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When i slow down it cools off, when I’m driving at highway speed - it heats up! I just replaced my fan belts with NAPA version. I was running reproductions and I noticed that they are rubbery like a rubber band - maybe they are loosening up while driving???
i also replaced the temp sender, hoses, installed 160 degree tstat.
i was driving to Carlisle last year and got involved in some tail chase with a C2, and I almost overheated at high speed...
Marlon
Originally Posted by wadenelson
Ok, so here's my radiator story.
Short version: Bought a Champion on ebay, great radiator, good price, free shipping, cools great, really good decision.
My Vette had overheating "issues." You know how it goes. You're constantly have eyes on the temperature gauge instead of being unconcerned. You GET concerned every time traffic slows down to a crawl. It's no way to own a car, honestly.
So I put the pressure tester on, pump it up, and ...watch the pressure bleed off. Go around and tighten a few loose hose clamps, replace a couple of hoses. Go to replace the t-stat and the threads in the manifold strip. 2 weeks later I've got it helicoiled with a new 180 degree Stant.
(A missing t-stat or 160 degree t-stat is a guarantee a vehicle has been overheating, right alongside the electric fans PO badly installed & miswired.)
Test it again. Still won't hold pressure. This time my buddy spots a barely visible green spot in one corner of the radiator.
Pull the radiator. Take it to a radiator shop in Farmington NM who tells me it's leaking in all four corners, AND the tubes are "weak" "Blows up like a balloon when I put some pressure on it." Solders it up, doesn't charge me much, tells me "fine for a weekend driver, for everyday, go get yourself a new radiator"
This was an OEM brass radiator, Harrison, or look-alike.
Less than a month later cars running hot again and I can see drips in the driveway. I had purchased ANOTHER radiator, off Craigslist for $50 hoping it was in better condition, but....it's out in San Diego, and I'm in Phoenix. So it would need a pass through the radiator shop AND transport. And might not be any better!
I get on the web and see C3 radiators everywhere from $250 to $950. How the hell would anyone know WHICH one to buy?
Say "aw **** it" and order a Champion. Plenty of good comments about them. With shipping included I paid barely over $200 from an eBay vendor. Gotta like that.
Get around to installing it. The straps don't fit like they used to on top, but more than well enough to hold it in place. Overheat issues all gone. Best $200 I've ever spent. BTW the weld quality on mine was outstanding.
If anyone's doing a restoration, and wants my old one, for another pass through the radiator shop, drop me a PM. I might be able to ship it in the box the Champion came in. Or you can pickup in Phoenix.
If anyone wants an original radiator and is in SAN DIEGO, let me know and I'll pass the other one along to you for the $50 I paid for it. Condition unknown. Location: Del Mar. No delivery, no shipping. It's going to the recyclers if no one wants it.
FWIW I see brass, original STYLE radiators for around $450 PLUS shipping on the web. So it's probably worth a gamble and cost of repairs.
There's also getting a radiator re-cored. Basically they solder the end tanks onto a new core. You're looking a minimum of $500 for parts & labor for a re-core job. go on Youtube if you're curious about re-coring. A couple of great videos, despite idiot workers not wearing safety glasses while using torches...
Cheers!
p.s. Installation tip. If you loosen the metal shroud on a '68 top AND bottom you can pull it back and slide the radiator in easily. Up top there are FOUR bolts, look underneath and you can remove the bracket itself and give yourself another 2" of clearance, not scrape up your new fins!
I personally have not been a supporter of thermostats so that was removed day one giving a consistent unrestricted flow.
A thermostat that's working properly costs you nothing in terms of cooling or performance.
Instead of flow being adjusted based on coolant temperature, as you say, you're getting unrestricted flow based solely on engine, hence water pump RPM.
Not having a thermostat will cost you several things, like power, miles per gallon, not warming up as fast (so no heat or defrost AND more fuel wasted).
Your engine, specifically the heads, are designed to operate a bit above 200F. Fuel vaporizes the best, combustion is most efficient, etc. That's the temp the engineers who design it intend it to operate at. Your'e likely to get more carbon build up, and plugs that foul faster due to incomplete combustion. Not a lot, but some.
By adding ethylene glycol AND pressurizing the system to 9-10 psi the engineers prevent boiling from occuring in the head to well over 250 degrees. When coolant boils inside the head, overheating occurs, because water vapor (steam bubbles) can't remove nearly as much heat as liquid coolant.
When you pull the thermostat the head temps are going to be all over the place. Haul *** down a freeway on a cool day and they might never reach 160 degrees. Yes, they'll seldom get as HOT, but if you're overheating, a sticking thermostat is SELDOM the problem. (I only see thermostats stuck AFTER DIY'ers "flush" cooling systems with harsh chemicals. 2-3 days after they flush, car is overheating and a t-stat shaft coated with fresh metal deposits, freed by those acids, is why).
When I pull a motor apart and see a 160 degree, or NO thermostat, I can safely assume that car has been overheating and a DIY has made unsuccessful efforts to repair it. That and aftermarket electric fans that sound like a jet engine running...
There's simply NO BENEFIT to removing a properly working thermostat. Fix the OTHER problems in your cooling system and leave the t-stat alone if you're having overheating issues.
As far as bona fides, I've been fixing cooling systems since the days of the Jaguar XKE, a vehicle INFAMOUS for over-heating. The basics haven't changed. More than ANYTHING you must have no, zero pressure leaks in your system for it to cool properly.
Last edited by wadenelson; 02-22-2019 at 06:28 PM.
When i slow down it cools off, when I’m driving at highway speed - it heats up! I just replaced my fan belts with NAPA version. I was running reproductions and I noticed that they are rubbery like a rubber band - maybe they are loosening up while driving??? Marlon
When and where a car overheats gives you a clue as to where the problem is. Is it not moving enough heat from the engine to the radiator, or from the radiator to the air?
Your engine is MAKING a lot more heat at highway speed. That's a clue!
Why isn't your radiator able to get rid of that heat? Are you missing all the foam pieces that force air through the radiator and not around and under and above it?
Is your system low on coolant? Are you using a correct 50/50 mix?
Start by PRESSURE TESTING your cooling system. Auto Zone, some of those places will even lend you a pressure tester. No point checking, testing, doing ANYTHING else until
you know your system is holding pressure.
Is your overflow bottle working? Does it go up in volume when you check it hot, and lower the next morning when it's cool? A cracked hose to your overflow or expansion tank will cause you to
continuously lose coolant while hot, and suck air back in when it's cold.
Has someone tried to "fix" your radiator with stop leak? Black gunk in the radiator neck and overflow bottle? Bad news!
You might take your radiator out and get it boiled out at a radiator shop. $100. Just in case its clogged.
what usually happens is a cooling system develops a leak, and a previous owner (PO) starts topping it up with TAP water, and slowly clogs the radiator with mineral (calcium) deposits from the tap water.
I noticed in the parts house some years ago, that the new stats have the same opening for water flow no matter the temp rating of the stat.......many years/decades ago the opening was much larger.....increased flow of course....but during the 195 stat increase in temp by the EPA/.gov the new stats at that range had the smaller opening, so what if the stat opens at 160-180-195, IF the flow is restricted the engine will run at the higher temps.....BUT living in FLORIDA where the ambient in my back yard MAY be as high as 95f some daze, the road temps are of course much higher, what with the black ASSfault they use and stuck in traffic...so the stat really needs increased flow....so I took to drilling holes in the stat skirt, but found/thought it's much simpler to just shear the skirt off the stat ring, tin snips....sure engine take a tad longer to warm up, but so what?? point is the thing never over heats NOW......
Obviously a decent rad/shroud/fans/and proper stuffing to control the airflow through the rad, not AROUND it....especially at speed.....
I had a leak in the old radiator bought a champion $204 with shipping. Replaced the water pump thermostat hoses fan clutch and the rubber transmission cooling lines. The fit was very close could not get passenger side bracket to fit but driver side does along with the brackets for the fan shround which also hold the radiator in place. I was able to remove this and the old a/c condenser without taking off the hood. The car used to run at about 200 degrees but it doesn't get past 175 now, more than happy withe the radiator and with all new cooling I'm ready for some road trips.
I had a leak in the old radiator bought a champion $204 with shipping. Replaced the water pump thermostat hoses fan clutch and the rubber transmission cooling lines. The fit was very close could not get passenger side bracket to fit but driver side does along with the brackets for the fan shround which also hold the radiator in place. I was able to remove this and the old a/c condenser without taking off the hood. The car used to run at about 200 degrees but it doesn't get past 175 now, more than happy withe the radiator and with all new cooling I'm ready for some road trips.
Congrats on the install and cooler temps! I’m curious about something. The PO installed (what looks like) the same Champion radiator in our ‘72 Coupe. The lower hose rubs against the sway bar because the lower inlet is not crimped the way the OEM radiator was. Did your Champion come with a crimped lower inlet that many confuse for delivery damage? Ours did not. I’ve even lifted the radiator with additional foam on the lower brackets, but the hose is still contacting the sway bar.
Bought an 81 auto a few weeks ago with a blown head gasket and cracked head, Its all fixed now but having concerns about overheating. It has a new 180 tstat, water pump, hoses, radiator (oreilly 2 core plastic and aluminum) and temp sensors. When I go out for a drive about 25 miles 80 degree day the temp gauge starts out good warmed up with the needle at about 185. About halfway the needle goes to around 200. When I get back home the laser temp sensor has the tstat housing at 200 with the radiator plastic inlet at 180 the radiator outlet at the bottom at 140. It seems like it will stay at that temp idling in the garage. The fan shroud is on but i removed the black plastic piece from the air dam underneath along with the ram air stuff to the air filter. The driver side foam is missing. When I shut it off the clutch fan spins for about 3 seconds and stops. The coolant overflow level does not change and the hoses have good pressure for a few hours after. Remove the radiator cap after cool off and the coolant is as full as it can be without spilling out. I will put the air dam plastic back on and get the foam from ebay and see if it gets better. I would like it to just run at around 185.
Installed the new fan clutch and went out for a 20 min drive. It was about 85 outside and the temp gauge stayed at around 185 the whole time. When I got back checked with the laser temp checker and the tstat housing was 177, radiator plastic inlet was 160, radiator outlet was 120 at the bottom. Let it idle in the garage for a few minutes and it didnt get any hotter. The air dam plastic is off and some of the foam missing. I think its ready for a canyon run on Mulholland over to Malibu. When I first started it noticed more air blowing out from the fan with the hood up and when I shut it off the fan stopped right away less than a second
Forget the 'Like' farcebook thing.....Thanks for saying thanks! Makes us want to help MORE in the future.
As we say in Engineering..."Running Nominal"
Cheers Unkahal
Ps....REALLY go after the foam around the radiator and over the core support...this really Helps...every MOLECULE of cool air NOT DRAWN thru the radiator is LOST to you....Make that fan and shroud WORK!
Also get the spoiler/air dam back on!
I used the recommendations here and gave the Champion three row (CC1655) radiator a try.
A week after the install, I got underneath the car, and noticed that the lower radiator outlet was rubbing the sway bar.
This is unacceptable to me, as it will be a failure point in the future.
I swapped it out for a Dewitts HP (1149070A ), and am quite pleased on the fit.
Points noted are:
That the radiator fits better in the saddles, and does not have to be shimmed.
The overflow tube diameter matches OEM, and does not need a clamp.
The shrouds fit tighter to the radiator, improving efficiency
and there is plenty of clearance for the sway bar.
Also noted is that the thicker Dewitts radiator required more disassembly to get it to fit.
The AC compressor and alternator had to be moved for more clearance.
The slight difference in width makes a big difference in the install.
Fitting the shroud is the worst part of the job.
The Champion radiator is the one with the polished finish, the Dewitts has the satin finish.
Hope this helps those looking for a replacement for their 69-72 Small Block
I just finished my ls swap and I found that using a c5 vette fan and radiator was a good choice. After going on a buying spree in search of a pressurized surge tank I found that a Chevy cruise surge tank works great. This fall I might replace the cruze tank with an early c3 surge tank for more capacity.
I bought a COLD CASE for the 82 CE....other than having to switch to big block upper keepers and the ultimate fact that it's 40% larger than I took out....went well but it went in tight.
This thread was sapossed to provide a place to discuss cooling issues with moderator supervision to control redundancy and controversy. What it has turned into is a DeWitts Alternative report page. I am open to sharing my twenty years of Corvette cooling experience with anyone that has questions.
Tom, I have an odd question or two bouncing around in my head, and you're the only guy I "know" that might be able to offer up some thoughts or numbers. The story:
I have one of your radiators in my '69 (and in my turbo C4). They are high quality pieces that do their cooling jobs very well. No complaints. I have been putting my '69 on a diet for several years to keep it "competitive" with later Corvettes at track days (road courses). It's been my experience that even on very hot track days, I have more radiator capacity than I need, and possibly this would be an area that could be included in my weight reduction efforts. I'm looking at some OEM radiators (to keep the cost down in case this experiment is a colossal failure) that might fit the '69, and allow a bit of material weight reduction and water volume/weight reduction (this weight would obviously come off ahead of the front axle, the most efficient place to remove weight).
My question relates to the pressure drop across the core due to the water pump circulating the coolant. My two row DeWitts radiator obviously has some decent cross sectional area for the coolant to flow through, but I have no clue what that pressure drop is at higher RPMs at the track (it appears to be easy enough to fab some pieces at the inlet/outlet hoses to hook to a differential pressure gauge). If I install a slightly smaller cross sectional area radiator I would expect that there would be more restriction and a higher pressure drop from inlet to outlet. There's obviously the static pressure in the radiator due to the heating/expansion of the coolant, and I'm just trying to figure out what sort of additional pressure/stress I'm potentially adding to the smaller/lighter tracktime radiator.
I'm still trying to get things sorted out in my head here, but if you have some technical/engineering thoughts on this modification/experiment, I'd appreciate your input.
Thanks,
Mike
Edit: Just looking at a spare thermostat it looks like that is probably the biggest bottleneck in the coolant loop. I can measure/calculate the cross sectional area of the radiator hoses easily enough, and I can probably SWAG it on the radiator by making some guesstimates of the internal area of each tube, times the number of tubes.
I'm installing a Champion AE478 in my car today (06/29/2019)... and retaining the OEM shroud.
It's an inexpensive option and looks very nicely built plus has the 1" cross/core tubes.
So far , so good, but it's not a direct "drop in" replacement as insinuated... side tanks are shaped differently (than the original style
with radius-ed corners) and thus doesn't fit in the saddle mounts just right.
Also fittings for the transmission cooler are different and use and o-ring seal in conjunction with the inverted flare fitting...
It's gonna take a bit of fine tuning to make me comfortable with it.
More details to follow as I continue.
mardyn
btw: agree with the above comments about removing the core support... I did it the other (hard) way and it's kicking my butt.
02-22-2019, 06:07 PM
My LT-1 still has weird cooling issue...
