Author Topic: 1969 Camaro Over Heating issue  (Read 1888 times)

camaroman1969

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1969 Camaro Over Heating issue
« on: July 08, 2017, 01:24:41 AM »
Hi Guys!!  Need some direction on a 69 Camaro BB that is over-heating bad.  I found the clutch fan touching back of radiator.  Corrected this, but still is HOT. Have flow in tank that was changed out during resto.  Suspect water pump may be culprit.  What is the best way to trouble shoot this issue???  All responses would be appreciated.  Thanks!   Don

dutch

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Re: 1969 Camaro Over Heating issue
« Reply #1 on: July 08, 2017, 01:36:16 AM »
Will not correct it - but get an infrared heat gun to figure out just how hot it really is first!

ssl78

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Re: 1969 Camaro Over Heating issue
« Reply #2 on: July 08, 2017, 02:29:57 AM »
Does it overheat when idling or cruising.

77thor

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Re: 1969 Camaro Over Heating issue
« Reply #3 on: July 08, 2017, 01:35:37 PM »
I would start with the thermostat...
1969 Camaro SS, 350(NOM), M21, 12 Bolt Posi, 01B LOS Build
1977 Camaro, 350(LM1), M20, 10 Bolt Posi, Purchased New, (SOLD)

WorkinProgress

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Re: 1969 Camaro Over Heating issue
« Reply #4 on: July 08, 2017, 05:58:20 PM »
Is there a fan shroud in place?

                             - Warren

camaroman1969

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Re: 1969 Camaro Over Heating issue
« Reply #5 on: July 09, 2017, 01:20:28 AM »
To All....We used unfared heat gun...185-190 going in and coming out.  Orginal fan shroud in place.  Changed thermostat to a high flow one from Jegs (high perf) still no good.  Added additive to coolant to disapat some heat, no good.  removed thermostat, and still no good.  Over heats driving and idling.  We think radiator has something wrong inside.  I think with this major problem, a Harrison tank should be installed.  These repo's don't preform at all.    Additional advice welcome.  Thanks guys

Stingr69

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Re: 1969 Camaro Over Heating issue
« Reply #6 on: July 09, 2017, 02:13:07 PM »
water pump impeller fell off?  you need to verify water flow. cold start car and leave cap off radiator.  watch for flow.  feel hoses to see if you have one hotter than the other.

bertfam

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Re: 1969 Camaro Over Heating issue
« Reply #7 on: July 09, 2017, 03:43:05 PM »
Quote
To All....We used unfared heat gun...185-190 going in and coming out.

185-190 is NOT overheating! In fact, the standard thermostat installed on these cars was rated at 195 degrees.

When you get to 220-230, then you're starting to get hot, but you're still not overheating. GM states in the Corvette owners manual that "Temperature gauge readings will vary with air temperature and operating conditions. During normal operation, gauge will indicate around the 210 degree mark. Hard driving, heavy traffic with stop and go, or prolonged idling in hot weather will produce a gauge reading around the 230 degree mark. Whenever the gauge reaches 250 degrees, stop engine and determine cause of overheating, or reduce speed permitting engine to cool".

This 250 degree limit applies to ALL Chevrolet engines produced in the late 1960's because they run hotter than the earlier engines. This is due to an early engineering attempt to reduce hydrocarbons, oxides of nitrogen and other byproducts of internal combustion engines (pollutants), to meet EPA requirements. Before the late 1960's, distributor vacuum advance canisters were connected to full manifold vacuum. When the vacuum advance was changed to ported vacuum, this caused the engine to run hotter, thereby burning off the excess pollutants. Well, kind of! It was a band-aid fix at best and really didn't do too much in the way of reducing pollution. But it satisfied the EPA to a certain extent until better methods (like the catalytic converter) was introduced.

If you want to put the vacuum advance BACK to full manifold vacuum (and yes, this will help with overheating), follow John's instructions in THIS THREAD. However, like I stated in my first sentence, 180-190 is NOT overheating.

Ed
Ed "Bert" Bertrand
email me!

jdv69z

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Re: 1969 Camaro Over Heating issue
« Reply #8 on: July 09, 2017, 10:55:41 PM »
Yes, back in the 60's the thermostats were 180 degree, which means they opened at this temp. Today my 2010 Camaro's thermostat opens at 190 degrees. In my first car, a 57 chevy with a 327, I could watch the water temp gauge needle drop as the thermostat opened at 180. I could even tell if the thermostat was sticking by the needle movement.
Jimmy V.

camaroman1969

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Re: 1969 Camaro Over Heating issue
« Reply #9 on: July 10, 2017, 01:57:17 AM »
Stinger 69   I have flow in radiator tank.  Is a "moderate flow" normal??  Or should water pump be moving more water faster???   I guess question is, what is a good flow rate???  Also, radiator is a repo one. 

JKZ27

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Re: 1969 Camaro Over Heating issue
« Reply #10 on: July 10, 2017, 10:04:48 AM »
What is your indicator that it is overheating? Temperature gauge showing above 195 or is it pushing coolant out of the radiator cap? Did it just start doing this?
John
69 RS/SS Cortez Silver, L48 MC1
68 RS Ash/Ivy Gold 327EFI M20

68Zproject

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Re: 1969 Camaro Over Heating issue
« Reply #11 on: July 10, 2017, 03:11:11 PM »
I don't think the repros have a "fill line" on them so are you filling it too full and thinking it's overheating because fluid comes out?  If so, you need to have the level in your radiator down 2-3 inches below the cap as that is "full".
68Z28

janobyte

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Re: 1969 Camaro Over Heating issue
« Reply #12 on: July 10, 2017, 08:35:29 PM »
To answer your flow question, simply put, faster is not better concerning coolant flow. Time is needed to absorb heat: block and heads. Then heat disipation, through the radiator. Thermostat is a variable resistor, so to speak, which controls the coolant flow. What you are calling moderate dictates flow, which indivates its opening. How are your hoses? Bottom one will start to collapse with age, hence add restriction to flow.
68 Z/28  born with: 302, drive line, etc..

janobyte

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Re: 1969 Camaro Over Heating issue
« Reply #13 on: July 10, 2017, 08:38:51 PM »
And yes to all the other posts.
68 Z/28  born with: 302, drive line, etc..

maroman

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Re: 1969 Camaro Over Heating issue
« Reply #14 on: July 10, 2017, 09:24:28 PM »
I'm wondering about your comment about " 185-190 in and out." Where is in and out?
Doug  '67 RS/SS 396 auto I know the car since new

Leon in Mn.

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Re: 1969 Camaro Over Heating issue
« Reply #15 on: July 11, 2017, 12:13:09 AM »
Do you have the correct fan spacer?  The fan should not be too far into the fan shroud.  It should only be in slightly as to pull air out.  In too far just causes fluctuations in air flow.  You did say that you found the fan touching the back of the radiator?  Just throwing thoughts out there..........also 190 is not too hot.  Many engines with electric cooling fans, (I know yours is not),  did not kick their electric fans on until around 230 degrees Farrah Faucett.  :)

camaroman1969

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Re: 1969 Camaro Over Heating issue
« Reply #16 on: July 11, 2017, 01:41:38 AM »
There is about a inch between back of radiator, and front of fan.  New clutch fan just put in.  We did not use a "spacer.  Nothing came in box when new one arrived.  ?

camaroman1969

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Re: 1969 Camaro Over Heating issue
« Reply #17 on: July 11, 2017, 01:43:20 AM »
"IN" is the hose at bottom of radiator, and "OUT" would be hose at the top of radiator.

bcmiller

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Re: 1969 Camaro Over Heating issue
« Reply #18 on: July 11, 2017, 02:03:56 AM »
My 468 runs at 200 to 205 on a hot day. And that's not overheating.

If you are not pushing coolant out, I wouldn't worry about it.

Bryon / 1968 Camaro SS 396 - now 468 ci, M21, 12 bolt
Looking for 68 Camaro with body number NOR 181016

camaroman1969

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Re: 1969 Camaro Over Heating issue
« Reply #19 on: July 11, 2017, 02:10:00 AM »
This is to JKZ27......Heat indicator was the stock temp gauge.  Went all the way into the "RED Zone"  We are really stumped here on this heat issue.  We don't want to throw good money at this problem, and still have the same issue.  I read that article about "timing and Vacuum"......a lot of good advice here...may try some of those ideas.  Thank you to everyone who chimed in on this issue.   If you have some solid info, please post it.  I need to get my 69 Camaro up and running again.   Don

camaroman1969

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Re: 1969 Camaro Over Heating issue
« Reply #20 on: July 11, 2017, 02:12:59 AM »
bcmiller.....My Camaro ran good last season...mid-way in the gauge.  Car ran good.  Now when it approaches the 3/4 point into the gauge, car goes crazy.  Won't idle right, shifts hard, etc.  This block is really touchy.  Major headache.......

68Zproject

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Re: 1969 Camaro Over Heating issue
« Reply #21 on: July 11, 2017, 03:22:12 AM »
You might have an air pocket too in your system.  Leave the cap off for a while and let it run until the thermostat opens and you get radiator flow.  Keep the revs up for a while and notice the flow and see if there are bubbles or there's a spot where it doesn't flow for a bit and then starts again.  Might be air getting displaced if that happens and the coolant level will go down.  If so keep doing that until you are sure all the air is gone and top off.
68Z28

bcmiller

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Re: 1969 Camaro Over Heating issue
« Reply #22 on: July 11, 2017, 03:40:51 PM »
You might have an air pocket too in your system.  Leave the cap off for a while and let it run until the thermostat opens and you get radiator flow.  Keep the revs up for a while and notice the flow and see if there are bubbles or there's a spot where it doesn't flow for a bit and then starts again.  Might be air getting displaced if that happens and the coolant level will go down.  If so keep doing that until you are sure all the air is gone and top off.

Good idea! Zero cost to do this, and it may fix the problem.
Bryon / 1968 Camaro SS 396 - now 468 ci, M21, 12 bolt
Looking for 68 Camaro with body number NOR 181016

bcmiller

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Re: 1969 Camaro Over Heating issue
« Reply #23 on: July 11, 2017, 03:52:41 PM »
There is about a inch between back of radiator, and front of fan.  New clutch fan just put in.  We did not use a "spacer.  Nothing came in box when new one arrived.  ?

Sounds too close.

Are you running a shroud?  How about some pics?
Bryon / 1968 Camaro SS 396 - now 468 ci, M21, 12 bolt
Looking for 68 Camaro with body number NOR 181016

Vince

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Re: 1969 Camaro Over Heating issue
« Reply #24 on: July 11, 2017, 04:18:22 PM »
I'm just throwing this out there as it happened to me.  My car started running hotter than its regular norm and started dying at a stop and being really hard to restart.  It usually didn't restart until it sat and cooled down awhile.  It turned out that the heat riser valve in the passenger side exhaust manifold had frozen shut. 

68Zproject

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Re: 1969 Camaro Over Heating issue
« Reply #25 on: July 11, 2017, 04:26:43 PM »
There is about a inch between back of radiator, and front of fan.  New clutch fan just put in.  We did not use a "spacer.  Nothing came in box when new one arrived.  ?

Sounds too close.

Are you running a shroud?  How about some pics?

My stock set up with a shroud has about 5 inches from fan to radiator and the fan sits half in and half out of the shroud. As bc said, pictures would help.
68Z28

ban617

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Re: 1969 Camaro Over Heating issue
« Reply #26 on: July 14, 2017, 03:41:27 PM »
What is the temp of the new thermostat that was replaced ? What compression is the engine & what size is it ? Could it be the sending unit for the factory gauge , I had one bad once & thought it was overheating but it was just the sending unit ... it doesn't have a serpentine system on it does it ?

camaroman1969

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Re: 1969 Camaro Over Heating issue
« Reply #27 on: July 18, 2017, 12:04:08 PM »
Hi!  Thanks for your time on commenting on my issue.  We replaced thermostat with a 180 F one.  It's a "high flow one".  I have a 1969 Camaro SS/RS 397/375
car.  Comp. ratio is 11.0 to 1.  Pretty much all factory set-up.  No serp. belts being used here....factory originals only.  It could be a bad sending unit.  I think I'll change it out just so I know what I have here.  Actually, yesterday, we installed a new "pusher fan" in front of radiator, for added insurance when car is driven.  I have a 4 core, 4 row radiator in it now.  Well, this is where I'm at Ban617.  Any other ideas will be welcome.  Thanks for chiming in.    Don

uscrichter

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Re: 1969 Camaro Over Heating issue
« Reply #28 on: July 21, 2017, 11:13:38 PM »
I have had the problem with several big block restorations in the past and was the problem posted by 68z28 with the air pocket issue on both Camaros and Corvettes with big blocks and have successfully fixed the issue once by running the car without the thermostat and cap off for better flow, however on two accessions I literally had to raise the front end of the car 12" inches while purging the system so that the water could purge the air pocket in the water jackets and both times this procedure worked and for some reason have not had to raise the front of the car to purge small blocks that I have built. Good Luck!

rich69rs

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Re: 1969 Camaro Over Heating issue
« Reply #29 on: July 22, 2017, 12:28:41 AM »
I'm just throwing this out there as it happened to me.  My car started running hotter than its regular norm and started dying at a stop and being really hard to restart.  It usually didn't restart until it sat and cooled down awhile.  It turned out that the heat riser valve in the passenger side exhaust manifold had frozen shut. 

My suggestion is that you throw the heat riser valve out in the snow and replace it with a "donut" in order to avoid the very problem you mention.  I got rid of mine a long time ago. Only thing I do to compensate is a few more seconds at idle after starting cold.

Heat riser valves you get today from anywhere are junk IMO and you are just asking for trouble if you install one.
Richard Thomas
1969 RS

Sauron327

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Re: 1969 Camaro Over Heating issue
« Reply #30 on: July 22, 2017, 04:06:34 PM »
The last four "overheating" issues I diagnosed were not overheating problems at all. They were faulty sending units or gauges. Helps to have good spare gauges hanging around, or an IR gun.

Vince

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Re: 1969 Camaro Over Heating issue
« Reply #31 on: July 22, 2017, 06:05:38 PM »
I'm just throwing this out there as it happened to me.  My car started running hotter than its regular norm and started dying at a stop and being really hard to restart.  It usually didn't restart until it sat and cooled down awhile.  It turned out that the heat riser valve in the passenger side exhaust manifold had frozen shut. 

My suggestion is that you throw the heat riser valve out in the snow and replace it with a "donut" in order to avoid the very problem you mention.  I got rid of mine a long time ago. Only thing I do to compensate is a few more seconds at idle after starting cold.

Heat riser valves you get today from anywhere are junk IMO and you are just asking for trouble if you install one.
I agree.  What I had done was to have the flapper in my heat riser valve removed and the holes welded shut so basically it looks like it is still there from the outside, but there is no inside flapper anymore.