390 overheating
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Laughing Gas
Joined: Apr 2009
Posts: 751
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From: orange county, ca.
390 overheating
the 390 is in a '54 f100 panel truck. i put in a 4 core radiator (from the truck shop maybe us radiator?), new 170 t stat, new hoses, new water pump and a 30/70 mix (30 coolant, doesn't freeze around here). all new parts were just to get the truck back on the road. it has an aftermarket flex fan, i made a shroud for it (out of 2 original shrouds). it has a mechanical temp gauge that slowly creeps over 200 in traffic and goes down below 160 with airflow. the 390 is tired and #3 cylinder is at 70psi. i'm going to check the timing tomorrow also i'm running a new 7 lb radiator cap which i'm thinking of going to a 13 lb cap. this is my first ford motor other then a flathead so 200 is high for me, but at 200 it does let some coolant out of the overflow.
Fleet Owner
Joined: Jun 1999
Posts: 24,552
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From: Creedmoor, North Carolina
the 390 is in a '54 f100 panel truck. i put in a 4 core radiator (from the truck shop maybe us radiator?), new 170 t stat, new hoses, new water pump and a 30/70 mix (30 coolant, doesn't freeze around here). all new parts were just to get the truck back on the road. it has an aftermarket flex fan, i made a shroud for it (out of 2 original shrouds). it has a mechanical temp gauge that slowly creeps over 200 in traffic and goes down below 160 with airflow. the 390 is tired and #3 cylinder is at 70psi. i'm going to check the timing tomorrow also i'm running a new 7 lb radiator cap which i'm thinking of going to a 13 lb cap. this is my first ford motor other then a flathead so 200 is high for me, but at 200 it does let some coolant out of the overflow.
Do you run a recovery system? If not (I do not) you need to leave room in the top of the radiator for expansion. Put the new cap on run the truck, let it puke out some and find it's own level. The level in my truck is down a couple inches. As long as I can remove the cap and see the fluid I am happy.
Timing can effect the temps.
Set those things straight and let's go from there.
John
Elder User
Joined: Dec 2007
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From: Up Nort Minnesota
sounds like she's cooling with cruising speed airflow.
that's a good sign, to me it means things are working as far as radiator ability, stat is opening good coolant flow etc.
might want to get more agressive with the fan, maybe think about a real good low rpm air mover & run a thermostatic clutch between the fan & the pulley.
that's a good sign, to me it means things are working as far as radiator ability, stat is opening good coolant flow etc.
might want to get more agressive with the fan, maybe think about a real good low rpm air mover & run a thermostatic clutch between the fan & the pulley.
Tuned
Joined: Jul 2009
Posts: 258
Likes: 18
From: mid-nowhere AZ desert
Mine did the same thing, built 390 in a 69 F100. As they say, extra rows in the radiator does not do as good as more radiator area. If you can get a larger radiator size in it would help. I live where the temps are daily over 100, I fixed my problem with a pair of puller fans on the radiator (work when in traffic at lights) and I also changed to an aluminum manifold, used the HP 390 intake manifold gaskets with the manifold heat crosssover blocked off, phenloic spacer on the carb to keep the carb cooler, higher flow water pump. Not sure which did the trick exactly, as I did them all together, but it worked.
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Joined: Aug 2001
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200 is NOT HOT! You sholdn't be sweating things until the gauge starts pegging 230.
Get rid of the 170 t-stat (where ever you got that, 160, 180, 192 and 195 are standard) and install a 195. The engine will be happier and your mileage will go up which also means your truck will run a constant 195-200 degrees.
Josh
Get rid of the 170 t-stat (where ever you got that, 160, 180, 192 and 195 are standard) and install a 195. The engine will be happier and your mileage will go up which also means your truck will run a constant 195-200 degrees.
Josh
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Laughing Gas
Joined: Apr 2009
Posts: 751
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From: orange county, ca.
sorry, i just re read my post it's a 160 thermostat and the timing is a 7 btdc. also going to a 13lbs cap won't lower my temp i know, but it will raise my boiling point. i have no overflow and it seems to have found it's level. i've read that these run a little warm (i'm used to around 180 max from my other cars). it also has a pertronics kit in the stock distributor and the motor is a '68 390 from a truck (so i've been told). i'll try the 195 this weekend and look into a clutch fan.
Thanks again for all the help
Thanks again for all the help
Senior User
Joined: Nov 2007
Posts: 120
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From: New York City
Yes 200 F is not bad, my truck stays at this temp in traffic. As earlier said, if it creeps up to 230 - then you might have a problem. With all the proper equipment you noted, check your pulley sizes. I had a problem where fan/water pulley was bigger than the crank. Previous owner installed improper set up. I replaced both. Now the fan/water pulley is smaller than the crank...meaning that the fan and water pump spin faster than before and thus eliminating air/coolant circulation issues in traffic.
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Senior User
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If it was me, I would play with the timing a little. Try 16 to 20 degrees BTDC, if it pings, just back it off a little.
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Noted if you were to go with a clutch fan setup you'll need the correct pulleys also. Most water pump non clutch fan size our 7" on these 70's trucks. With the clutch fan our down around 6" with a crank size of 6.3/4" This is what's on mind truck and it is the perfect balance. A radiator will start to clog the tubes in the bottom first were it can't be seen, so if it yours looks clean looking through the filler cap hole it still maybe need cleaned out. Also 50/50 mix is the best mix. Straight Water will even run much cooler the a 50/50 mix but if needed for hot weather and or going up hills your dead at 215+ but a high temp cap will help as long as you don't STOP. I run a 180* stat with the biggest 4 core rad since and clutch fan shroud because of i have AC and for 27ys a 8.5 1200-lb camper. Plus did live in the desert for 12 of these yrs. And did a lot of off road driving then.. Any ways hope this helps in some way..my 2cents
orich
orich
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