vanti II, 350 sbc 300 hp Our A/C was refurbished last fall and now blows plenty of cold air. However, when we need it most - in bumper to bumper traffic and 90+ degrees heat - the engine starts to quickly overheat. We do not get overheating if the A/C is switched off. I just posted a pic of the engine bay in the Photo section under RQB 3496. There is a round puller electric fan mounted directly on a new radiator running off both a thermostat and energized A/C compressor circuit. I am thinking of getting a two-fan electric set up with a shroud so that air is pulled through more of the radiator surface. http://www.flex-a-lite.com/auto/html/twin-line-fans.html Before spended a few hundred dollars chasing a pipe dream, I was hoping to get some feedback from those that have been here before. Thank you, Joe and Judy Menacker RQB 3496 ---------------- Joe; I've been there before! Flex-o-lite is just down the road from me and I've visited their plant. They make good stuff. I'd recommend you upgrade as your thinking. Either a larger fan or the two unit setup to pull more air through more of the whole radiator surface. In most cars, I don't think a pusher fan (mounted on the far side of the radiator) does much good, but on the Avanti, I think it helps draw air up and through. So you could consider adding a pusher fan. Also, do you have an air dam under the radiator? I realize this is most helpful when the car is moving, but it also helps when the car is still by creating a barrier, which in turn creates a draft effect - or so I've been told by more than one shop. One other word of caution - not to alarm you but just so you know it CAN happen. Years ago in my Audi V8Q, I installed a new radiator. Either it was defective or some sludge from the engine got into it and plugged up part of it. For the longest time I refused to believe my problem could be the radiator. But a local shop had an infrared temperature gun and showed me how the temp at various locations within the radiator varied considerably. It didn't cost me anything for them to use that temperature gun. It might not be a waste of you time to have this done on your "new" radiator - just to ensure you're getting good flow throughout it. Good luck, Richard Richard Morris Renton, WA 1964 Avanti R-1 #5367 1990 Avanti 4-door #78 ---------------- Joe, FWIW I would sugguest installing A Failsafe Thermostat 7200-180, if the engine overheats the thermostate will lock in the open posistion not closed, you can get it at AutoZone auto parts. What deg thermostate do you have in? you did not say if you had a front air dam, this will push a little more air at low speeds. Your engine compartment looks great! what air cleaner do you have on the engine? Rone502 RQB 2809 ------------------- Richard: Thanks for the tip about the infra red gun. I have had some suspicion that the radiator is not working as well as it should. The fan is pulling a good deal of air and the incoming air really only has one route in - from outside the engine compartment. A quick check of the radiator surface vs. round fan surface reveals that almost half of the radiator does not have a fan pulling air through at idle. We will probably add the air dam as you and Rone suggest. It can't hurt (unless the car falls down on me while I'm under there), and it should help at low speeds to jam a bit more fresh air through the rad. Best regards, Joe and Judy Menacker RQB 3496 --------------------- Joe Two things may help. Living in Canada I was always concerned about freezing so had my anti-freeze mixture for -40C. This in the summer is not good. Ck your mixture and I would rec. a 50-50 mix or even less anti-freeze. I also have just this year used some Redline water wetter and in my opinion it did have a significant effect on the running temp. I wonder about the shroud. I can see were it directs the air coming thru the rad but it also limits the total air flow because it forces the air against the front face of the engine block. With it off (thats how I run mine right now) there is more area for the air to flow into the engine compartment and exhaust down and out (or into the interior if you haven't sealed properly. With the 90F summer that we have been having in the Toronto area my R2 with A/C is running about 175-180F with a 165 stat. Cheers Jim 63 R2 4sp with A/C -------------------- I think the t'stat is a 190 degree model but it has not yet been checked for proper operation. The car is fine without the A/C on and it doesn't overheat while moving better than 25 mph. Air dam is a damn good idea, we'll do it. There is a round drop type pancake air filter on the carb. I'll take a pic when I get home tonight and post here. Best regards, Joe and Judy Menacker RQB 3496 -------------------- joe, Does it have a thermostatic mechanical fan still? Those sometimes lose their ability to lock up-it typically shows up when you are stopped in traffic. My 82 II with the stock 305 and just the stock mechanical fan can sit in traffic with the A/C on here in Wash D.C. and only go up to 215-220F on the gauge. It always amazes me that with the limited intake area that it doesn't overheat. I did recore the radiator several years ago but it is just the stock configuration too. I would recommend getting your mechanical fan checked (if it still has one). chuck RQB-3553 ------------------- Chuck: The pulley fan is gone. I believe that the original set up had a cowl behind the radiator. I suspect that if there was a cowl there, then previously the radiator had more air flow and could exchange more heat at idle. Joe M -------------------- Joe... There's a couple of things to look for. If you still have the original fan installed, make sure the fan clutch still works properly. It should lock up when additional cooling is needed, such as low rpm cruising when there is little air flow through the radiator. It de-clutches when not needed such as at higher speeds and doing so, it saves horsepower. If the fan clutch is working properly, it should stop almost immediately with the engine when shutting it off. If the fan continues to spin, the clutch needs replacing since it's not locking up. As someone else said, there could be a restriction in the radiator. I know you have a nearly new engine, so it's not likely you have a restriction in the block's cooling passages. The radiator core could need replacement. If so, go to a radiator shop that can build you a radiator the same size dimensionally, but with increased fins per inch. A Dodge Charger I owned several years ago was overheating, and I had the radiator re-cored with the same size core, but it had 18 fins per inch instead of the original 12 fins per inch. That gave it much more cooling surface than the original core and made a real difference. Avanti's all need whatever help they can in the cooling department. You should have the fan shroud in place as well. It helps draw the air through the radiator more efficiently. When you find the problem and correct it, you can add a bottle of "Water Wetter" to it. It coats the interior metals of the cooling passages to make them shed heat better. Places like Pep Boys carry it and it costs less than $10 for a bottle. Hope you find the problem quickly so you can enjoy the car more! Bruce Blum Frederick, MD ---------------------- Joe and Judy, Just would like to pass on my experience with trying to make the Avanti run cooler. Its a 1978 with the 350. In the summer in Tennessee, it would run about 205 degrees. Not a degree more, never overheated, but it seemed pretty warm to me. I put in a 165 degree thermostat, that made it run cooler when first started, but eventually it would get back to 205. Next was the Saturn air dam. That actually made a difference, it cooled it down to maybe 200 or so on the road. Next was replacing the clutch fan with a hot rod type flex fan. That made an additional difference of five degrees or so. The biggest improvement came from pulling the radiator and having a local shop that does a lot of street rod and such work made a new radiator for me. Now it runs at about 180 in traffic or on the highway. Much better, its about a 20 degree improvement. I was going to try and install a oil cooler, but now I don't think it will be necessary. I did put the truck oil filter on the car which is slightly larger than the standard one. A little more oil may make a difference, I'm not sure on that one yet. Just look up in oil filter book for the same year Chevy or GMC truck with the same size engine. So for what its worth, the best bang for the buck was the flex fan. Good luck on your progress. Bill C. RQB2677 ------------------ I have a 1990 Avanti 4-door, vin #1037 and the AC evaporator is leaking. Can anyone tell me the source of the evaporator (or part #) and the best way to remove it from under the dash? Ron Garvin Ph: 410 879-9026 rongarvin@aol.com ----------------- Joe and Judy, I also have an 82' and run a single 17" 3300cfm Zirgo fan for the "regular" cooling duties (no mechanical fan/shroud). In addition to this I have a 12" Hayden "pusher" in front blowing through the aux. trans. cooler (Hayden also) and condensor/rediator. This pusher is wired to a trinary switch on my receicer/drier that will turn it on when high side refrig. pressure exceeds 245 degrees f. My radiator appears stock to the untrained eye but was actually recored with a core that has 5/8" tube spacing as opposed to the stock 3/4". This allowed for approx. a 30 % increase in capacity (all 3 rows total) without an increase in size or thickness. Also, you mention that your AC system was "refurbished". As I still see the Frigidaire A-6 (large) compressor in place in your pics. I can only assume that what you mean by "refurbished" is "converted" to R-134a refrigerant via a changeout of oil and refrigerant. As I have noted in previous posts, the Vintage Air catalog and web site are an excellent resource and I will quote them here: "The GM/Frigidaire A-6 (long type) compressor shares the same basic design as the Sanden with one cylinder added. It has the same characteristics except that it is very large in both capacity and external dimensions. It is about 12.5 inches long and 5 inches in diameter, with over 12-cubic inches of displacement per revolution. We cover this compressor lightly because, in our opinion, the only place I would recommend using it would be in an extremely large sedan, with a high capacity evaporator, or two evaporators. A minimum of a 400 square inch double row, 5/16" copper and aluminum fin condenser would be necessary with HFC-134a provided airflow and temp. were good. Using the GM/A6 compressor has been a painful and costly experience for many street rodders." In other words, the A6 pumps a LOT of refrigerant which moves a LOT of heat along with it. Contrary to popular belief, R-134a is a MORE efficient heat transfer compound than R-12 which is why the systems/components MUST be sized properly. Your cooling system is probably working just fine but is being overloaded at idle due to the greater amount of heat being transferred to the cooling air at low speeds. If you did not do a real conversion (new parallel flow condenser and correctly sized compressor) you are causing your own problem. More airflow is the only thing that will cure your current setup's ills! If you are still running R-12 then I would look to the cooling system. My 12" pusher will kick on after about five minutes at idle (sitting in traffic) if the temp is above 90 degrees and then kick off after about 25 to 40 seconds. My 17" kicks on at 200 degrees (running a 195 degree thermostat year round) or when the compressor is running. I do have the Saturn air dam and want to remind everyone that its purpose is NOT to push air up into the nose but to create a low pressure area behind it (the dam) to draw hot air out of the engine compartment at speed. Yes, i'm sure that it does push some air up but that is NOT its purpose nor will it contribute much (if anything) to low speed operation/cooling. Tom Gorr RQB-3449 -------------------- Aug 2005 Cooling Solved First the electric cooling fan was switched from a puller to a pusher without much improvement. Then the radiator was changed from three row 5/8" spacing core to three row 3/8" spacing. The higher exchange radiator kept temperatures below 215 F. Finally an engine driven high performance fan was added and the pusher fan hooked up to relay on only with the A/C compressor running. The addition of the engine driven fan now keeps temps down to 195 F max. We do not yet have a shroud installed. Summer is almost gone and we wanted to have fun with the car for a while before bad weather sets in. Since the Avanti has been in the shop quite often making adjustments we purchased a 1984 Euro BMW 635 with a five speed as a back up. The 635 was driven for a few weeks while the Avanti was in the shop. It is one beautiful car and handles with much grace and good sensual feedback. We started thinking that the Avanti would be mothballed. On Tuesday we went to pick up the Avanti. As we were paying the bill the car was brought outside the office and left idling to demonstate the cooling capacity of the new set up. All negative thoughts quickly disappeared when we hear those dual Magnaflows purring. The BMW 635 is certainly a a very nicely balanced car that attracts attention. However, the Avanti is overwhelmingly more seductive with its unique lines and eight cylinders growling to motivate a car forward. Thanks to all who support this board and the Avanti. We never would have suspected that the reconditioned radiator installed in the motor swap would have been part of the overheating problem. It just goes to show that one should never assume. Regards, Joe and Judy Menacker RQB 3496