1969 Camaro Over Heating issue

[camaroman1969]

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]

Will not correct it - but get an infrared heat gun to figure out just how hot it really is first!

[ssl78]

Does it overheat when idling or cruising.

[77thor]

I would start with the thermostat...

[WorkinProgress]

Is there a fan shroud in place?

                             - Warren

[camaroman1969]

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]

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]

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

[jdv69z]

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.

[camaroman1969]

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]

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?

[68Zproject]

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".

[janobyte]

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.

[janobyte]

And yes to all the other posts.

[maroman]

I'm wondering about your comment about " 185-190 in and out." Where is in and out?