Hello, car runs and drives pretty good. Can basically drive all day in traffic at slower speeds, but if I run a few miles on the highway it gets hot. I have flushed the radiator and tried two different thermostats. I now have a 160 in. It doesn’t leak fluid and the heater works. I can hear like thumping or bubbling in the dash it seems on the passenger side and the fluid boils after driving...really want to drive car to shows and stuff...could the timing have anything to do with it? Thanks
1967 318 Barracuda running hot...
- Thread starter Badfish1
- Start date
-
Alaskan_TA
Well-Known Member
Running hot or actually boiling over?
Factory gauge alone or with an actual temp gauge installed?
Factory gauge alone or with an actual temp gauge installed?
Yes its possible. Insufficient timing for the rpm or mixture can put more heat into the cylinder walls and exhaust.
There are other possibilities too. But that is one.
How is the oil pressure at speed? If it drops after driving on the highway for a while, then it too is getting excessively hot and/or bearings are worn or similar.
Is it losing coolant?
On a vehicle without an overflow tank, the coolant level will be about an inch below the filler neck when checked cold. (Always check cold - never hot.)
Thank you for the reply. No the oil pressure never drops...I do not have an overflow canister. Just a hose running from neck of radiator
I think timing is a possibility, as well maybe insufficient pressure in the system (bad cap or pinhole leak).
Its worth checking the timing at rpms above idle. Being a 318 in '67, not sure what it will be. But you can check boththe '67 273 specs and a '68 or later 318 spec and see if its in the ballpark.
Its worth checking the timing at rpms above idle. Being a 318 in '67, not sure what it will be. But you can check boththe '67 273 specs and a '68 or later 318 spec and see if its in the ballpark.
My 67 273 would boil over especially after shut down. until I started refilling the coolant with the car on a slant (nose up). My driveway is sloped and I put it on ramps. that way the rad inlet is higher than the rest of the system.
the gergalling you hear under the dash could be trapped air in the heater core. Mine did it for a few weeks from the last refil but last weekend I changed out the the T stat gasket and din the noes up refil.
Also if the fluid is traveling too fast through the engine / radiator it can not pickup or expel as much heat. I run a 185 thermostat and a 16 lb cap, factory pulleys. There is no fan shroud and the stock fan sits ~3 inches from the radiator. It will idle all day that way and when I run it on the hwy the temp goes from mid gauge to a few ticks over the low side of normal.
IMHO the issue you are having has to do with engine RPM higher = not cooling as well
I would look at the spark curve as mentioned before and also see if you can see the impeller through the lower radiator hose to be sure it is intact. measure your crank pulley and your water pump pulley and ask here if they are OE.
Drain the fluid out and refill either with the front end up or you can fill with a funnel through the radiator hose till the upper fitting on the manifold shows fluid then reattach the hose and finish filling in the radiator. also make sure the heater hoses are on correctly (in 67 273 the drivers side heater hose goes to the water pump by the bypass hose.)
If it was me I would put the stock thermostat back in what ever temp rating it was OE
good luck
the gergalling you hear under the dash could be trapped air in the heater core. Mine did it for a few weeks from the last refil but last weekend I changed out the the T stat gasket and din the noes up refil.
Also if the fluid is traveling too fast through the engine / radiator it can not pickup or expel as much heat. I run a 185 thermostat and a 16 lb cap, factory pulleys. There is no fan shroud and the stock fan sits ~3 inches from the radiator. It will idle all day that way and when I run it on the hwy the temp goes from mid gauge to a few ticks over the low side of normal.
IMHO the issue you are having has to do with engine RPM higher = not cooling as well
I would look at the spark curve as mentioned before and also see if you can see the impeller through the lower radiator hose to be sure it is intact. measure your crank pulley and your water pump pulley and ask here if they are OE.
Drain the fluid out and refill either with the front end up or you can fill with a funnel through the radiator hose till the upper fitting on the manifold shows fluid then reattach the hose and finish filling in the radiator. also make sure the heater hoses are on correctly (in 67 273 the drivers side heater hose goes to the water pump by the bypass hose.)
If it was me I would put the stock thermostat back in what ever temp rating it was OE
good luck
Per heater section (1-5) of 67 Shop manual. This is for Dart Coronet and Charger maybe Barracuda is different?
340doc
Well-Known Member
Good idea to make sure the timing is good and the vacuum advance is working. Check the cap for sure, had an issue like this and found the cap to be bad. If you've eliminated everything else you might be looking at getting the radiator cleaned.
69FBCuda
Stand back 10' for your viewing pleasure & Safety
The Thumping is the coolant boiling, are you using antifreeze not just plain water? Like Dana67Dart said go back to the stock thermostat temp 195+/- you could be getting hot spots from unrestricted flow creating hot pockets in the circulation loop. Plus open the heater so that whats in there will circulate in the event you are getting air pockets.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
- Joined
- Jan 19, 2014
- Messages
- 24,870
- Reaction score
- 12,217
Overheating at speed usually means the rad can't shed heat fast enough.
Either the air-stream is not getting to it, or thru it, or out from under the hood.Or
the heat transfer from the fluid to the metal to the fins sucks.Or
you have a crappy heat-transfer medium.Or
you are stuffing way more heat into the rad than it was designed for.
So;
First question is; is the rad sized correctly for the engine?Are the rad fins still attached to the tubes?
Second is; what coolant are you using and at what percent water?
Third; does the lower rad hose have the anti-collapse hose in it?
Does the car have A/C?
Is it an automatic? What stall? Auxilliary cooler in front of the rad? Any trans issues?
Headers or logs?With free-flowing exhaust?
What rpm are you cruising at? With how much total timing at that rpm?
And then;how much power is that bad-boy 318 putting out; or rather what size cam are you running?Was it installed correctly?Iron heads? Do you know your cylinder pressure?
You still got that front license plate mount on there?
Are there any chassis issues like dragging brakes and severely under-inflated tires or dry U-joints ,or does it needs an alignment bad?
And like somebody said; is the waterpump turning?And in the right direction?
________________________
I have never in 50 years needed to burp an SBM.
I have a dial-back timing device on my dashboard. It has a range of 15*. My aluminum headed,10.9Scr,367 cuber,cares not a whit about cruise timing as it may pertain to the temperature gauge. So while retarded timing can send heat into the exhaust, that's for sure, my temp gauge never sees it.
_________________________
The heater has nothing to do with an engine overheating issue. Running it in reverse-flow only traps air and makes it noisy,usually just for a while.
Either the air-stream is not getting to it, or thru it, or out from under the hood.Or
the heat transfer from the fluid to the metal to the fins sucks.Or
you have a crappy heat-transfer medium.Or
you are stuffing way more heat into the rad than it was designed for.
So;
First question is; is the rad sized correctly for the engine?Are the rad fins still attached to the tubes?
Second is; what coolant are you using and at what percent water?
Third; does the lower rad hose have the anti-collapse hose in it?
Does the car have A/C?
Is it an automatic? What stall? Auxilliary cooler in front of the rad? Any trans issues?
Headers or logs?With free-flowing exhaust?
What rpm are you cruising at? With how much total timing at that rpm?
And then;how much power is that bad-boy 318 putting out; or rather what size cam are you running?Was it installed correctly?Iron heads? Do you know your cylinder pressure?
You still got that front license plate mount on there?
Are there any chassis issues like dragging brakes and severely under-inflated tires or dry U-joints ,or does it needs an alignment bad?
And like somebody said; is the waterpump turning?And in the right direction?
________________________
I have never in 50 years needed to burp an SBM.
I have a dial-back timing device on my dashboard. It has a range of 15*. My aluminum headed,10.9Scr,367 cuber,cares not a whit about cruise timing as it may pertain to the temperature gauge. So while retarded timing can send heat into the exhaust, that's for sure, my temp gauge never sees it.
_________________________
The heater has nothing to do with an engine overheating issue. Running it in reverse-flow only traps air and makes it noisy,usually just for a while.
Last edited:
69FBCuda
Stand back 10' for your viewing pleasure & Safety
Are you running a solid or clutch fan?
With the thermostat HOT(open) do you see circulation in the radiator(do no open hot)
Have you checked the exhaust for obstruction or blockage, is the stock pass side manifold riser opening and closing smoothly?
Post some under the hood pictures for reference
With the thermostat HOT(open) do you see circulation in the radiator(do no open hot)
Have you checked the exhaust for obstruction or blockage, is the stock pass side manifold riser opening and closing smoothly?
Post some under the hood pictures for reference
Last edited:
I had a 318 fury years ago that always ran over half on the temp gauge. It ran like a champ, but running over half bothered me. So I checked the T stat. 195. So I put in a 160. She made 20 miles and started getting hotter and hotter so time for a 180 T stat, she made about 50 miles b4 getting hot. Went back to a 195, no more problems other than the gauge reading over half. I fixed that by pulling the cluster and tweeking the needle of the temp gauge. Kim
famous bob
mopar misfit
bubbling noise = air in the system.
Hi way heat is an air circulation problem. If it cools in town at low speeds, u don't have rad blockage problem !
Did these cars have hood seals for the upper radiator support? If that rubber seal is not there it can cause turbulence and a vacuum that causes the air to not move through the radiator at speed. Common problem with B-Bodies.
-
