Joined: Wed Aug 25 2010, 02:04PM
Location: Upstate NY
Posts: 78
I have owned my 68 300 vertible for 8 years or so and I have not found a fool proof way of staying cool on hot days and mainly in stop and go traffic. Highway is fine but I can’t keep the mainly factory setup running below 200 degrees. Forget numbers matching or aesthetic looking, if I could hire one of the seven dwarves to hold iced compresses to my engine I’m willing to pay.
My engine was completely rebuilt, flushed and tanked with new everything about 4 years ago. About 7k since. New 3 core, I think around a 180 thermostat. New clutch fan with factory shroud. Recovery tank as a radiator overflow. And now I’m running a pusher fan on a temp switch and it’s stying a bit cooler but in stop and go it just climbs to the 210-220 range which is just to high. It will sometimes stall and then the starter (mini high torque) will not engage until it cools down after 15-30 minutes. If I get it going on an open road it goes right back down to 190 in just a few minutes.
Forget cost for a second. Has anyone found a way to successfully address this and if so, please tell me what you used and how you set it up.
Joined: Tue Oct 11 2005, 01:33AM
Location: Calgary, Alberta
Posts: 5893
Interesting. I assume you have AC with a 26" rad, shroud and flex fan.
My Fury has no AC so it's got a 22" rad with a steel 7 blade fan. For it's first 50,000 miles it spent many hours in traffic jams and even on stinking hot days it never boiled over. During the car's overall restoration, the rad was rebuilt. Ever since I've had heat problems, slow trips it gets hot, stuck in traffic it boils over, highway cruising all is great. I'm about to have the rad redone, this time with a 4 layer core with cross feed. I'll also add a shroud if I can get one that will fit a 22" rad.
I think the factory rads were very well made with lots of copper and the replacement cores leave much to be desired. So now it time to go nuts and overbuild. LOL
Joined: Wed Nov 17 2010, 03:28PM
Location: florida
Posts: 1311
your temps are fine for a big block if thats what you have and even a small block.temps in stop and go will always climb.i had a big block running 250 in traffic on hot days.this is where you should worry.if your not using new school tech then you prob won't see a drop in temps to your liking.my iron headed 10.5 comp 440 runs under 200 on a 90 degree day sitting still but i have many mods to contribute to this.your car must be tuned properly from the start.if its running lean it will run hot.to get an idea ,i use a modern cross flow alum radiator which will improve the cooling immensely(there are stock look alikes available),no mechanical fan(no room),i have a 16" puller and a 10" pusher,full shroud,i run no thermostat here in florida ,i also have twin oil coolers for more oil capacity(@ 8 qt.) which i know helped me drop 20 degrees which is not a normal thing for most but my motor is @ 600hp.i have headers that are jet hot coated with a full 3" exhaust.exhaust manifolds hold heat.i use an aluminum water pump with high volume impeller.these may not be the things you want in your car so like i said 220 isn't too hot.my new challenger runs 210 and I've always seen old cars running anywhere between 200-220.i would start with the tune and possibly changing your coolant to one of the fancier ones that can also drop your temps.
Joined: Tue Oct 11 2005, 01:33AM
Location: Calgary, Alberta
Posts: 5893
My engine is nothing fancy, a more or less standard 350 hp 440. The tuning has been looked at but could I suppose be revisited. Calgary is pretty high which makes tuning most important. My rad is only 2 rows with no cross feed. I feel that is where I'll make the most progress by going 4 row crossfeed using copper. I want to retain the "factory" look so pusher and puller fans are not an option.
Joined: Sat Aug 19 2006, 05:03PM
Location: Ontario, Canada
Posts: 2919
limabee: What water pump is installed in your engine? Do you have a factory cast iron or aftermarket aluminum water pump housing? Are you sure that your fan clutch is engaging at an appropriate temperature? Have you confirmed that your thermostat is opening fully and at the correct temperature? Does your thermostat have a bleed hole to allow any air trapped under it to escape past it, to prevent it from forming a bubble under the thermostat? (For the record, I recommend against removing the thermostat altogether.)
Joined: Wed Aug 25 2010, 02:04PM
Location: Upstate NY
Posts: 78
I am using the factory cast housing and a new water pump. As I said, car runs great normally, just overheats on hot days in city traffic. I'm not concerned with a factory look. I'm looking for new age solution so cross flow works fine.
Any recommendations on cross flow radiators with fan combo's? If so, company, size etc. My car is an automatic so that would be a factor as I would not want to run a separate tranny oil cooler. I'm fine with upgrading my water pump if there is a solution there as well.
I want to be able to drive the car without the hassle on any given day. I'm not worried about showing it as I'm not a big show guy.
Joined: Sat Aug 19 2006, 05:03PM
Location: Ontario, Canada
Posts: 2919
OK it's a new water pump. What kind? I had the same problem as you. I had a 22" 3-core rad that had worked great with my old 383-2v but couldn't keep my 451 cool in stop-and-go traffic.
I installed an electric pusher fan as a band-aid, then a fan shroud. Neither really solved the problem. The root cause was the new-design "scroll" impeller pump that I used. It turns out that those don't flow well at low RPM. Mine was a CAT Performance one I think, but identical design to the Edelbrock one.
I replaced it with a Milodon high-flow pump with anti-cavitation plate. Milodon also recommended a high-flow thermostat in conjunction with this pump. I think I bought a Mr.Gasket 180* thermostat because it was cheaper than the Milodon thermostat but looked identical. Anyhow, that fixed my problems 100%.
Your problem could still be related to fan clutch or thermostat though, which is why I asked. You didn't comment on those items. You sound keen on throwing money at the problem. The root cause could be something simple but requires some diagnosis to find. Wouldn't it suck to spend big bucks on a new rad and then find out that the problem is that your thermostat is defective and not opening fully?
Joined: Wed Aug 25 2010, 02:04PM
Location: Upstate NY
Posts: 78
Thanks for the info Fury. I read through that whole thread.
So I have the old 68 housing (the one on the left which is smooth without the steps) and I believe an 8 blade impeller that gets <5 gpm. So likely my issues are coming from the impeller but what are your thoughts on replacing the factory housing? Looking at the 2 examples, it almost looks like the stepped housing directs the majority of the flow towards the impellers as an almost funnel while the stock housing looks like it simply opens into a lake within the housing.
I have a new stock 26 inch radiator. Brand new stock clutch and fan with the factory shroud. The front pusher didn't really have much of an effect. My current blah impeller is new but the housing like I said is factory.
I'm thinking of moving towards a new housing and impeller but I'd like to stay mechanical if possible. The thermostat is a 180 standard if i'm not mistaken.
This is not a drag car, but I would really like to be able to drive through a few traffic lights without having issues.
Hi Bill, I linked to that study here on a previous thread on water pumps. That's the study which showed that the Edelbrock-style impeller is not very good. I can't remember anymore if I swapped-out my water pump before or after finding this, but it confirms what I always say about them.
Limabee: If you have a stock housing now, I'd keep it and just swap pumps. First, I've never heard of anyone having problems caused by a stock housing, but I have with some aftermarket aluminum ones. Second, changing the pump is a pretty easy job and you'll know pretty quickly if it helps.
Wouldn't it suck to spend big bucks on a new rad and then find out that the problem is that your thermostat is defective and not opening fully?