KevinG

Just when I thought my project C3 that I purchased was road read. Car is running hot, even on the highway. Come to find out the radiator shroud has HUGE gaps and isn't even touching the radiator except for the top. The bottom looks to have almost like a 3" opening while the sides range from 1-2".

How can I seal this up? Am I missing any pieces?

Drivers side:


Passenger side:


Inside fan shround facing down:

Mooser

Although I'd go ahead and put the foam seals in anyway (I can say this for sure since I've got the seals ready to put into mine)
Before I (you) go down that road (in case your going anyway)
Take some foil tape (the aluminum stuff they use for duct work) and seal everything you've shown and see if it helps your temp problem.

My 72 BB is/was missing every piece of foam except the one to the hood, had gaps etc much like you show. And never gets above about 200-205 even after a highway run and then into traffic. Normally runs right around 190.
Mooser

Sully1882

when going down the highway shouldn't the temps drop even without the shroud seals and all? Do like Mooser suggested and see if it helps. But I'm afraid that there might be more than just this causing your cooling system to not function correctly. When was the last time you went through the system and flushed it?

Sully

Roco71

Seal kits run between $20- $50 depending on applications and then there is a seal that goes across the top of the radiator that seals the hood.
Was your car running hot before the new engine?

7T1vette

Does your car have the stock air dam underneath the nose of the car? If not, that is likely your problem, as that deflector is needed to direct incoming air UP through those holes in the lower valence and into the radiator. If that little spoiler is missing or badly damaged, your car might run hot on the highway.

KevinG

Thanks for all the replies guys. I guess I left out some info.

-on a 96 degree late afternoon, the temp was around 210-220 while driving on the highway. Later in the evening on the way home, the car was hovering around 190-200 at night time.

-doesn't have front lip spoiler (was removed when it was painted)
-engine has less than 100 miles (Blueprint 355)
-never had center guage cluster hooked up when I was testing the old engine out. That engine dropped out 3 cam lobes.
-new 160 degree thermostat was installed (recommended by Blueprint engines)
-New waterpump installed onto new engine

I'll re-install the lip spoiler, put some foam seal on the sides of the shroud and the foam seal at the top of radiator support and see what that does.

Happy 4th of July!

gq82

Install the air dam and get the proper shroud seal kit....Paragon is a very good vendor for correct parts. You should definitely see a difference.
https://www.paragoncorvette.com/corv...c3/#/73/zoomed

trw

-doesn't have front lip spoiler (was removed when it was painted)

Not enough frontal area to pull/push air through the radiator without sucking it up from underneath.

Front spoiler will help greatly.

Easy Mike

The steel shrouds do not necessary fit right up to the radiator core. Yours looks like it could come forward a little. With the steel shrouds, the foam radiator support seals become critical. Make sure all of them are installed.

Put your chin spoiler back on.

Roco71

My best friend who's pretty much on top of his game told me that a Corvette with a properly sealed radiator will run cooler with the hood closed that it will with the hood open at idle.

scottyp99

Really? I wonder if that great, big piece of the hood that sits right in front of the radiator when it's open has anything to do with that?


Keep the shiny side up!
Scott

DaveL82

My 80 would run hot and I tried to fix it with different fans but no use. It's amazing how much pressure it take to move air through the rad so it goes around through every hole possible.

Rad must be sealed to the core support top bottom and sides. Shroud must also fit to rad and core support with no holes top bottom and sides. Don't forget the seals that go on top of the core support and seal to the hood. If any of this is missing it will cause an overheating issue.

Once I fully sealed mine no more problems even with the ac on.

Roco71

I think he was referring to the seal on the hood forcing air through the radiator, But you got a point there.

KevinG

Ok, I pulled off the fan to get access inside the fan shroud. I picked up HVAC pipe insulation, the biggest I could fined since there was a 2" gap on the bottom. This pipe insulation has adhesive on the slit, once in position, you pull the plastic and bond it to the surface.

Here's pics of the fan shroud sealed up on the sides and bottom:


And heres the top of the fan shroud to the radiator using the same material:


I also put on the front lip spoiler.

Took it for a drive and 10 minutes into my drive, my temp was reading this:


30 minutes into my drive, the temp was reading this:


Before, the temp guage was at the mark between the 210 and 250 in stop/go traffic


However I didn't put on the insulation piece on top of the radiator support that touches the hood - is that piece really important?

RU7376vettes

Yes, you want all air possible going through the radiator not around it. Your new motor will probably run a little hotter until it is completely broken in, but get the lower 'cow catcher' on it to deflect air up through the radiator and seal it all up to make certain it all goes through the radiator. You might also consider getting a water pump that has higher flow rates like an Edelbrock. I had heat issues with a 76 that had new radiator, well sealed and a GM Performance water pump. Ended up changing the water pump to the Edelbrock and all issues went away.
Just another opinion.

Unk

7T1vette

Remove the thermostat and run it again. It will take longer for the temp to stabilize...but it will. Let us know what the temp is when it does stabilize.

diehrd

Is that a 4 core rad ?

joewill

don't rely on your temperature gauge to tell you what your exact temp is.

people will tell you that a stock setup with all the shrouding and foam seals are entirely adequate and are engineered correctly. This is true, if you have correct flow and no radiator plugged up. thru the years your system will lose efficiency.

a good flush, engine and radiator, fresh coolant, and a 160 degree thermostat should help the most. ultimately you may have to seal up your shroud, your hood and your spoiler/dam. the 160 thermostat is a work around and is somewhat against convention, since you do want your engine to run at temps designed by GM and for emissions.

My big block would spit a little after shutting down with a 195 thermostat in it after driving just around town. Although I could have been overfilled. I have a good tight shroud, but no foam seals. taking the thermostat out barely caused the temp gauge to move. a 160 was just right. I have no problems on the highway.

69Vett

after installing an engine, it is very difficult to get all the air out.
I recently installed a motor had the same problem, except mine was sealed up tight.
I must have refilled the radiator 4-5 times thinking its good.... Nope.
you got to get all the air out and it is difficult with the corvette configuration.
I finally dissconnected the radiator hose at the radiator and kept pouring water into the hose until it ran out the top of the radiator,
buttoned it up, and it went right to the themostat setting and stayed there, it worked perfect, after I got the Air out of the system.

RedZR

I am a firm believer (now) in those shroud seals. I redid all mine on my 78 and really sealed the shroud on the ends and the top. Although the car never overheated before, it does run cooler. I can drive it on 100* days with the air conditioner on and the temp never reaches 200* with the 180* thermostat. I would seal the top as well.

Dan