rocknroll Posted August 26, 2014 Share Posted August 26, 2014 Hope someone can help. I've restored a few rods but this is my first Vette. 1978 25th anniversary. I can't keep it cool and not sure what to do. So far, it has a NEW aluminum 3 core radiator with 3/4 inch cores. New water pump, and the new engine has about 600 miles on it. Bored 60 over. I am told it will run a bit hotter while new and because of the 60 over bore. idling or driving casually around the park it is OK. but on the highway it starts to get hot. I can't get more than about 10 miles at 75 mph before it's time to stop and let it cool down. I changed the radiator cap first, no luck. I checked the water pump, it's working. Full of antifreeze. it has a flex fan, the only thing I can think is perhaps the radiator just sin't big enough, or perhaps the flex fan flattens out at high speed and doesn't cool. But even if the flat flex fan were the case, wouldn't the air blowing through the engine compartment do the trick ? I don't want to blow the bucks on another new radiator and find out that wont fix the problem. If anyone has any answers please help !!! I am on a time crunch here and have to have this on the road soon to be delivered across country to some family. Can anyone help ??? Thanx ! Rock N Roll ! Link to comment Share on other sites More sharing options...
rocknroll Posted August 26, 2014 Author Share Posted August 26, 2014 P.S. How do I add a picture to my mebership thing ? Link to comment Share on other sites More sharing options...
Desertdawg Posted August 26, 2014 Share Posted August 26, 2014 Is there a thermostat in the motor? Are the rubber air dams underneath the front to direct air to the radiator. Is there a plastic bag or other trash that got sucked up into the front blocking air flow??? To add a picture click on the little arrow next to your name on the top right of this page. Click on the "My Settings" Click on the change picture button... Link to comment Share on other sites More sharing options...
Desertdawg Posted August 26, 2014 Share Posted August 26, 2014 Is the spring in the lower radiator hose? Squeeze the lower hose when it's cool, you should not be able to flatten it... Link to comment Share on other sites More sharing options...
rocknroll Posted August 26, 2014 Author Share Posted August 26, 2014 Thanx DesertDawg, there seems to be a spring in the lower hose. It appears to have been installed in a tight sqeeze, if I had done it myself I would have trimmed the length a bit so as not to put such a sharp turn in it, but it doesn't look like it is so tight that it would cause a heating problem. There is no trash or anything in front of the grill or blocking anything, but there are no airdams on this car. only the stock front end, no spoilers, etc. is this something I'm gonna need ? There was a 180 thermostate but I removed it to see if that helped. It takes it longer to get hot now, but it still gets there. That and the radiator cap were the first things I checked. If you could point me in the right direction I would sure appreciate it ! Link to comment Share on other sites More sharing options...
LastC3 Posted August 26, 2014 Share Posted August 26, 2014 You'll definitely want to keep the thermostat in there ... and 180 should be fine .... When you get the car good a warm, exercise the heater function ... you could still have a little air in the system .... The flex fan certainly isn't helping you much ... Either go back to OEM solid blade with a clutch .... or a pair of electrics ... Also make certain basic timing is where it should be ... Link to comment Share on other sites More sharing options...
Ted Y Posted August 26, 2014 Share Posted August 26, 2014 How hot is it getting? Link to comment Share on other sites More sharing options...
Extender32 Posted August 26, 2014 Share Posted August 26, 2014 My wife has a similar setup in her 78' too however, there are a pair of electric fans that are wired to run continously. Her car runs about 200 dg all the time. I'd get rid of the flex fan and get a pair of electric fans, this should help keep your ride cool. Link to comment Share on other sites More sharing options...
Guest badbobs95 Posted August 26, 2014 Share Posted August 26, 2014 Not sure what you mean when you say "no air dams". 78s do have three piece air dams. There is a center piece and two corner pieces. I know because I've been helping to restore a 78 for the last week. Can you post up a pic of the front end? The center air dam is a must. Link to comment Share on other sites More sharing options...
Mregor Posted August 26, 2014 Share Posted August 26, 2014 Need to seal up all areas around shroud and radiator. At speed on highway, you should be getting plenty od air flow to cool. Your airdams and seals need to funnel all the air through the radiator. Link to comment Share on other sites More sharing options...
Guest badbobs95 Posted August 26, 2014 Share Posted August 26, 2014 http://www.web-cars.com/images/vette_img/DSC_8191A_a.jpg Should look like this Link to comment Share on other sites More sharing options...
Shifty Posted August 26, 2014 Share Posted August 26, 2014 I'd definitely look at teh basics....fix that air dam being #1. Get a t-stat back in it to slow down teh coolant, and give it a chance in teh radiator for your fan to cool it #2, and get a real fan (or better yet a pair of bad-ass electrics) #3. If that's still not doing it, you may want to pull that water pump, and either go with a Flow-Cooler (or teh like) pump, or at least a disc on teh impeller. Link to comment Share on other sites More sharing options...
HOXXOH Posted August 26, 2014 Share Posted August 26, 2014 Also take a close look to make sure the AC condenser is clean and free of crumpled fins. Overheating at highway speeds where the RPM is low and constant, but not in town, isn't a fan problem. It's more like an air flow issue being different than the original design. Link to comment Share on other sites More sharing options...
Desertdawg Posted August 26, 2014 Share Posted August 26, 2014 Need to seal up all areas around shroud and radiator. At speed on highway, you should be getting plenty od air flow to cool. Your airdams and seals need to funnel all the air through the radiator. Yeah... nice reminder...You NEED to have all those pieces of foam in there to force the air thru the radiator... Link to comment Share on other sites More sharing options...
F22trainer Posted August 26, 2014 Share Posted August 26, 2014 ok, maybe I can add something...great thread with good info from the ACE team, especially Dawg's pic of the seals - yeesch, I had no idea there were that many seals in the C3 cooling system. But yeah, those air dams are critical. I replaced mine about a year ago or so, just after I got the new engine done. The original was still intact, but distorted and kinda folded too far aft. Replacement made a significant difference at freeway speeds. I do know one of the tricks they did on the C4R's was to remove the aft hood seal near the door fronts - they had plenty of air going in, but it was not getting out! I was also curious about the size engine - big block? (maybe I just missed that in the thread) But staying cool at freeway speeds should not be a problem if it is not depraved of airflow. I too agree with ditching the flex fan - electric upgrade would be a positive step in the right direction. Only other suggestion - stop by Bromley's and let Doug have it for a day or two. He'll have it dialed in by the time he finishes with it. Link to comment Share on other sites More sharing options...
Bromley's Corvettes Posted August 26, 2014 Share Posted August 26, 2014 Lots of good suggestions:) PM sent:) Link to comment Share on other sites More sharing options...
Bromley's Corvettes Posted August 26, 2014 Share Posted August 26, 2014 I have worked on corvettes that I put elec fans and alum rad and you can shut off fans at high way speed and temp does not go up. So like HOXXOH was saying probably not a fan problem. A 7 blade Big Block fan with H.D clutch should help around town so it wont get hot but high way your timing is off or air flow is limited or the block being 60 over core shift made thin cylinder walls and its just going to want to run hot no matter what you do. I no some tricks to help it out but I have a few customers that every trick in the book and it still runs hotter then it should. You would not believe how many Corvettes I have worked on with a new engine that distributor is a tooth off so timing is way way off made it run real hot and like shit and the guy been driving it around lol. Link to comment Share on other sites More sharing options...
Bromley's Corvettes Posted August 26, 2014 Share Posted August 26, 2014 Need to seal up all areas around shroud and radiator. At speed on highway, you should be getting plenty od air flow to cool. Your airdams and seals need to funnel all the air through the radiator. Yeah... nice reminder...You NEED to have all those pieces of foam in there to force the air thru the radiator... I no sometimes that can make a difference but my moms 81 has none of that lol. No shroud nothing and just a stock water pump and flex fan and stock old 2 row copper brass rad rusted in side and it has never gone over 200 even in bad traffic and most of the time runs 160 to 180 it has no t-stat:) Stock motor just alum intake carb headers x-pipe exhaust. In the winter we have to block off the lower half of the rad or it wont get to 160 lol. So something else is wrong when a car wants to run hot on freeway. Link to comment Share on other sites More sharing options...
dale68z Posted August 27, 2014 Share Posted August 27, 2014 Absolutely agree with needing the foam, and ducts in place. What kind of radiator do you have? Here is my brand new 3 row Champion radiator that would not cool my car. This radiator was 3 months old, it was the warranty replacement for the prior radiator that would not cool the car. I was sick of the "will cool 700hp" crap from the manufacturer. So, I cut it apart and found the answer to my problem. Crushed tubes, less than .030 tubes, that will not flow water. Basically it may have had one row that did not have crushed tubes on one end or the other. The engine was brand new when this rad. was installed, in 3 months many tubes had debris blocking the tubes. I bought a $310 shipped, Griffin 2 row 1.5" tube radiator and car stays nice and cool. Even when it is 100 deg. and running a road course for 15 minutes or more. Campion radiator next to a Griffin.... just a tiny bit of difference. The Griffin has an additional usable 7 rows of tubes. Link to comment Share on other sites More sharing options...
Bromley's Corvettes Posted August 27, 2014 Share Posted August 27, 2014 WOW what a crap radiator that was lol. No wonder it ran hot lol. Was it China made or what? Link to comment Share on other sites More sharing options...
Shifty Posted August 27, 2014 Share Posted August 27, 2014 WOW what a crap radiator that was lol. No wonder it ran hot lol. Was it China made or what? You oughta see teh crap that I'm forced to sell nowadays.... Link to comment Share on other sites More sharing options...
Bromley's Corvettes Posted August 27, 2014 Share Posted August 27, 2014 I hear you it sucks biz is hard enough and to get junk parts just makes it worse. Nothing like doing jobs twice because of crap parts failing or leaking right away;( Link to comment Share on other sites More sharing options...
dale68z Posted August 28, 2014 Share Posted August 28, 2014 WOW what a crap radiator that was lol. No wonder it ran hot lol. Was it China made or what?I was told it was made in the US. http://www.championradiators.com/aboutThese radiators are exactly the specs the OP said his was. 3-3/4" rows.rocknroll, look inside your radiator. Are your tube height small? The radiator pictured the tubes were smaller than .030. I could force a .030 feeler gauge into the tube. My griffin rad. is .080-.090" and has 1.5" tubes, 3" of tube total vs 2.25" in the 3 row champion. Link to comment Share on other sites More sharing options...
Bromley's Corvettes Posted August 28, 2014 Share Posted August 28, 2014 Maybe thats why hes running hot:) I not seen the 3 5/8 rows usually 2 1in or 1-1/8 rows. Link to comment Share on other sites More sharing options...
rocknroll Posted August 28, 2014 Author Share Posted August 28, 2014 BadBob.....thanx for the pictures. I have found 2 different kinds of air dams for this model. One of them is the 3 peice like in your picture. There aint ANY of that on my car. Might explain why it ran a bit warm before.......but now it's HOTTER. I found one on E-bay. Just to be sure I think I'll invest in that. Dale68, now I'm really scared. That is exactly the radiator I have. I was told it had an awesome warranty, and I have talked to TONY on the phone about it. Desert Dawg, thanx for the pics of the seals. The raidator shroud, supports, seals, EVERYTHING were laying out of this car for over a year waiting for the new engine to be built. I am not sure what remains of those seals. But glad to see a full illustration. I will know exactly what to look for. It will be 2 days before I get to work on this again because of my schedule. So for now I have new questions. (1) Where is Bromley's Corvettes ? (2) Where can I find a Griffin radiator for that price of 300 plus ? Looks like I may have multiple problems. I'll give a report in a couple days. Thanx for all this info !!! Link to comment Share on other sites More sharing options...
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