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Temp Gauge - How HOT is Hot?? |
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78FordLtd2 
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Joined: 19-April-2021 Location: Canada Status: Offline Points: 115 |
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 Topic: Temp Gauge - How HOT is Hot??Posted: 27-June-2021 at 8:07PM |
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I spent the last few days putting in a new valley pan to fix a vacuum leak around my stock 2bbl intake and decided that today would be a good day to take the LTD out for a test drive. Under normal circumstances, the temp gauge reads about half way or around "M" in the "NORMAL" scale. It might creep up to "A" in stop and go traffic on a warm day (80 ish). Today was HOT (110 F) and my temp gauge was up to the "L". It did not boil over but those hoses were definitely hot. It was a short trip across town (30 mins each way). When I got to my destination, I took a temp reading with my laser temp gun. Upper rad hose was 225*, lower rad hose 195*. I'm running a 185* t-stat, and yes, it is the correct style for a 351M. Checked the coolant level after I got home and after a long cooling down period and it was full. Radiator is a standard 2 row unit and the car does not have A/C.
My LTD ll Sport is not my daily driver and driving it during a heatwave is not exactly enjoyable, especially without A/C and vinyl seats. But how accurate is the factory temp gauge? I should expect it to be spewing coolant all over the place at that high of a temperature, but it didn't. Not even a "hot smell" wafting from the hood. The only indication of it running warmer than normal was a bit of pinging when pulling away from a light. A 3 row rad is in its future but for now, it will have to wait. Oh, and on the 35 min drive back, I had the heater on full blast for insurance...not for comfort. The needle hovered between the "A" and "L". So, what is the safest "hot" temperature on a 43 year old engine? Oof!
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aquartlow
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Joined: 19-December-2011 Location: Summerfield, Fl Status: Offline Points: 2209 |
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Posted: 28-June-2021 at 12:37AM |
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I like my engine to run around 180, I found with higher engine and under-hood temps lead to vapor lock issues as well as pinging, kinda surprised you didn't have the VL issue as well being as hot as your temps were. If looking at getting a new radiator, I use a Champion brand all aluminum 3 row. The radiator fit quite well and all welds look good, been using it since '10 with no issues with the radiator itself. Hope this helps
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www.supermotors.net/22468
Yeah, It's a Hybrid...It burns gas and tires. No matter how good she looks, somebody, somewhere, is tired of her sh*t. Beauty is skin deep, ugliness goes clear to the bone. |
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72 RS 351
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Posted: 28-June-2021 at 1:54AM |
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The 30* drop of the radiator is a decent amount. But the thermostat I would want to swap for sure. The coolant temp in the radiator should be lower than the thermostat rating, at the inlet side. The radiator may need help, have corrosion and old age making it less efficient etc. There's a lot to getting coolant temps down, many things. Use a coolant additive like Water Weter, which increases cooling efficiency. That usually moves the needle slightly, about half a letter on the gauge. Do not use as much anti-freeze as you can(like 50-70%), use only as little as required. Anti-freeze does not transfer heat as well as water. So use just what is needed to match the temps you see in Winter, such as zero degrees as a low. I only need about 30% of anti-freeze here, the rest distilled water. Keep the radiator clear of objects, and be sure the surround pieces are in place(they force air through the radiator). Does the overflow tank work, does the radiator cap keep air out, vent only fluid back in while cooling down? That cap and the thermostat are fragile parts that can go bad early/young. I like a 180* Tstat, and a 160* is good if you tune for it and can get it down that low.
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Don
73 Ranchero "Sport 72 front end", floor shift/console, planning EFI 7000+ rpm 351-4V &4R70W 73 Ranchero GT 351C-4V &4R70W for sale later. 92 Lincoln Mark VII SE GTC, OBDII 347/4R70W |
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72FordGTS
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GTS.org Admin Joined: 06-September-2005 Location: Ontario, Canada Status: Offline Points: 5308 |
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Posted: 28-June-2021 at 8:42AM |
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That seems to be too hot to me. When my 400 was stock and I had a 195 stat, it ran pretty close to 200 at the top rad hose according to the IR gun. My temperature gauge was always on the lower half, and maybe in very hot slow moving traffic would it go up to the halfway point (they aren't exactly accurate though). Now, my engine isn't stock anymore, and I am running a 180 degree stat and the car runs not far off that. I also upgraded to a 3-core high efficiency rad (brass/copper), and a clutch fan. What kind of condition is the rad in? What about your water pump? What are you running for a fan?
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Vince
1972 Ford GTS Sportsroof - Survivor, One Family car GTS.org Admin |
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78FordLtd2
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Posted: 28-June-2021 at 12:45PM |
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I agree, it seems to be too hot to me too. I replaced the t-stat last month with a 185* unit as the old one was slow to open. The rad is in not too bad of condtion. Inside there is some minor corrosion but no leaks. It has a stock 4 blade fan and the shroud is fully intact.
I'm shocked that the rad didnt boil over and all that heat cant be good for the tranny, not to mention the motor. A 3 or 4 row core rad is definitely in its future. I'm equally shocked that I didn't have any vapor lock issues.
Edited by 78FordLtd2 - 28-June-2021 at 12:52PM |
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californiajohnny
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Joined: 05-October-2013 Location: winlock, wa Status: Offline Points: 14467 |
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Posted: 28-June-2021 at 5:41PM |
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those 4 blade fans suck
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JOHN
74 GRAN TORINO S&H CLONE 74 VETTE CUSTOM 90 S10 BLAZER 4X4 LIFTED 77 CELICA CUSTOM 75 V8 MONZA SUPERCHARGED 79 COURIER VERT. SLAMMED 75 VEGA V6 5 SPD 70 CHEV C10 P/U 68 MUSTANG FB CONVERSION |
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Rockatansky
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Posted: 28-June-2021 at 6:49PM |
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a lot of people overlook servicing the trans fluid after running hot and end up wiping out the trans. 225* is getting warm for sure confirmed by the engine knock. a lower rated thermo will not help anything, the heater helping tells you it wants more radiator
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72 GT Ute
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aquartlow
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Posted: 29-June-2021 at 4:46AM |
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www.supermotors.net/22468
Yeah, It's a Hybrid...It burns gas and tires. No matter how good she looks, somebody, somewhere, is tired of her sh*t. Beauty is skin deep, ugliness goes clear to the bone. |
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aquartlow
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Posted: 29-June-2021 at 4:49AM |
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Another thing to check is ignition timing: Initial, mechanical advance and lastly the vacuum advance. I have seen a 15+ difference in operating temperature just by setting the igniting timing to what the engine likes/wants.
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www.supermotors.net/22468
Yeah, It's a Hybrid...It burns gas and tires. No matter how good she looks, somebody, somewhere, is tired of her sh*t. Beauty is skin deep, ugliness goes clear to the bone. |
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78FordLtd2
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Posted: 29-June-2021 at 6:32AM |
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I'll re-check the ignition timing, it might not be happy being set at 14* (engine tag). It might be happier being advanced to 8* or10*. Carb might be a bit too lean as well.
There was quite a bit of vacuum when I pulled off the hose on the vacuum advance to set the timing. I've always thought there should be no vacuum or very little vacuum at idle. All hoses seem to be installed correctly after re-assembly. Well, back to basics and check and re-check everything then. Going to definitely need a bigger rad. We don't see these kinds of temperatures here on the "wet" coast.
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Big Bird
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Posted: 29-June-2021 at 10:32AM |
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Shouldn't be any vacuum advance at idle, ported vacuum.
Running lean will heat it up as well. Sure you got that vacuum leak? Start with moving the advance to ported vacuum.
Edited by Big Bird - 29-June-2021 at 10:45AM |
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"What we do in full frontal view, is more honest than your cleaned-up mind."
Randy 1979 T-Bird 2005 F-150 STX RCSB 4.6, 3.55 LSD How the Heck does a REGULAR CAB SHORTBED weigh over 5200 pounds? |
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californiajohnny
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Posted: 29-June-2021 at 10:56AM |
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WHAT RANDY SAID!!!!^^^ change the hose and retime it
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JOHN
74 GRAN TORINO S&H CLONE 74 VETTE CUSTOM 90 S10 BLAZER 4X4 LIFTED 77 CELICA CUSTOM 75 V8 MONZA SUPERCHARGED 79 COURIER VERT. SLAMMED 75 VEGA V6 5 SPD 70 CHEV C10 P/U 68 MUSTANG FB CONVERSION |
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aquartlow
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Posted: 29-June-2021 at 12:01PM |
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With a low compression(< 9 to 1 CR) iron headed Ford engine, I typically like to start with initial timing at about 14-16 BTDC then add 20 degrees mechanical give or take (all in by 3-3200 rpm), then add another 15-20 degrees of vacuum advance.
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www.supermotors.net/22468
Yeah, It's a Hybrid...It burns gas and tires. No matter how good she looks, somebody, somewhere, is tired of her sh*t. Beauty is skin deep, ugliness goes clear to the bone. |
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78FordLtd2
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Posted: 29-June-2021 at 1:19PM |
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Thanks Randy. Didn't think there would be vac at idle. I'll go back through and check everything again. I have no idea what would be creating vacuum. I believe I have fixed the vacuum leak with the manifold. New gaskets on the spacer plate and new base gasket under carb. Have shot carb cleaner around the manifold and carb and no changes in idle speed. Vac hoses are next to be replaced.
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78FordLtd2
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Posted: 30-June-2021 at 6:30PM |
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Thank you for your help Randy! I ended up going back to basics and retraced my vacuum hoses...it was in ported vacuum, re-set the idle and the timing. Seems to be running cooler (mid way in normal) and better. Timing was off and so was the idle...which explains the extra vacuum. The pinging has vastly improved as well. Looking forward to a nice shake down run this weekend :)
Now if only the price of gas can improve! Lol!
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californiajohnny
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Posted: 30-June-2021 at 10:29PM |
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if the idle is set too high you'll start to uncover that vacuum port and it let vacuum into that port
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JOHN
74 GRAN TORINO S&H CLONE 74 VETTE CUSTOM 90 S10 BLAZER 4X4 LIFTED 77 CELICA CUSTOM 75 V8 MONZA SUPERCHARGED 79 COURIER VERT. SLAMMED 75 VEGA V6 5 SPD 70 CHEV C10 P/U 68 MUSTANG FB CONVERSION |
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78FordLtd2
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Posted: 01-July-2021 at 11:14AM |
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Exactly. I think I was more focused on the timing only instead looking at the big picture (idle and timing), which would throw everything off anyway. Thanks for your help!
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californiajohnny wrote: