Sorry to start another cooling thread, but......... I've followed the other threads and one of the things mentioned was to make sure the shroud was sealed against the radiator. Mine is sealed everywhere except for the top where I have it circled. Is that gap supposed to be there? If not, am I missing something? BTW, it's 70 Skylark w/ a 455. o No: TIA, baking :laugh:
I've never seen that gap there, but I don't have a 455 fan shroud. Kind of reminds me of someone cutting a hole in their 350 fan shroud since the 455 sits up higher... but I think thats too close to the radiator and support to have that be the case.
definitely not something from a 71 or 72 riv...or any big car. I don't believe I've ever seen that gap before.
This is a shroud from a '73 Riv, mounted with stock mounts in my '70 Skylark. Big gap from one side to the other.
It doesn't look like it's been cut or modified, if you look closely you can see a slot in the middle where it looks like a screw or bolt should go. Ya don't think that's a big enough cap to cause my car to run at 210 degrees do you? I've replaced T-stat, radiator cap, lower rad hose, flush and fill (btw no nasties in there, my rad looks brand new). I do have a 3 core and a five blade fan, according to http://www.buickperformance.com/runhot.htm those should be replaced w/a 7 blade fan and a 4 core.
What degree thermostat did you install? 190, 160, 185? THat can make a huge difference in what temp the motor runs at. Try installing a 160 and see if that lowers it at all.
Yeah, I put a 160 in. I haven't driven it since then, but idleing in my garage it climbed back up. I'm gonna duct tape the gap and take 'er for a spin, that should tell me if the shroud is the problem ( I hope)
I know I post a lot of info and I hope I'm not coming off as the self-styled King of EveryDarn Problem, but what exactly is the overheating issue, Brian? Depending on your radiator cap pressure, 210* F is not all that hot. I run that hot at 75 mph on the highway on a hot day in summer. At 30-40 mph I run at exactly 160*F, on a 100*F day or a 50*F day (I have a 160*F t-stat currently, but not for much longer) Coolant in a pressurised system will not boil at 212*F. Sometimes this gets overlooked. The system is kept at greater than atmospheric pressure because of the radiator cap, which raises the boiling point of the coolant beyond 212. The common rating is 15 psi, which according to my chassis manual, raises the boiling point to 247*F If you're running at 210*F in traffic, there's a problem, of course. I run a 160* t-stat in my 70 Skylark with a 455, and it's too cold- the engine isn't hot enough to run as efficiently as it should, plus the heater doesn't work as well as it might. That 160*F t-stat is the result of overkill in fixing an overheating problem. Can you describe the problem you're having, in detail?
The shop I bought my 4 core radiator from had the owner's '69 Chevelle in it. 396 cid, 4 speed, the works. Beautiful car, looked new. No fan shroud at ALL. I said to the owner, "you overheat with this thing?" He says, "Nah, it only runs 210" Yikes. ONLY 210!! I says, "Does it puke over when you stop?" He says, "sometimes". I said, "You still have the shroud?" The answer "Sure". I said, "oh"
It goes up to 210 and stays there. I haven't taken it out on the road since I put in the new Tstat, just Idled it because I'm also doin' the Zaino thing and don't want to drive it until I'm done polishing it (that stuff is amazing!). I suppose 210 isn't too hot but.....I don't want it to go higher, plus I hope to some day get headers. :laugh: Won't that raise the temp a few degrees? If so, I want to take care of the problem now. I've got a full day tomorrow, so it looks like Tuesday before I can road test it. Thanks for all the help, I'll post what happens after I drive it. baking
210 in every driving condition? That's not right. Do you have a mechanical or electric temperature gauge? By detailed, I mean: what type of temp gauge do you have? Stock electric? Aftermarket mechanical? what temp do you see while cruising around town? when you stop at a light? when on the highway? Does the radiator 'puke' or purge at a stop? What condition is the radiator in? What type of cooling system do you have? Including: # of cores in the radiator? (you have 3, if I remember) clutch fan? Straight fan? Viscous clutch, thermostatic? Do you have an overflow tank? How are the hoses, all of them? Will the lower radiator hose collapse if you rev the engine? Is the radiator cap in working order? This might be embarrassing, but everyone has probably done this once: is the t-stat in correctly, and is it working correctly? Do you have a sweet smell if you turn on the heat? is the water pump "weeping" at the bottom of the shaft? Any white or greenish residue around the pump? How old is it? They wore out when new Are the belts to the fan pulley the correct tension? Overheating is a drag, and worrying about your temp is almost as bad
210 in every driving condition? That's not right. Do you have a mechanical or electric temperature gauge? By detailed, I mean: what type of temp gauge do you have? Stock electric? Aftermarket mechanical? Aftermarket mechanical, I forget the brand. what temp do you see while cruising around town? 210 when you stop at a light? 210 when on the highway? 210 The only time it seems to change is if I let it warm up, start driving for a couple minutes and slow down, it will dip momentarily. After driving for a while it will stay hot and stop dipping. Does the radiator 'puke' or purge at a stop? Don't think so, I need to double check. Before I replaced the radiator cap it had a LOT of sand/sludge in the overflow tank. I cleaned that out, made sure the hose wasn't clogged and replaced the cap. I still haven't noticed it purge though. I will check after the next test drive. What condition is the radiator in? Looks like new, guy at the radiator shop said boiling it out would be a waste of time/money. What type of cooling system do you have? Including: # of cores in the radiator? (you have 3, if I remember) clutch fan? Thermal Clutch Straight fan? Viscous clutch, thermostatic? Do you have an overflow tank? Yes How are the hoses, all of them? Seem to be OK. Will the lower radiator hose collapse if you rev the engine? Hope not, I replaced it too, this one has a spring in it. Is the radiator cap in working order? It's also brand new. This might be embarrassing, but everyone has probably done this once: is the t-stat in correctly, and is it working correctly? I think so, the spring part is in the engine and the arrow (pointed part) goes toward the radiator. Do you have a sweet smell if you turn on the heat? No is the water pump "weeping" at the bottom of the shaft? No. Any white or greenish residue around the pump? No. How old is it? Don't know. It was on the car when I bought it about 2 years ago, It looks like it was replaced pretty recently, it's one of the few parts under my hood that's clean :gt: They wore out when new Is there a way to test it? Are the belts to the fan pulley the correct tension? I think so, about 1" play. I replaced the belt too. Overheating is a drag, and worrying about your temp is almost as bad. I agree. I need to drive it and see if it's improved any. I have to work today and have class tonite so I won't get to drive it until tomorrow. Thanks for the help!!! :TU:
Hmmm. Sand and sludge in the overflow...for one thing, it seems you need a cooling sytem flush. To get in the overflow, that sand and sluge had to go through the radiator, and even if it looks new on the outside, it could be clogged. This would definitely cause you cooling troubles. I'm not very familiar with the thermal clutch fans, but it is a possibility that yours isn't working as it should. Being thermostatic, there must be a way to test it- which I don't know of, I only use the viscous ones, myself. Testing the water pump- well, I guess you could get it on a test rig and see how many gallons per hour it pumps- but I wouldn't do it:laugh: If there's play in the bearing with no belts on it, it could be worn out. I've had my engine since '91 and put in 4 water pumps. The belts should have about half an inch play, in general. good luck!
good example; my radiator looks relatively new... but has cold spots (Thanks Mr. Littlejohn :TU: )... meaning I need to have it taken apart and rodded... or just to get a bigger radiator (I will probably go with the latter).
radiator I too am having problems with over heating in my 1964 Riviera. My 1975 455 with 1970 heads that's boiling over. the motor is rebuilt with all new parts including a mild cam edelbrock intake and 750 cfm carb. i've tried a h.d. 4 core radiator that did'nt work and now have a Howe racing aluminum radiator (28"x19") i'm also running two puller electric fans and a 160 degree thermostat. I'm almost ready to change the motor out to something smaller.any help will be greatly appreciated i'm running out of patience. thanks, duane walters
Don't forget timing. I found on my hot running 350 that the timing was retarded and causing my heating issues. Here's a good link, covers most of what's been discussed. Overheating
Just to post for comparison/information sakes. I just put in a new HD 4 core Modine, replacing the original 3 core, and a 180 stat, and I believe I have the 20" 5 blade fan. It was in the mid-high 70's today and I did some cruising today, with the A/C on. On the main road where it goes from 44-55mph, I stayed at about 182, 185 if going uphill. When I got into town and slowed down to stop and go, it was about 190, never getting above 195, again, this was with the A/C on, too. This is with a pretty much stock, original 455.
