The roadster is running hotter than ever and I'm afraid we are doing damage when we drive it. We had the radiator rebuilt and it has a new thermostat and hoses. It was running about 200 degrees this Summer and in traffic would climb to 220 then come back down somewhat on the open road. We put in a bottle of "Water Wetter" and (coincidently?) the temperature (even in the now-cooler Fall weather) is now a fairly consistent 230 degrees when fully hot and pretty much stays there--yikes! It's a 348 with three two barrel carbs but is only running the center one-- is it just too lean? We plan on getting the other carbs hooked back up-- might this fix the problem? Is 230 degrees way to hot? Should we not be driving it? Any other ideas?
Carbs have really very little to do with temperature, your issues are elsewhere. Need more info and some pictures. What radiator are you running? What kind of fan? Do you have a shroud on the fan? How big is the radiator? My daily driver runs at about 220 and that is where it was designed to run, but on a hot rod that always seems too high to me. Don
I would go to all the usual places, fan, fan shroud, etc. You said it heats in traffic, that usually means air flow. As a side note, I have used water wetter in an OT car and a motorhome. Both ran hotter.
I believe it's a stock radiator with a fairly minimal shroud--I don't know if these pics are very clear. We are running a 10# cap and no overflow tank--it pumps out about a pint of fluid every time we drive it. There seems to be room for an electric fan between the radiator and grill--I don't like the look but is this a good option?
A lot of unanswered questions,fan,shroud,where is the temperature sensor located,original radiator or aftermarket? HRP
After seeing the photo you might do better by replacing that aluminum fan with a steel bladed fan,those fans are about as bad as tit's on a bowling ball. They don't work properly,check out the all steel fans from summit. I'm a member of keeping a mechanical fan camp and there are always opposing views,both work when properly used,again your aluminum fan is not going to work properly,I've been there,done that. HRP
The 230 degrees reading came from a pyrometer aimed at the upper radiator tank, left (non-cap) side--is this the most accurate place to "read" the temp? The gauge reads 240 at times but we suspect it--or the sensor--aren't accurate.
Is the radiator stock height? Id the gauge "known" to be good? Water pump good? Lots of things to check.
I agree with Hotrodprimer, ditch the flex fan, they are worthless. That shroud is only partially ok, it needs to draw from across the entire finned area, ala a closed faced shroud with only an opening for the fan. Whose radiator is it and how big is it dimensionally? Now, THIS suggestion will certainly cause an uproar, but I am only offering as ONE SOLUTION. Put a SPAL electric fan on it, even if you do it just as a test, and see how that works. I know, I know, I know, it isn't traditional, but if it allows you to actually DRIVE the car, it is sure better than sweating every time you look at the temp gauge. Don
If i under stand you right have three carbs only one dumping fuel are the orher 2 blocked off? If your exhuast is glows or really hot sign of lean uasally dosent take long just acouple of minutes
I ran an alum fan on a street strip car, changed back to a factory steel clutch fan and temp issues went away. Is the car newly built, or did it just start running hot? Flush cooling system Check you have a spring in lower hose Get a new rad cap Make sure you're not running lean, check exhaust manifolds, plugs. None of these are more than a few bucks and takes some variables out.
If you get your shit together you won't need an electric fan. Lots of good suggestions above. Start with: 348's came with a steel clutch fan (or at least my two did) Replace upper and lower radiator hoses with good corrugated ones I believe the radiator cap needs to be about 17# or so Pull out the stats and check them for operability. If in doubt replace Too lean = too hot! That's a fact Jack. However, unless you've F'd around with the center carb that's not the problem. Check for vacuum leak @ idle...spray in the usual places with WD 40
All this. Again, how big's the rad, how's the air flow thru it? PICS!! And if too lean it would run terribly before it was lean enough to contribute the the heat. Also, TIMING's very important as well as checking the accuracy of your gauge. Can you grab a handfull of timing and hear the motor getting much happier while still starting OK when hot? You'd be surprised how many hot cars I've fixed just by timing. Keep us informed
A friend had a 348 in a '34 Coupe, ran 185-190 always. Water pump started leaking, so he replaced it with a 'rebuilt unit', still in the box. (Kragen's back then, 1982) He came to the shop, very worried...temp was now 220, 14 lb. pressure cap, neat aluminum round bottom can for overflow. After checking a few points, ('bleeding' the system for a huge air bubble, thermostat test with thermometer, etc.) I reverted to the obvious: Water pump, as it was the only thing changed. Removing the water pump, all looked normal. I had expected the 'water wheel' to be too far off the ramp, but it looked fine. I felt it for 'play', OMG! The shaft free-wheeled inside it, I could hold the outer pulley flange and spin the wheel on the shaft! Replaced it with a NAPA new pump.
I also don't care for that fan.. If the grille is open on the front??...I always feel all over the face of a radiator to see if it has hot spots or cool spots, especially on an older radiator that might be a little plugged up. another thing I do is feel the air temps and flow coming out the shroud, just to see what velocity is there at random RPMs
Because no two cars are exactly the same, sometimes you have to play around with the thermostat or even leave it out entirely. Currently, I am running NO thermostat in my 27 and that is where it runs the best. I have tried 140-160 thermostats and various size restrictor plates, nothing worked as good as none. But I am with everyone who is saying air flow. And I would still like to hear whose radiator that is in there. Don
We are running a 10# cap and no overflow tank--it pumps out about a pint of fluid every time we drive it.[/QUOTE] Without a recovery tank, this coolant loss is normal due to heat expansion. Gary
A motor with late ignition timing will run hot no matter what you do with the cooling system. Before you start throwing new parts at your cooling system make sure that both of your distributor mechanical and vacuum advance mechanisms are working as intended, your initial lead is set to specs, and that your advance curve is set correctly. I know it's hard to find someone who has one anymore but have your distributor checked out on a machine if you can.
What is wrong with the "flex" fan? Is it that they straighten out and don't move any air? Don't they just straighten out and high speed? Sounds like the main problem is that the car runs hot at idle. If these fans flatten out at idle then that could be the problem So I would look at that. Is that shroud sealed to the edge of the radiator? looks like it could just be a ring around the fan, I can't see. How about how close the fan is to the radiator, It looks like it could go into the shroud some. I understand that running hot at slow speed is most likely an air flow problem but is the radiator clean? I have used water wetter also and if you read the label it says that it is less effective the antifreeze you use, so only use the amount of antifreeze you need. I cool a 292Y block with 9 to 1 heads with a stock non pressureized model a radiator, it only get hot on a very hot day sitting in traffic.
Yes, that is exactly the problem with the flex fans, they don't hold their shape very well and don't move as much air as a steel fan. In fact, on some air conditioned cars they used to put things like 6 bladed fans to move even more air. I ran a flex fan one time and pulled it off when I discovered that the car ran much hotter at all speeds. Don
A steel bladed fan like this moves large volumes of air and does not flex or distort like the cheap aluminum fans,I use this on all my builds. HRP
The Jalopy Journal
