I don't have AC so maybe I won't have to trim the latch support, I see how you did it. Did you use a attachment kit to install the fans and how did you do the connections to control when the fans come on? Sorry for all of the questions but I want this to look right.
I hope the fans solve your problem, but I have serious doubts that they will. Less than 2 minutes with a timing light will confirm your timing at idle. I suspect your problem is timing related or a clogged radiator, or both. Fans will not help. Good ones that actually do something consume a lot of amperage, so I hope you are also upgrading your alternator to keep up. If you plan to wire in a manual switch, use a relay. If you want them to come on automatically, you'll need a temperature sender and relay kit. https://www.painlessperformance.com/wc/30101
Larry, thanks for sending the link. I will check the timing, vacuum advance and radiator flow like you suggested. I haven't been able to get to the car to do much of anything lately but maybe get to it this weekend. Good information.
Checking the timing costs you nothing in time or money. Find a manifold source of vacuum on the carburetor or intake manifold. Hook the vacuum advance to it directly. If the vacuum advance is working, the engine idle should speed up. Lower the idle speed with the idle speed screw. Drive the car and see if it runs cooler. That should take you all of 5 minutes and cost you nothing.
I can't remember for sure, but I think I used a mounting kit from Flexolite. It had heavy-duty metal tie-rods that went through the radiator, rather than plastic. I used two relays, and two toggle switches under the dash, so I can turn them on individually and whenever I want. I didn't want to have them turn on automatically when the a/c was turned on, because they aren't needed when a/c is on while going down the highway.
Ok thanks! I am going to follow Larry's suggestion and check the timing and vacuum to see what kind of improvement I am getting with all of that set properly. Good information here guys, I'll get back and update.
What is your ratio between antifreeze and water? Bad tune can certainly make the engine run hot, but I always start looking for a flow problem (either antifreeze or air) first. And on older cars, the first thing I look at is the lower radiator hose to see if it's collapsing from the suction. Then I look at things like thermostat, quality of the coolant, flow obstructions (either air or liquid), etc. Something surfactants (i.e. RMI-25 or Water Wetter) can help a bit with cooling, but if you have a drastic problem those aren't going to cure your ills. Also I see SO many people running undiluted antifreeze... I like around 25% antifreeze with some Water Wetter or RMI-25, with the balance being distilled water. If your clutch isn't engaging, that can be a huge issue too. I've seen a bunch of issues with fan clutches, and for a while (don't know if this is still the case) the "heavy duty" clutches were the only ones worth installing. I know this isn't the case for you but if you are overheating when your car is going more than 25MPH then you have a flow restriction of some kind, no fan will help. Fans are great to cool while idling and driving slowly, but on the highway fans don't do anything at all. A few years ago I calculated that while driving 55MPH, the average airflow across a radiator was something like 18,000 CFM - so a 2,000CFM fan (even if running) blocks more air than it pulls. -Bob C.
All good points Bob, but if you look at his first post, it seems he has plenty of radiator, and temperatures are not a problem once he is moving, just idling and stop and go. Not sure if he has a shroud or not.
For sure - but this sure smells like SOME kind of a flow issue to me which is why I rambled on a lot of topics. The OP is going to have to do some detective work on this, and the more points to consider & better the understanding of a cooling system the better. A mechanical fan with a 3-core radiator should give more than ample cooling for a 300. Having said that, I have installed a pusher fan (in addition to electric pullers) to really get the air flowing across the radiator. I intentionally offset the pusher fan from the two pullers so that airflow velocity was higher over more of the radiator's surface area, as well as to help give a "boost" to the airflow. I'd be looking at the fan clutch first, I've seen so many of them fail. But also if he is running a 160 degree t-stat, it's possible that even a correctly-functioning clutch won't engage at those low temperatures. (Honestly whenever I have the option I remove a clutch altogether - the t-stat does a fine job of controlling temperatures and having two temperature-control devices is unnecessarily redundant IMO, not to mention just gives another possible failure point). -Bob C.
A lot of these eara GM cars have this issue and it's due to huge gaps around the perimeter of the fan shroud if the car even has one thats more then 200 degrees in circumference. The root of the whole problem is that at idle it's easier for the fan to draw in air from the leaky perimeter of the shroud then suck the air through the radiator and in cases like this added another row to the radiator does not help the situation much if any! Also many of these stock set ups do not loacate the blades of the fan half in and half out of whatever shroud the car does have, in other words the fan sitting too close to the radiator will cut down on the air getting pulled into the radiator.
Bob, I bought a vacuum gauge and dug out my timing light. Adjusted the carb idle to specs and advanced the timing a bit and got the vacuum where it should be, engine is happy and throttle response was good. Let the car idle in the garage for a half hour, drove it a little between the thunderstorms here in KC, let it idle again in the garage and it never got over 18o degrees. However, it has not been very hot here and I have not had a chance to take the car out on the highway. Plus I want to go through and check everything again, just haven't had a chance to get out in the garage and do it. Supposed to be nice this weekend and I'll get a chance to work on it some more. Looks promising though. I'll also post some pictures of my fan and shroud set up. I did put a thermo fan clutch and 6 blade fan on it replacing the old original 4 blade fan the car came with. All good advice here. Thanks!
