Who much room do you have between the radiator and the water pump? If you have 2 5/8" you can run a Cooling Componets electic fan and shroud combo and it will provide all the air you need. I have a 54 Chevy that I have never had any cooling problems with. I have a 350/350 with a Walker Radiator.
I have had two Walker radiators that wouldn’t cool at idle. One I bought new and the other came with a project car. I replace them with aluminum radiators and the problem went away. Buddy Griffin (Griffin Radiators) showed me why to stay away from shiny pulleys. Chrome, belts easily slip and aluminum pulleys usually have one to one ratio. Make sure your water pump pulleys are 25 to 35% smaller than your crank pulley so you will overdrive the water pump.
I can't remember without rereading this whole thread; have you tried a stock type fan, instead of the flex fan? Not a four blade, but the larger type. The flex may be too weak and is flattening out too soon. I would have bet that the problem was air moving back around and recirculating through the radiator. But if you have tin work that prevents this, it is time to look elsewhere. Looking back at the pics of your shroud, it differs from a good OEM type shroud, in that it lacks the (for lack of a better term) the tunnel that usually surrounds the fan. I would feel around while it is idling to see if you can tell what the air is doing. It should not be batting the air out from the fan, only pushing it to the rear. If the fan is not surrounded by shroud it may be just throwing the air around. I always look to a comparable stock vehicle to see how the engineers handled the design. In the case of a vehicle like this one a pickup from the 80's or 90's with a V8 would be a good example, preferably one with A/C, as that adds in a lot of extra heat that needs to be dealt with. I totally agree with the assessment that you don't have enough fresh air moving across the radiator at an idle. You just need to figure out how to do that. ~Alden
Yeah. It's got a rigid blade fan in it right now. If I don't leave it idling for more than 5-10 minutes, it's no problem, depending on the temperature. In 80 degree weather, it will idle all day. Gotta get better airflow. The electric fan setup is probably best and I'm tired of screwing with this.
I would still swap out the pulleys to get the fan and water pump spinning faster. I dont even have a mechanical fan and it takes quite a while to get to 190 degrees to turn on the electric fan. My water pump pulley is smaller than the crank pulley as all my other factory GM style stuff.
I have a similar fan to that one linked sitting here ready to install, a Lincoln Mark VIII fan, supposedly between 3000-4000 CFM. My current single 16" spall probably is 1500 cfm or less. I cannot stand going from my daily driver 2010 Camaro and having the cooling system handle 440hp no problem, but the junk in my Merc can't handle a cammed sbc that probably makes 350hp. I think running traditional mechanical fans are just dandy if folks can make them work, but I need serious airflow. My car wasn't built to run that big of an engine stock, and once I go ever bigger the problem will be twice as bad. I say try an electric fan, single or dual setup. The fan i referenced earlier has a low and high speed and are used in cop cars that idle for hours.
If you dont mind the junk yard crawl, any chevy v8 or v6 shroud will work, if nothing else but to test seal up all the gaps around the shround with tape install the largest fan you can fit, ( you can mix blades on different clutches) some have longer or shorter shafts. I am running a summit radiator ( griffen ) and s-10 shroud and fan blade mounted on a fullsize chevy fan clutch it was the right shaft lenght to keep the fan in the shroud opening not to far forward or backward. Is there a chance you mounted the blades backwards on the fan clutch/shaft spacer? I know a fan from a sepentine set up turns backwards along with the water pump compared to the older setups. Godspeed MrC.
1. Check the timing. It's easy to check and shouldn't be underestimated. 2. Check the plugs too. make sure your not running lean. 3. Once this is done, move on to the radiator and the overflow bottle. Make sure both are significant for your application. I put a four core radiator in my old truck. Looks the same as the three core, only slightly thicker, and the old truck runs much cooler. 4. You already checked the thermostate, but double check it again. We sometimes get bad parts from these new autoparts stores we have now days. 5. Electric fans are nice, but I don't care for the extra wiring and relays. In my opinion flex fans aren't the best either. A stock fan with a clutch works just fine in most street applications. 6. Flushing everything out might not be a bad idea either. A blockage in the radiator or in the block can also be a cause for your overheating problem. 7. Check the oil for water and the water for oil. you never know, you might have a small leak in the head gasket. I hope this helps.
one of the things I don't believe you ever checked was a bad head gasket. if you run car without the rad cap on you aren't getting a flow of bubbles coming to the top of the system are you? other than that I would use a temp gun on the radiator and find how hot it is and where, from there I may add an electric pusher fan in that area to help out. Jesse
All of this has been done ad nauseum. I have ordered an electric fan and shroud setup from Cooling Components. Hopefully, I will put this issue to rest this weekend!
John, you gotta listen to your buddy and get a bigger, better radiator. I put a 160 thermostat in my '53 Chevy and switched it back out for a 180 because the car was only running at 160-170 on the highway. If you're at 190 and up on the highway with a 160 thermostat you need more radiator! The fan will definitely help, but a nice big heavy-duty radiator should solve your problem - there are plenty of mercs running around with high-hp motors that don't overheat all the time.
Thanks Atomic, I'm for sure doing a newer double pass 28x19 radiator (or in that ballpark). Plus the Mark VIII big single fan (as long as it fits). In the winter I saw 180 when it was 25F out.
Yeah, 180 when it's 25 degrees out is crazy! My '53 (that just barely cools enough at 100 degrees ambient temp) would not stay above 160 in the winter on the highway. It was kind of fun, though, to watch the gauge go up to 180-190 in stop and go traffic and then drop right back down to 160-170 when I got moving again. Now if only there were a way to pipe in cold air to the radiator when it's 105 degrees in August!
I might have seen 175 a few times, I was cruising in the winter out of boredom. If I can get my car to never go over 200F in the middle of summer I'm happy.
I'm running a 400 SBC( tend to run hot!) with a 2 core radiator out of a mistsubsi PU truck & a elec fan i cut out of some mid 90s buick with a 185o thermo & it doesn't vary more then 10o no matter what the temp is outside or what the traffic is! Theres something else wrong that being over looked. JimV
Hi Rockable, I would like to suggest a few things. I had this overheating problem and a friend helped me out. 1. Check the timing, 2, check that your carb is set right and is jetted properly. 3, check the thermostat , 4, Check the waterpump, 5, Check the radiator and cap. 6, check mixture in the radiator, 7, Turn the car off. Let the car cool all the way down. Remove the cap and start the car. let the car get warm with the cap off and watch for air bubbles at top of radiator that could be in the system. If and when bubbles stop turn off car let cool replace cap and start the car again and see if the temp is cooler. 8, Also some motor oils claim they can make your car run cooler. 9, some radiator additives claim to make your car run cooler by as much as 40 degrees. I am no expert but I hope this helps.
Master of the obvious and captain sarcastic.... lmao Of course there is something being overlooked or being eliminated prematurely or incorrectly. It should take about 1 hr to properly diagnose a simple overheating problem maybe three if its something really obscure and screwy. But since its all been done ad nausium, pointing them out its kind of like whipping a dead horse at this point. Start over with fresh eyes or scrap it and start over with a different motor.
Then you're gonna need a serious radiator! My car goes over 200 every time I stop in traffic when the ambient is 95 or higher, but it never goes over 220 and that's enough for me. (That's with a flex fan and shroud - if I had room for a mother-ass electric fan like you're planning to use I bet it would stay under 200 99% of the time.) I have a 3-row "high efficiency" core in my original radiator and it cooled my '53 just fine before I added A/C. And it's not even a cross-flow radiator: center inlet just like factory. Adding a small pusher electric fan in front of the A/C condenser made a surprising difference.
I had been fighting a similar problem a couple of weeeks ago. After replacing the water pump, T stat, and sensors that turn on the fans it still overheated. I pressure checked the coolong system and radiator by itself and all seemed fine. In my case it turned out to be a poorly flowing radiator due to partial blockage in the cooling tubes. I used a infrared heat gun and found that about 1/3 of the radiator was at 80 degrees (Dead smack in the middle of the core) even when the car was on the edge of overheating. New radiator, problem solved. I cut open the old radiator and found an excessive electolysis build up in the tubes where it would not get hot. The radiator looked like new when looking down the filler neck. Good Luck
True my late model was turning on low speed fan at 219F, though I just tuned it to come on sooner since the car would run 2 tenths slower at the track if you had to idle too long. I personally get like 90% of the stuff talked about but the only part I'm in the dark about is timing. I have a lot of late model LS experience with engines and tuning, but zero with SBC's. I don't really understand where base timing is supposed to be a with crate block SBC
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