My 66 had a worn out radiator did something like you describe, new one fixed it,
However,
He posted he has a new 4 row aluminum radiator from summit,

So back to the ops issue,
His other thread was about the lower radiator hose collapsing,

Isnt that suction side trying to pull coolant and cant, so stick a spring in it or get a hose that cant collapse and problem solved?

Perhaps not,
Just because the hose cant collapse doesnt mean its moving coolant,

New water pump new radiator,

Bad stat could block flow seems he tried it with no stat, so then what else would slow or block flow, some blockage in the engine.

Yeah, im reaching but feel like we are missing pieces to this puzzle,

 

Just a thought but when you have the engine running, radiator cap off are you getting circulation? I saw a similar post recently with a new radiator install and the issue was caused by not removing the plastic caps (dust covers) inside the radiator outlet/inlet that come from the rad mfg. They were located just inside the inlet so unless you were looking for them they can be easily missed and attached your hoses without removing them. It would cause your rad to not circulate.

and make sure to burp it to get all the air out.

 

Wouldnt that be a kicker if it was trapped air....

 

Newer hoses don't have springs, but are made that they are not needed, maybe stiff enough or whatever.
The only hoses I have ever seen collapse are old soft ones without inner springs.
Again, a restriction to flow can causes this, but it must be severe, otherwise the pump, being centrifugal, will just cavitate.

The only reason Stewert recommends and sells a RS tstat with 3 holes in it is because their pumps have the bypass blocked off for the gen1 chevy 350. That bypass guarantees enough flow thru the engine during warmup to eliminate any hotspots that could damage the castings. The downside is that it will ALWAYS BYPASS some coolant thus reducing the heat exchange lowering the performance of the cooling system. Blocking the bypass puts ALL of the coolant thru the rad even at warmup.

The other big advantage of the RS tstat is that it has a PRESSURE BALANCED design Meaning that the increased flow of coolant will not force the tstat to close a small amount or even completely.

At this stage, before getting into the engine, I would,

1-Gut an old tstat and use the washer part as a restrictor. The hole size is rated for close to the same temp as what the tstat was rated for. ( I didn't see the OP ever post the temp of what he was using).

2-Make sure the bypass on the pump is blocked off whether by the casting itself, a dowel, a set screw or even just a special gasket.

3-Adjust the timing to 34° @4000 rpm and make sure the advance weights all work freely and the vac advance works properly.

4-Burp the air out of the system properly.

5-Make sure of proper pressure cap and airtight suction hose to overflow tank.

6-When testing run the electric fans ALL the time

7-Measure in IN and OUT temps of the radiator. (hold the gun only an inch away from your target)


Other areas not addressed are a carb lean condition (which if factory, it should be quite lean, but correct and also can be richened a bit for cooling) and the internal auto tranny cooler. This can always be eliminated to help the cooling system substantially.

 

Here are the fans I got
https://www.summitracing.com/ga/part...9122/overview/

Here is the rad
https://www.summitracing.com/ga/part...4031/overview/

I am using an airlift on the car today to make sure there is no air being trapped in the car.

 

Did you read the reviews of that fan?

 

Um, the reviews are not epic,

The fans likely do not put out that much cfm on a radiator, cfm ratings in many cases are sad to say bs,

in addition the only place that type fan with its built around blade shroud pulls air is where its covering the radiator a donut shaped flow stream,

i didnt do the math to see how close to the reccomended 80 percent you are but a lot of radiator is wasted,

Not saying these fans wouldnt cool your car on that radiator, they very well might, the fans are just for idle and slow speeds,

the test is the vehical at speeds, if it still overheats driving you still have a problem and the fans are not the problem

 

I think my sender or the gauge is acting up also, showed I was running cool (160-170) 2 months ago, replaced t stat (orig was a good after market, not that old or many miles on it) was running 180/200 after that, now showing going to 210+ on start up, flip the efan overide , kinda behaves, flip hood up, check temp gauge on rad cap(mr gasket type) running at 160 in rad, gauge inside @ 200

fiddled with the set points on the flexalite efan control , thinking that is not working correct

I am putting a mechanical gauge under the hood in the head port, for another check point

really suspect the sending unit for the inside gauge

Willcox sells an adjustable resistor if you buy an aftermarket sending unit(looks PIA, tear dash apart to put in resistor AND calibrate it), or just buy a sender from the corvette vendors @ $25 that are supposed to be spot on. I will be buying the correct sender from a corvette vendor

probably an infrared lazer non touch sensor would tell me, but hunting down one of those that is accurate has become another issue

 

Not that this may be of any good to you.

Recently I had worked on a 1986 that had the radiator cap with the temp gauge built into it and when I pressure tested it ..it was bad....and the owner stated that it was not even a year old. So I put a AC Delco one on it instead.

Also..I use a racing temp gauge that I know for a fact that is good and reads sport on...so your idea of installing another gauge to verify your temps is worth while in my opinion. Which I recently also had top deal with on a 1978 I had worked on that was getting hot when the A/C was turned on.

http://www.corvetteforum.com/forums/...warning-2.html

As for your gauge in your gauge cluster....as I have been told by the guy who restores my gauges. "The gauge is only going to read what it is being told to read." So...if the gauge is working....98+% of the time it is the sending unit giving a false ohm reading to the gauge to make it read incorrectly.

DUB

 

Im not a big fan if how many factory gauges read out even when they do work well,

I never much liked the c3 temp gauge and every car i have owned i have a high quailty temp gauge under the hood for second opinions,

A buddy was telling me about his oil cooler install and he had a feature i find really super trick,

Both inlet and outlet temp gauges so he really knows whats going on.

 

Wow 89 posts, trying to figure out if I should read them all!

I have seen guys mess up the flow thru the engine compartment with fans! Push or pull?

Glancing I saw a bunch of good tips from head gasket coolant holes to radiator hose springs!
Trying to isolate the problem!

I would try a few things like prop the hood up to see if that helps on a drive!

I would get a temp gun to check out variations of tune cylinder to cylinder, on exhausts like if you have headers, valve cover to valve cover, $hit read the temps on springs and retainers, check everything out, etc etc

i would buy a cheap new gauge and temp wire it to verify existing gauges!

I would detune it to it to a very mild tune (lazy advance) just to see if any change occurs!

Run a lightweight oil if the pressure is not an issue- like a 5w-30 to see if the bearing clearances are so tight! The rule is 10 lbs for every 1000rpms, and shut it off if you don't have that!

Jet it fat! Run it purposely rich!

Run a true higher octane gas!!

And on on and on and on! Till you nail it!

 

OP, feel free to continue the thread. The conflict/hijack posts have been removed.

 

Did you ever get the cooling issue figured out?

 

Have you made any recent progress with your cooling issue?

 

I too wondered about this, though I think it would heat up faster and more severely.

What about pulleys? Using the stock ones, or underdrives? And going back to pump rotation, are you using the stock pulley arrangement, or have you converted to a serpentine setup?

Good Luck!

 

I still have not figured this out. I pulled the engine and is in the process to put it back together. I can see nothing wrong with the build. No excess rtv, no visible blockage. I am going back with a different head gasket that has larger holes in the water passage. I will be putting a oil cooler on it as well. The only thing that I found is the oil pump strainer was a little high so I will be addressing that(never had a drop in pressure though). Is there anything I should do to check the water passages I can't see.

thanks

Geo

 

My ex-boss had a racing Vette that had a similar problem. He told me that in the end he solved it with a higher volume racing water pump (that I think he got from Summit). Maybe the others here will chime in regarding that. Good luck!