Can't help you there I've taken out the A/C so I mounted the cooler centrally in front of the rad, where the condenser used to be.

 

I've been contemplating a tranny cooler also to eliminate my similiar problem. I also didnt want to install it in front of the a/c condensor. I saw some ads for coolers that mount "remotely" , whatever that means, obviously somehwere other than the front of the rad/condensor. I just installed a 10 in flex a lite fan hooked up to the a/c , mounted it right in front of the mechanical fan , which I left in by the way. Just waiting for temps to warm up and the rain to finally stop to see if it works.
Photovette, I found your observations about the freewheeling fan at highway speeds to be absolutley correct, I can actually "hear" mine shut down, never to re-engage again till I slow down. One would think then that based on this assumption a fixed type fan would eliminate this problem. Has anybody tried this and did it work?
ESU

 

Well after trying to drive in the middle of an Arizona afternoon I've come to the conclusion that my Vette is a California Vette for a reason. It just can't take this heat, it creeped up over 230 and I just pulled over to a gas station and waited for it to cool off. It was like 110 degrees out as it was. The closer to San Diego we get, the cooler it's going to run so I'm not too worried about the drive back tonight.

 

It's the carb.........

 

You want to tell that to lars? He's the one that tuned it.

 

So Lars is perfect? Did Lars take your car on the freeway after he tuned it? Many carbs have to be retuned depending on driving conditions. He tuned yours at idle, and probably a hard throttle or two. I'm suggesting that you may be running lean in the high speed range.....

I'm just trying to help ya man.........I spent many hours chasing the overheating demons.

Pull your plugs and check them. You done that yet? Let me know what you find.......

 

Yes, I tried a fixed fan--not a flex fan mind you, but a nice solid race fan. It helped a little, but then it overheated in town. A Dewitts aluminum radiator is the solution. Though I do plan on having my carb tuned--I run an Edelbrock 1903 Quadrajet and I hear they run lean--anybody else hear that?

 

I've got a new Dewitts Rad.......that wasn't the answer, nor was the 160* t'sat, or all the other stuff. Reduced timing and proper jetting/rodding of the carb was the answer!!

 

Lars told me that edelbrock carbs are definitely lean, they are california emissions legal, I think that says it all.
ESU

 

 

No thermostat...HMMM....

 

I have a thermo clutch fan...comes on based on underhood temps..even at 65 mph at times...desert runs in 100 F+ uphill temps at 205....with A/C little higher...never over 210...
Rich

 

Over here in Thailand the temps are over 95 degrees 10 months a year. The other two months it drops down to 85. I have the original radiator and AC condenser plus a stainless flex fan with 180 thermostat. The engine never gets over 190 in city stop and little go plus highway driving at 90mph. I did have problems with engine temps when highway driving so I installed an engine oil cooler that took care of that problem. The biggest problem was in city driving the AC condenser would not cool with the flex and stock electric fax behind the radiator. The symptom was not only loss of cool air but the compressor would bind up causing the engine to try to stall. After struggling with this for over a year I finally had to add two more fans in front of the condenser that run when ever the AC in on. I really did not want to do this as now my hood doesn’t open very much but it does help in city driving.

My oil cooler

 

Kalway, believe it or not, we get some warm days here A couple of years back there was a high of 100F & I tried out the cooling system. After much effort I managed to get the coolant up to nearly 200F. I'm sold on trans coolers! As well as solving the hot coolant problem, it also does it's primary job of keeping trans fluid temps down, hopefully extending the life of the trans. Go out and fit one, you know it makes sense!
An oil cooler like Dean (hi ) has fitted is another good way of reducing temps as it's doing exactly the same as a trans cooler, in that it's dumping excess heat (don't fit one without a t/stat).
Lean mixtures at cruising speeds DO cause an engine to run hot. No offense to Lars (grovel!!!), but you could have a small vac leak/whatever that's leaning it out? Personally I think it's more likely to be down to the borderline cooling system. Mine was getting hot even though I knew that the system was in near perfect condition (& mine didn't have the extra heat problems associated with the aircon system).

 

Just got back to good ole San Diego! (OMG I'M GLAD TO BE BACK TOO!!!!!!)

Well here's the results, going through the AZ desert I couldn't go much above 65, otherwise it'd creep over 220*. Going up the steep mountains on the east side it got pretty damn hot and I had to pull over just before In-ko-pah park and just let it idle for a little bit to cool down. It cooled back down to 220 in a minute or two and I went on. After that I was in the 4000+ elevation and it was cooler and there wasn't much more mountain climbing to do. It stayed cool for the rest of the trip. After I got past Jacumba it stayed between 175 and 200. On the downhills it got down to 160. Bottom of the mountain, it stayed around 180 degrees all the way home. Granted this is like after midnight so there's no sun beating the crap out of it.

Basically it ran cooler, mostly, driving back to SD than it did on the way out to Tucson and I was able to maintain higher speeds, again mostly. Only hiccup was that little bit on the mountain where i had to pull over for a few minutes and let it cool off. I richened up the primary metering rods one step (47 from 48) and put in a thermostat. I checked the radiator for any grime and nasty stuff and it was pretty damn clean, amazingly. I also made sure there weren't any vacuum leaks before I left.

I may have to drive back out there again next month so I'm going to get a new radiator before then. Any suggestions for a low cost radiator that will cool more effectively? I've heard some of the universal aluminum radiators will fit C3s without any mods needed, and they're like $200. However I can also get a 4 row regular direct fit for about $140 locally.

When I have more time available I'll eventually try oil and trans coolers. Need to change the fluids in both now, after that trip. I also want to reinstall the A/C sometime in the near future so I'll have to see what I can do about fitting a trans cooler. I think an OD will help these long trips much more than anything else, though.

 

Did you have any of the symptoms of lean condition, i.e., surging at cruise or anything else?


I'm trying this for extra airflow through the radiator--you guys thinks its maybe too Rice?

 

No, it ran very smooth, but the temps would keep running up If I attempted to run over 65 mph.........That's why it took me a while to figure it out. Finally pulled a few plugs, and they were white. Barely even look used. Rejetted/rodded and bingo..........could run all day at 80 mph and never get over 205*.

 

Yeah, that looks too rice. Another option would be to remove the p.side t-top and use some Duck tape to fix it to the top of the p. seat so that it sticks up in the air. It'd get great airflow direct from a high pressure area & it wouldn't look rice. Additionally, it would prevent you having passengers (unless they kneel on the p.side floorpan) which would reduce overall sprung weight

 

Dewitts cooling.pdf....

http://www.dewitts.com/download/cooling.pdf

 

According to that, looks like the radiator. Now would an '81 with A/C have a 3 row or 4 row radiator? I'm guessing 3 row, because big blocks had 4 rows.