Hi all . . OK hopefully someone can help me out. My 68 with a 350 I just purchased recently is having cooling problems. Up here in MI this past weekend it was pretty humid and hot, took the car out to have a paint match done on it in normal driving and it goes up to 210, maybe slightly higher. I put a new 160 stat in it along with a new cap, the cap was junk and wouldnt hold any pressure. I still get the same thing letting the car run in the gargage and the upper hose always stays hard like the stat isnt opening. I added about 1/2 - 3/4 of a gallon of antifreeze and it didnt seem to help. The gauge sending unit is in the head which I want to move and put next to the stat where it should be for a more accurate reading. Also my fan shroud seems really short, the clutch on the front of the fan isnt even in the shroud. When I purchased the car the owner said when he bought it he thought it was a BB car but he realized it wasnt after some research so Im wondering if its a BB shroud since the fan is so far away from the rad. I have receipts showing he had the rad cleaned pressure checked and all that kind of stuff and he said it was a BB rad, since this is my first vette I cant say for sure if it is or not. A couple weeks ago me and the Mrs had it out for an 80 mile sunday roundtrip ride and since it wasnt near as hot out the car ran about 170-180, but if I recall I think I had the heat on medium cause the Mrs was a little chilled. So my questions are this:

What temp should this car be running at with a 350 in it?

Do I have the correct shroud? Will gladly send a pic to anyone who wants to see the setup so they can see for themself what Ive got . . . cant figure out how to load pics.

Can having the gauge sending unit in the head be reading a temp thats really far off what it actually is? Just a reach here but since the upper hose seems to stay hard maybe the temp is reading so far off of what the actual temp is that the stat hasnt opened yet . . . liek I said just a reach and wishful thinking.

Need some help guys!! Thanks in advance!
Chris

Whats the norm to do for hot running vettes, was thinking of putting either electric fans or a new aluminum radiator

 

Maybe your fan clutch is worn out. Give the fan a spin by hand as hard as you can (with the engine off ). If the fan spins 360 degrees or more your clutch is slipping, therefore your fan isn't spinning fast enough. Just an idea.

 

Your temp should run at the middle of the temp gauge when hot. Post us a picture of your setup though so we can see the shroud and the fan.

 

There were a couple shrouds and radiators for 68. Need to know if the car originally was a 300hp or 350hp 327. Also need to know if its auto and if it has air. PM or post a pic, I can compare it to mine.
BTW, the rad and shroud for the 300hp, 327, manual, no air is VERY marginal. You will see 210 temps on hot days.
Gary

 

http://www.snapfish.com/thumbnailsha...69/t_=26991973

Ok try this, there are three pics there.

 

Hi gary, thats what this car came with originally. It was a 327 3spd car but now has a 69 350 in it. The clutch on the fan doesnt even go into the shroud. I just posted a link for all to check out.

Sorry meant it was a 327 4 speed not a 3 speed, even with a new 160 stat the upper hose does not get soft when the temp is up near 200 or more? I guess I could have gotten a bad stat but the temp did the exact same thing with the old stat in it and when I changed it it still looked very good . . never actually tested it though

 

That link opened to a login page. Can you post pic here or PM to me.
Does it have AC?

 

HOW IN THE HELL DO YOU POST PICS HERE???? Gary, cant email you says you choose not to be emailed.

No clue if this will work or not, really crappy not being able to post directly to the forums!

http://www.snapfish.com/slideshow/Al...88/t_=26991973

 

Still no pics on that link.
Just turned my email on.

 

Gary, look for an email! thanks!

 

My .02:

If your stat is stuck shut your temp guage will peg to the right = totally overheated.

The stat has it's own internal temperature sensing mechanism and is completely independent of the car's temperature guage and the temp sending unit location has not affect on the thermostat.

I also had a lot of trouble finding a rad cap that sealed properly. None of the AC delco repro caps seemed to work. I finally found a stant cap that works well.

I sealed all around my radiator with pipe insulation to make sure air went through the radiator instead of around it.

I have a bigblock, and took many steps to improve the cooling and prevent overheating. I made very very small improvements that added up to marginally better performance. The one thing that helped dramatically was installing ceramic coated headers!

 

Got it. By the looks of the shroud, rad, and upper hose. That's a small block rad for use with A/C or maybe auto tranny, or big block.
Good news is that it's not even the small radiator (I know, mine is!).
Also know that a 160 thermostat wont affect your overheat temp, it will just take longer to get up to the overheat temp.
First off, does it overheat at highway speeds or just around town & idling?
If at highway speeds, the fan & shroud dont do much.
Stuff to check:
1) Plastic chin spoiler, bolted to lower valance. Increases air flow at higher speeds
2) Valance seal, rubber seal that directs flow over front crossmember cover plate.
3) radiator to support seals, foam
4) hood to rad support upper rubber seal
5) shroud to radiator seal
6)Lower rad hose, be sure it isnt collapsing
7) rad flushed and good flow
8) fan clutch
9) some shrouds had extensions. Look in Dr Rebuilds catalog/website. They have pretty good diagrams of the shroud for various models/years.

 

Can you elaborate more on the pipe insulation thing?? The car is a total restore so its not due to old crappy parts. What should be normal temp for a SB in a vette? Maybe this is just the way it is and I have to live with it but 210-220 just seems to high to me.

 

The pipe insulation he's referring to is for the shroud and/or rad to support seal. Very necessary for air flow through radiator. Again Dr Rebuild has good diagrams of the seals.
BTW, mine runs around 200 on mid 80-90 degree days, on or off the highway. Never overflowed the tank though. I also use a flex fan w/o fan clutch.

 

Gary, its the cruising around and stop and go that it does it at. Its not overheating, as I mentioned maybe Im just paranoid to see it get to 210-220 . . not use to that. Thanks I'll check all these things. So your thinking its a SB rad and not a BB rad? The car is a 4spd with NO A/C.

 

For a '68 327/3spd car, the original fan shroud would have been a metal cylinder a little larger than the diameter of the fan. It would not have covered the entire radiator. AT, AC, and big block cars got a larger radiator (4 row) and a full box shroud.

 

All true,

Not as mutch of a pro as some of the guys here but I just rebuilt my 69 350 (now 386). When I brought the radiator in it was at a loss of 25% flow and there were times prior that I hit 210 or even 230. A SB Chevy key operating temp is 190 - 210 per my race track days. Also I have a flex fan no clutch set up and my fan is not "perfect" fited into the shroud either.

First thing I would do is Swap out the clutch fan for a flex or just get rid of the clutch.

Second thing I would do is pull the radiator and get it tested. I know you mentioned it was a full rebuild but how long ago was that. A full radiotor sitting will loose flow faster than a daily runner.

I had my 4 core re-cored and ran me $350.

 

Well mine is definately plastic and covers the entire rad, the fan is about 1 inch away from the shroud which to me seems like its to far. I'll probably look for a short spacer since its alot cheaper than a new shroud and easier to do than fabricating an extension for the shroud.

 

Easy is right. The 300hp 327 cars had the metal tube + little rad. 350hp 327, AC and/or AT, or big block got the larger rad with full plastic shroud. From the pic, it's the large rad with full plastic shroud and SBC upper hose.
From your pic, you look to be missing the shroud extension that would partially cover the fan blades.
BTW, the extension is 2 piece, about $100 for each piece.

 

The restore was probably completed 5 years ago but like you mentioned the car was not driven very much. Correct me if Im wrong but isnt one purpose of a clutch fan is to save HP? Do wyou get better airflow through the rad with a clutch fan or a flex fan? Im not worrying about HP here, its a cruiser not a neck snapping torque machine the car I sold to buy this.