I have a SBF 302, with a new 66 OE mustang 3 row rad, electric fan and shroud, 50/50 mix of antifreeze and water. A couple of weeks ago the outside temp was 60 and I drove the truck city/highway for an hour with my gauge hovering steady at 180 or less, the fan never had to come on. This past weekend the outside temp went into the low 80's, again drove the same route, and I had to manually switch on the fan and also the in-cab heater to keep the gauge reading 180-190, otherwise it would have gone 210+ for sure. I have a 16lb rad cap that came with the older rad of same setup, and not sure of the thermostat. I looked for that rad and it said 13lb was suitable, and was thinking 180 for the thermostat. Do you think the 13lb rad cap and 180 thermostat are the proper settings along possibly with water wetter will ***ist with the summer weather?
What brand electric fan and how big ? Post some pictures of everything so we can see better what you have, including the grille opening. Don
Is the fan in a shroud that pulls air through most of the radiator? It seems that you don't have enough radiator or air flow through it.
Thermostat only controls when it opens to help with warm up - but once it's open it doesn't matter any more. I think we need to see a bit more - Radiator, Fan, Zgrille opening, Shroud to make any educated guesses.
The lower rad hose doesn't have a spring inside, but it is only like 8" long, I wouldn't think it would collapse would it? The other thing is that last summer with essentially the same setup, with exception to the stainless perforated hood sides and the dual snorkel air cleaner from an open air element, the temperature gauge was in an acceptable range. That is why I thought maybe the rad cap could be changed and possibly the thermostat was stuck.
When the fan is on, I can feel the air being pushed to the firewall, so I would say its correctly working.
I'm not a big fan of Mustang radiators. In '65 and '66, they barely cooled a stock 289. Add A/C and they didn't cool at all. Ford corrected this problem in '67 or '68 but they don't retro fit in the '65 and '66. Interesting article on the U.S. Radiator web site http://www.usradiator.com/news/car-warriors-66-mustang/ I had a problem with a '52 Chevy I bought, mild custom. It ran at 180 unless I ran into traffic. Then it would go to 210. When traffic moved, no matter how fast I went, it stayed at 210. Since I was adding A/C, I didn't hold back on a radiator. I bought one of their Desert Coolers, 4 row, triple p***, copper/br*** radiators as a direct fit and used a 160 thermostat. The car ran at 180 until I checked the timing. The vacuum advance was frozen so it was always retarded. Popped in a new distributor and the car ran at 160. !80 with the A/C on in traffic on a hot day.
ok I have a wimpy rad, but it was wimpy last summer too and weathered the storm so to speak. Still wondering what rad cap and thermostat I should use with that setup.
180° on the thermostat is fine, if it's a good one. The higher cap will allow higher temperatures before it blows off and spews fluid. 12-13lb. should be about right, but the 16lb will it make it run hotter by any means
I wouldn't worry about the stat & cap. You need a higher capacity fan if that's only a 1500CFM. Can get them up to 2700CFM i believe. Also make sure your timing is right & your not running lean. Butch
Those Hayden fans are junk, I was going through one a year when I was using them. Then I switched to SPAL and they not only blow 3 times as hard, but they last forever. They cost a few bucks more up front but are cheaper in the long run. Also, as Butch said, check the timing. SBF's like a little more advance to run right and cool. Don
dbucher, cooling issues are usually caused by insufficiant air or coolant flow. As others said, timing or a lean condition can cause overheating too, along with insufficiant lubrication of course, (God forbid) but more often than not, it's a lack of good air or coolant flow. You've got a good new radiator, and I imagine your water-pump and thermostat are probably fine, so coolant-flow is probably good. Dana brought up a good point though about the lower rad hose possibly collapsing. There should always be a spring, even for an 8" long hose...it may have softened up enough to collapse since last year. Run the engine to bring up the temp. Now rev the engine while viewing the lower hose. If it's collapsing, you'll see it at the higher rpms. If the hose isn't collapsing, pull the rad cap, (after it's cooled some...be careful) and with the engine running, view down through the filler-neck. When the engine is above the temp that the thermostat opens, you should see obvious coolant turbulence...it should flow like a river. If you don't see that, your thermostat may very-well-be stuck closed. I addressed all these possibilities just to cover our bases...you know, process of elimination. Now...what I think may be the real problem. You said the car ran cooler last year, so Engine man is right to have you think about the changes you made since...specifically, your new hood-sides. They don't look too restrictive, but it may be deceiving. I think that maybe the hood-sides and your shroud and fan may be working together to restrict air-flow. You've got a full shroud, which is tight to the radiator...which seems like a good thing to have. But it's flat and shallow, with no angled sides, so no ventury-action at all...lots of turbulence, but not good flow. In addition to that, you've got a fan that's heavily grilled, which actually makes the fan a source of restriction too...especially when it's not running. And as was also said, a 1,500cfm fan might not be up to the job...especially considering the enclosed rad. You're depending almost totally on the fan to move the air. Remove the shroud and fan. Your gonna flow a whole bunch more air at speed without it...even when the fan is running. If the egine runs cooler without it, you've found your problem. Of course, you can't very well run in traffic or sit and idle with no fan, so either get the most powerful fan you can buy, (maybe a SPAL as Don mentioned) or try running a fan without the shroud. And you might consider removing the hood-sides too. Good luck. Let us know how it works out.
Ok, thanks for all the informative responses, I will go through the list of things to try, 1 at a time and review the results
Thats a good lookin truck.... Keep in mind to cool of a thermostat could cause over heating as well. If thats a newer 302 you may want a 190. I personally would think 180 is fine, but keep in mind the theory behind what I am saying is, if the thermo opens, then the coolant flows, if it doesnt spend enough time in the radiator, caused by thermo closing, then the engine in time, raise both the its temp and the radiators temp.
I did the diamond plate for the shroud. The fan is bolted onto the shroud as is the overflow canister, not much room there. There is 1/4" space between the fan and the rad. The previous owner had the fan screwed right through the rad, and over time punctured the cooling fins and leaking, so I s****ped the rad and replaced it with the same from scott drake's. With the 32 grill shell I didnt have a lot of options within the certain budget. The truck creeps up in temp when stop and go traffic, runs better on highway. I checked the overflow canister and it is bone dry. I will add a couple of inches of coolant to it and drop back to a 13lb cap which that rad is rated for. I just re-used the 16lb cap from the old rad, but should have changed it then. I was originally thinking of going to a 160 t-stat, I don't know whats in the truck now but will be changing it anyways, but maybe from the comments should use a 180-190. the engine is a mid-70's, points ignition, timing seems good, truck runs great hi-way, gas is so **** though, have to be careful with pinging.
I am a big fan of water neck flow restricters,never have to worry about a thermostat issue,always ran the medium size one. This especially can be an issue if you're running something like a flowcooler water pump,won't let enough flow. Rule of thumb is the more radiator flow tubes you have the more air has to go through it. If you have a slow speed cooling issue look for air flow and if doesn't cool down at highway speeds look at coolant flow. I used to work in a body shop and remember looking at a 93-97 Camaro fan shroud and they had rubber flaps at the bottom to let air out as your speed increases instead of a possible air cavitation issue,noticing how tight and shallow your shroud is. Hey I'd even look at that distributor and make sure those advance plates and advance canister are not sticking or leaking.
Pinging/pre-ignition? Definitely check the timing first. All that I suggested about the fan and shroud may still hold true, but if you have pre-ignition, that just compounds the problem. You also mentioned that the overflow can was dry. That leads me to think you may have a small leak. If it's small, it's probably evaporating off quickly due to the engine-heat, so you never saw any indication of it. The water pump might be leaking from the little hole under the snout. That happens when the bearing goes bad. Remove the belt, and see if the input shaft has even the slightest bit of play in it. If it does, replace the pump. Again, you may have multiple "small" problems working together to cause the overheating. Your fan and shroud setup might actually be working well enough, as long as there aren't additonal problems.
If it worked last year, I'd guess bad thermo or fan control is not turning the fan on at the correct temp.
I've read up to post #20. Junk that flow-blocking shroud setup; the rad. should be naked on the highway. Cushion around the fan to the radiator with rubber. Triple row radiators flow less air and oftentimes less coolant than single row. Aluminum outperforms copper-br*** in shedding heat to the air. In short, if your Mustang radiator is both of the above, sell it to someone who doesn't know any better. The 13lb will let it boil over easier and not improve a thing. A 16 will raise boiling point and not hurt a thing. Run an air-dam under the radiator area. Air more easily flows under a car than through a radiator. (Yes, I know to the sides in your case is an easy path too.) Thermostats set minimum temperature. That's it. Lower temp ones DO NOT improve cooling. Robertshaw "high-flow" stats are junk and don't open at their rated temp. BTDT, with DD, with a gas tow vehicle and others. I run a Delco 195 stat. In Phoenix. In the summer. Up hill. In a black car. Without AC. Yes, it will be over 120F here this year.
Like Rickybop suggested after all is eliminated with the possibility of any coolant issues,try running without the shroud and see if that may be hindering your air flow. If that seems to be an issue,you might could trying putting a few 1" holes in it and see if that may help,letting some hot air out. Remember for every tube the radiator has,takes that much more air to go through it and draw the heat off it, especially at low speeds. You know if you've restricted the air flow just enough, you may be heating up that last of the three tubes on the fan side of the radiator. That shroud looks pretty good,you may or may not want to consider that. Good luck and keep us posted,always like to find solutions !!!
great suggestions by all, this site is very helpful. I will start with the low hanging fruit issues, as removing that shroud is a pain in the ***, at least putting it on was. Unfortunately it will be a week until I can get around to the corrections, will keep you posted
Finally an update. Needed warmer weather to test things out, as before outside temp was only around 60-80, last week and for the next several days coming, its over 100, so I got what I needed all right. So simple things first, I made sure my puke tank was working correctly, then changed the thermostat, and replaced the rad cap to what was required by the rad. All these didn't do anything but were good to inspect or replace anyways as were cheap. I think the fan that came with the truck was more suited for a 4 banger as it just didnt have enough power. I went with a Mr. Gasket 1800 cfm. I then opened up the top of the shroud a bit to let some more airflow. I then drove it through city stop and go traffic, and was getting a little nervous when I kept watching the temp. creep up to 190, then 195 approx. and then it stabilized. Then did a run on the highway and still no movement past 195 approx., so I am pretty happy at this point. Ok, now I don't need the hot weather anymore so can someone turn it back down. Thanks again to all who ***isted with their time and knowledge.
That's a pretty nice result. Flush that system for new distilled / coolant each year or use additive yearly to prevent buildup. I'll be sure and turn the heat down tomorrow for you.
The Jalopy Journal
