ChevroletR Posted March 20, 2008 Share Posted March 20, 2008 I've had some overheating issues (205-215 with 160 thermostat) in the past with my 383 and I'm running a stock water pump and big block 4 core radiator and Stant 160 thermostat. I thought about going to a higher flow water pump to take advantage of the higher capacity radiator, does anybody recommend this or recommend a certain pump (not electric)? Also, I read in a magazine months back that the thermostat is the smallest restriction in the cooling system and that there are higher flow thermostats out there. I know Mr. Gasket makes some, but their quality of stuff never really has impressed me. Does anybody know of a reliable company that produces these and if this sounds like a good idea? Thanks Ryan www.RyansCustoms.com Link to comment Share on other sites More sharing options...
monte70car Posted March 20, 2008 Share Posted March 20, 2008 u could drill a small hole in the thermostat or u could add an small elec. fan to the front of the raditor or even mounted inside the shourd and have a stwich inside to turn it on and off. Link to comment Share on other sites More sharing options...
kc8oye Posted March 20, 2008 Share Posted March 20, 2008 when /where does it overheat? when you are sitting still? is it ok while you are moving? my mild 350 used to overheat all the time when I was sitting still, or rolling at very low speeds. (I got the engine up around 300^F on woodward first time I went) then i had a POS FlexFan. I pulled the shroud off, junked the fan, and installed an electric fan, and all my overheating problems went away. Link to comment Share on other sites More sharing options...
ChevroletR Posted March 20, 2008 Author Share Posted March 20, 2008 Yeah, my Monte gets hot only while sitting or barely moving, like if I have to keep it running in the staging lanes and in nice Baltimore area traffic or at our Ocean City Beach Cruises. As soon as I can get up to speed, she cools off and stays about 185-190. The thermostat is only as good as the cooling system that complements it! I've always wanted a nice electric fan setup, but I still think a water pump, if they do anything better for cooling, would be the next step for me. Link to comment Share on other sites More sharing options...
Sam (Bones) Posted March 20, 2008 Share Posted March 20, 2008 do you have a smaller crank pulley for extra horsepower? Link to comment Share on other sites More sharing options...
ChevroletR Posted March 20, 2008 Author Share Posted March 20, 2008 Nope, factory crank pulley (the Monte's huge 3 ribbed pulley) so no change in water pump RPMs. Link to comment Share on other sites More sharing options...
kc8oye Posted March 20, 2008 Share Posted March 20, 2008 What kind of fan are you running right now? clutch fan? stock fan w/o clutch? flex fan? sounds to me like you just need a better fan, or an electric fan.. I don't think a high flow waterpump is going to do anything for you. in fact, it could make it worse, by increaseing coolant flow, you reduce the time it has to absorb heat from the engine. Link to comment Share on other sites More sharing options...
kc8oye Posted March 20, 2008 Share Posted March 20, 2008 that's odd that you are running 190 with a 160 t-stat tho... i'd maybe take a couple degrees of timing out of it.. and the high flow t-stat might be a good idea. Link to comment Share on other sites More sharing options...
wallaby Posted March 20, 2008 Share Posted March 20, 2008 Mr gasket and Stant make the same unit. Either way, it's an improvement. Where is the temp sender located? There are a couple of places you could put it, some tend to give higher reading than others. I was sweating over a high temp level with mine and found out the gauge was reading a little high. A different gauge in the same place gave me a number I could relax with. Link to comment Share on other sites More sharing options...
kc8oye Posted March 20, 2008 Share Posted March 20, 2008 i keep my sender in the side of the head.. because when you get down to it.. that's what matters the most. Link to comment Share on other sites More sharing options...
Vaughn Posted March 20, 2008 Share Posted March 20, 2008 Everything that Mark said. He helped me with my overheating problem. Mine is a big block but the same symptoms. I first moved my temp sensor which helped my gauge reading. Next I went with a heavy duty clutch fan that made a big difference..but not enough. Mark then suggested a high flow thermostat and that solved my problem. On a hot day I can get at least one hour out of it in heavy traffic without being worried. Vaughn Link to comment Share on other sites More sharing options...
ChevroletR Posted March 20, 2008 Author Share Posted March 20, 2008 What kind of fan are you running right now? in fact, it could make it worse, by increaseing coolant flow, you reduce the time it has to absorb heat from the engine. That's what I thought too, that the coolant would flow too fast. It won't hurt to give it a try I guess. I'm running a rather large flex fan, which I wouldn't think would be a problem. What's the advantage of the clutch? It's not going to go any faster than the flex fan, only opens up the opportunity to go slower, which would pull less air though, right? And the flex fan is designed to flex at higher RPMS. I have the idiot light wired to the factory sender on the drivers head and my mechanical Sunpro (yeah I know...I have their voltmeter too in my car and it always reads 16 volts, yet when I check it with my DVOM, right at the back of the gauge, it reads 14-14.5 like it should) on the passenger head. I know the thermostat is only as good as the cooling system because if the cooling system can't keep it at 160, then the 160 stat really isn't able to do what it was intended for. I'll start cheap and go for the Mr. Gasket thermostat and then go from there. Thanks Link to comment Share on other sites More sharing options...
kc8oye Posted March 20, 2008 Share Posted March 20, 2008 take that flex fan and THROW IT AWAY!! THEY ARE JUNK.. _THEY DO NOT WORK_ put a stock fan with a clutch on it and your problems will go away. or better yet... electric fans.. and the high flow t-stat won't hurt either. Link to comment Share on other sites More sharing options...
502ci Posted March 21, 2008 Share Posted March 21, 2008 I agree, everything I have heard about flex fans was usually bad. They will flatten out at high rpms and not work efficiently, a clutch fan won't and also will use less hp to operate than a flex fan. Bill Link to comment Share on other sites More sharing options...
stangeba Posted March 21, 2008 Share Posted March 21, 2008 Just my two cents on flex fans. I replaced the standard 4 blade steel fan on my 71 350 4BBL (NO A/C) with a 5 blade flex fan from a 71 Z-28 back in 1971. The only time I had a problem with overheating is when I punched a hole in my stock 2 core radiator and the repair shop pinched off the tube to fix it. Never boiled over but ran hot in a traffic jam. I replaced the 2 core with a 3 core and all is well. I do have a stock engine. On the BAD side, FORD had flex fans break off in around 1972. One incident is rumored to have killed a mechanic when it slit his jugular. Bruce Link to comment Share on other sites More sharing options...
ChevroletR Posted March 21, 2008 Author Share Posted March 21, 2008 I know flex fans flex at higher RPMs but I'm having my issue at idle or slow vehicle speeds where there is no road-speed flow through the radiator. What would the difference be in the clutch fan versus the flex fan at these low engine speeds? Why are flex fans so bad? Link to comment Share on other sites More sharing options...
Heckeng Posted March 21, 2008 Share Posted March 21, 2008 I'm going to be the odd ball here, and suggest that you ditch the 160 degree stat. If you thermostat is too low, it will stay open too much of the time, which keeps water flowing constantly through the system, which does not let it have enough time in the radiator actually transferring it's heat. The 160 degree stats were supposedly originally used in cold weather cars to allow the heater to work a little sooner. I'd move up to a 180 stat. Also, I've had decent luck with the metal flex fans, but they can in NO way compare to an electric fan. That would be the best place to start, stick as big of electric fan on that puppy that will fit! Your radiator should not have any issues with cooling your engine in my opinion (as long as it's not crudded up inside), although an aluminum one would work more efficiently. The high flow, or "balanced" thermostats will obviously flow more, and will also be less likely to be forced shut by high flow situations which can happen to normal stats. Here is an example of a high flow/balanced thermostat, you can see the difference between it's design and the standard "flat" type of stat. Milodon 180 degree stat I use this Derale thermostatic switch from Summit which is very affordable and works on ANY electric fan. Thermostat Switch , and have a Griffen aluminum radiator, and a 2800 cfm fan. Check out this thread from a while back too. COOLING THREAD Link to comment Share on other sites More sharing options...
wallaby Posted March 21, 2008 Share Posted March 21, 2008 I guess there just isn't any limit to the number of dollars you can throw at a problem. I suggested earlier that your gauge may simply be pointing at the wrong numbers when eveything is actually fine. Does your engine run badly, or water overflow, or boil over or steam from under the hood or anything? I mean really, would you have reason to be concerned if you covered your gauge so you couldn't see it? I'd get one of those cheap dial thermometers from the auto parts store like this : http://www.napaonline.com/MasterPages/NO...ion=Thermometer and either put the tip directly in the fins of your radiator, or into the water thru the cap opening and see how different the gauge inside and outside read. Link to comment Share on other sites More sharing options...
ChevroletR Posted March 21, 2008 Author Share Posted March 21, 2008 Does your engine run badly, or water overflow, or boil over or steam from under the hood or anything? I mean really, would you have reason to be concerned if you covered your gauge so you couldn't see it? I see what you're saying, but on a nice cool day, the temperature can idle right around 195 and stay there. On a hot day in traffic, or staging lanes in my case, the temperature kept climbing, and climbing and I really didn't want to see where it would stop because I don't really think it would. That's kinda my reasoning for thinking it's not just the gauge, but the fact that even if it is off by 10, 20 or whatever degrees, it shouldn't climb as much as it does and continue, you know? As for answering your questions, I don't recall having any coolant boil from the overflow hose, but then again I'm not outside the car or close enough to be able to hear coolant boil (you can hear it boil in the overflow jug, at least on a friends T/A you could). the engine runs fine except slower E.T.s from when she was running cooler! The radiator is clean, and as for the 180 thermostat suggestion, you make a good point and I'll try that and I think that's the style of high flow thermostat I was looking for so you answered my question! I had the 180 in my 350 now that I think about it again and that was the only cooling system difference between the 350 and 383. Besides, it's a cheap way of trying something new that may work...or at least work better. Thanks Ryan Link to comment Share on other sites More sharing options...
Heckeng Posted March 21, 2008 Share Posted March 21, 2008 Also, a 180 degree stat will keep the amount of thermal cycling down. Heat cycles will stress engines, especially bolting and gaskets, and if you have a 160 stat, if you do some highway driving, and street (stop and go) off and on, your engine will go from 160 to whatever high temp it goes to in traffic, back to 160 once you are moving again, while a 180 will still cycle, but the degree of cycling will be less. It will go from 180, then keep it there longer once you sit in traffic but eventually start to heat up if you don't have enough air movement. If it goes up to 195 degrees, that is only 15 degrees of swing, instead of 35 degrees. Wallaby is right though, you can throw tons of money at a problem if you don't really know the real issue. I think the $15 stat would be the best place to start. The gauge could be faulty too like he said. If the stat doesn't fix it, you might check the gauge. Link to comment Share on other sites More sharing options...
ChevroletR Posted March 21, 2008 Author Share Posted March 21, 2008 My 160 stat doesn't cycle either though...unless my gauge is 30 degrees off or so which is a long ways off because once my engine gets of 160, it won't go back even close to 160 either highway driving or any weather conditions. I think the 180 might do the same thing for me and no cycle either. Again, back to the comment about a faulty gauge, even if the gauge was off, I know for a FACT that my temperature in staging lanes kept climbing and didn't "stop" until I was able to go down the track. I didn't want to see how high the temperature would go if I would have kept sitting there, that would just seem dumb. See my point? If a cooling system can hold its own, I would think there would be a threshold, whether stopped in traffic or not, to how high the temperature would go and would remain there. Since my cooling system has a flaw somewhere, the temperauture keeps creeping up and up, and the idea I have in my head is if I have a bad temp gauge or not, either way I still have my cooling issue that I need to take care of. Another point is how did these cars keep cool before the age of electric fans? The engine is fairly mild, about 9:1 compression, and you would think the big block 4 core radiator would compensate for some modifications from stock. I don't see how the clutch fan helps overheating, I think it would flow less air at idle due to allowed slippage than anything. I can't imagine my 383 Monte with her factory 2 core radiator. I just don't understand...I guess that's why I'm hesistant to put electric fans on because I want to make sure it's maximized with what I have (water pump, which nobody has mentioned yet, thermostat, etc) so in the future the electric fans can do as little work as they need. Something to stick out there I guess Link to comment Share on other sites More sharing options...
Heckeng Posted March 22, 2008 Share Posted March 22, 2008 Nobody has mentioned the water pump because stock water pumps are really pretty reliable. Unless it's 30 years old and the impeller has rusted away, it is likely not an issue. How old is your radiator? Do you still have your fan shroud on the engine? You might have said so already, but I don't remember. The more power an engine makes, the more power also gets wasted in the form of heat, so even though your 383 may be mild, it could be at a level where a mechanical fan just can't do it any more. You are right in your analysis of sitting in the staging lanes. A 180 degree stat will eventually creep up in temp, just like th 160 degree would. Your issue is simply not getting the heat transferred from the water to the air. This could be due to: 1. A lack of coolant flow from the water pump (this is unlikely but possible), 2. A lack of coolant flow due to the thermostat being too restrictive (this is unlikely but possible also), I've run both types of stats on my 454 and they both worked fine, 3. or, you have adequate flow, but the heat isn't being transferred through the radiator (this is very likely if the radiator is old which can mean that there is excessive scale on the tubes) 4. Or, you have good coolant flow, but no heat is being transferred from the radiator because the flow from the mechanical fan is very minimal, or air is being pulled from other areas around the radiator instead of through the radiator. Of course, you could have any combo of those too. If you're sure the radiator is good, and the water pump is relatively new, the thermostat is working and allowing flow through it, then it's your fan setup. Link to comment Share on other sites More sharing options...
ChevroletR Posted March 22, 2008 Author Share Posted March 22, 2008 I've seen these aluminum water pumps that flow a certain percentage more and was wondering if that would be beneficial or not. My radiator is about 5 years old but I have maybe 10,000 miles on the radiator and it has seen at least 4 different flushes where I had to completely drain and fill the antifreeze due to freeze plug issues, and swapping engines, etc. I bought it at a swap meet and it was very clean from what I could see. Yes, I am running the factory 50 gallon drum shroud on her I see what you're saying now. Again, I think I'll go with the thermostat since it would be the cheapest thing to try and see what goes from there. Thanks all again! Ryan www.RyansCustoms.com Link to comment Share on other sites More sharing options...
kc8oye Posted March 22, 2008 Share Posted March 22, 2008 FlexFans can not move enough air.. the Clutch doesn't do much for cooling.. the key is, the FAN.. the factory fan is FAR more effecient then those POS flex fans. the clutch simply lets the fan spin faster then the engine when you are moving the air faster then the fan can.. w/o the clutch the fan actully begins to act like a wall and restrict the air flow. I can assure you before you do anything else, you need a different fan. you would be amazed... if you want to see. take the fan off completely and thread some bolts in there.. go for a ride on the freeway.. I bet you it will run cooler. (just don't sit still for long) Link to comment Share on other sites More sharing options...
ChevroletR Posted March 23, 2008 Author Share Posted March 23, 2008 Hmm, thanks KC. I've never heard of that reason for a clutch fan before. It makes sense though that I think about it. I think I have one laying around and will have to try it. Not for my hot-idle purposes, but something to consider for sure! Thanks, you opened up a whole new revelation for me! Link to comment Share on other sites More sharing options...
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