a while but overheats up to 230.

When I opened the hood to start working on it today after it sitting since yesterday, the upper hose was completely collasped, sucked flat.
Why is the upper hose collasping ?

Is the water pump a reverse flow ??

I have a 2 row 1.5" sized tubes Alumitech rad on my car with dual 11" Spal fans shroud
that has the hwy flow through flaps with my 468 ci 525hp / 535 ftlbstorq TH400 trans and 3.55 rear gears
driven on the street/hwy & at the track when the weather is good, hot and humid

NO overheating problems .

67 Chevelle Malibu SS Cdn
Born 283 / PG / A51
468/TH400 2,500 stall/ S60 3.70 Gs
Prev Best on M/T ET S/S #3454 street Tires/Dress 2018/05/20
60' = 1.664
1/8 = 7.532 et / 91 mph
1/4 = 11.814 et / 115 mph
NEW Best with 3,500+ Stall TC 2019/09/08
60' = 1.547
1/8 = 7.311 et / 91.76 mph
1/4 = 11.595 et / 114.28 mph


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Kirk's67SS is offline  
post #14 of 21 (permalink) Old Apr 4th, 13, 8:35 PM
Senior Tech Team
Greg.
 
Join Date: Apr 2011
Location: Ottawa, On, Canada
Posts: 5,351
Garage
Re: Big Block overheating

Quote:
Originally Posted by CoolBlueGlow View Post
Put the correct, functional thermostat in your engine. Thermostats are not mistakes, restrictions or optional equipment. They are a critical and integral part of your cooling system design...Period.Keith

Disagree
as thermostats are only used to bring the engine upto a certain temp quicker
and to keep passengers warm in the winter!

I donot run a thermostat in my car, thus more flowing of the coolant is achieved .

The # 1 Rule according to experts is increased coolant flow ! See this site
http://www.arrowheadradiator.com/14_rules_for_improving_engine_cooling_system_capab ility_in_high-performance_automobiles.htm

I ran my 65 GTO in the 80s without a thermostat on the street and at the track
never ever overheated , or hurt it in any way .

67 Chevelle Malibu SS Cdn
Born 283 / PG / A51
468/TH400 2,500 stall/ S60 3.70 Gs
Prev Best on M/T ET S/S #3454 street Tires/Dress 2018/05/20
60' = 1.664
1/8 = 7.532 et / 91 mph
1/4 = 11.814 et / 115 mph
NEW Best with 3,500+ Stall TC 2019/09/08
60' = 1.547
1/8 = 7.311 et / 91.76 mph
1/4 = 11.595 et / 114.28 mph


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

Last edited by Kirk's67SS; Apr 4th, 13 at 9:00 PM.
Kirk's67SS is offline  
post #15 of 21 (permalink) Old Apr 4th, 13, 9:44 PM
Senior Tech Team
Jason
 
Join Date: Sep 2005
Location: Des Moines, IA
Posts: 1,173
Re: Big Block overheating

Quote:
Originally Posted by Kirk's67SS View Post
Why is the upper hose collasping ?

Is the water pump a reverse flow ??

I have a 2 row 1.5" sized tubes Alumitech rad on my car with dual 11" Spal fans shroud
that has the hwy flow through flaps with my 468 ci 525hp / 535 ftlbstorq TH400 trans and 3.55 rear gears
driven on the street/hwy & at the track when the weather is good, hot and humid

NO overheating problems .

I'm assuming it was low on coolant, then sucked the hose down.

Too many times I read the same story, that electric fans are junk and only factory is correct.

In this case you can't blame the fans. Partially obstructed radiator, no fan shroud, maybe even bad T-stat trumps all.

If electric fans are so bad then why do 90% of vehicles today have them?


Sent from AutoGuide.com App

_________________________
'70 Chevelle
Current build:
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Blownchevelle68 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Chevelle 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, you will be sent a confirmation request to this address.

Email Address:
OR

Log-in









Old Thread Warning
This Thread is more than 2637 days old. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
If you still feel it is necessary to make a new reply, you can still do so though.

Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search
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