302 ford will not warm up in cold weather??

Bottom line here is he says the guage won,t even come up to first line. So thermos backwards would make it overheat eventually as would the pump running in wrong direction. What size rad are you using. I had a 66 mustang once with a 6 and took the fan off in the winter. But then again i live in Canada. Run a 190 stat.

 

Are you sure you have the right water pump..a serpentine pump is reverse. HRP

 

No heat -
Check heater hoses for warm by touch.
If one is warm and the other cold, there is no flow thru the core.

If both are hot, check heater door

If both are cold check operation of thermostat and coolant flow thru block.


Radiator is not involved other than being full and not frozen.

I don't know that its possible to radiate enough heat off of the block to avoid reaching operating temp with a properly functioning thermostat.

 

Here is my thinking on it. You want a radiator to be efficient, but not TOO efficient. The water returning back to the engine, after going through the radiator, should have some heat left, otherwise it is like putting a hose into the intake with cold water coming out of it. The block, regardless of the thermostat, will not be able to bring that water up to full temperature.

If it were not the case, engines would immediately come up to the rating of the thermostat, rather than taking a little while to do it. The coolant has to be maintained at very close to the thermostat's rated temperature to operate properly.

Don

 

Thermostat is the key here . He says the temp guage won't go past the first mark. So the stat must be open all the time and or the rad is to big to complicate things.

 

I have an 87 5.0L Ford mustang. The supply hose that goes into the heater core should have a flow restrictor inside of the hose. I've been told its there to protect the heater core from too much pressure or to slow the flow down to allow the heater core to remove more heat from the coolant. Could this be the problem? Also, if you google 302 SBF coolant flow you should be able to find a diagram of the coolant flow.

 

Fellas....For the 3'rd time....he says the guage does not go past the first mark. So of course there is no heat.

 

I have a bronco that I am fighting the same issue,the temp gauge does not go up as far now that its cold but both heater hoses are hot so I think my problem is with the heater it self. I chased the same problem in my 65 custom 500 and it turned out to be a bad heater core and a new heater core does not mean it will be good as I bought the first one for the 65 and it put out less heat then the original. It came from the factory plugged up and the second core is now putting out great heat.

 

It really has to be a flow problem: i.e. too much flow.

We can all agree that a stuck (closed) thermostat WILL cause overheating in all cases.
And that a stuck open thermostat will cause an engine to warm up very slowly, but that it should get to reasonable temp, given stock cooling.

So, your engine never gets to temp, And you have some mismatched pieces. You should look there first. 4 bad thermostats is a bit much.

I agree with blocking the upper hose, for diagnostic purposes. It should overheat, and fair quickly, too.

I disagree with looking anywhere but the engine's water flow, as the Problem is no warm up, the Symptom is no heat. When you go to the Doctor with a symptom of 'cannot grasp an object', the Problem could be that you cut off your fingers. Therefore the need to address the Problem, first.

Cosmo

 

Racing engines were often run rich to run cooler so smaller jets would make it run hotter.

I was thinking about what could take heat out of the engine. Headers are used to get the exhaust out of the engine faster and that gets the heat out of the motor too. Maybe some restriction on the exhaust would help.

Ignition timing can cause coolant temperatures to rise.

Cam overlap allows intake air to flow through the combustion chamber and cool it. Restricting the exhaust would limit that flow.

Aluminum intake manifolds transfer heat better than cast iron so the cold from the intake air and general air flow over the motor could transfer to the coolant in the manifold. Many vehicles Use a thermostatically controlled damper that pulls warm air from around the exhaust manifolds for combustion.

Just air flow over the motor can cool it. There are many air cooled gasoline and diesel engines. Blocking the air flow by covering the radiator or grill and removing the fan or using an electric fan that only comes on when the engine reaches operating temperature could limit that heat loss.

Even if the engine temperature only reaches 120 degrees, a good heater should be able to heat the vehicle. I don't know how large the heater core is in the Vintage Air units. They might be designed for warmer weather figuring that people aren't taking these vehicles out on cold days. I had an International Scout with a 345 that didn't get very warm and the heater didn't put out much heat. The body rusted off and I put a Vega wagon body on it. I was very surprised at how much more heat I got from the Vega heater.

 

I know a bit about this subject. I have a 53 Ford club coupe with a BBF in it. It uses the stock 53 Radiator set up for the big block. In the winter it never gets warm period. 180 degree thermostat. Just when you start to get a bit of heat in the car the thermostat will cycle. You can watch the temp gauge, Mechanical, move up to 180, Thermostat cycles and gauge drops to Zero!!!. This problem is what some have said - A tooo efficient cooling system.

 

This thread made me think back . Anyone remember Gus's garage books? He may have been fiction? But he solved problems and I remember when he fixed a car that wouldn't heat by replacing the thermostat with a large diameter washer with a small hole. Just water flow resistance . Good luck and please tell us when you fix it.

 

Again please post when you find the fix. Maybe a visit to a good radiator shop?

 

I really can't see "too efficient of a cooling system" ever being an actual problem. I can see the circumstances presenting in such a way those symptoms would lead to that conclusion - but it would be false.

A 190 thermostat should be closed at 180 and open at 200. These things, thermostats, don't open and close like flood gates. The don't go from off to on and stay on allowing an engine to flood with cold water, or as if running a garden hose. If those things are indeed actually happening there's a problem for certain, however its not that the radiator is too efficient.

 

I'm going to chime in here, only because I have some experience here. Your stuff is fine. I'm assuming you changed a bunch of stuff on this engine. '91 5.0 would have been fuel injected, now you have aluminum heads and intake, and a carb. This changes the dynamics of the engine, and as a whole, it is going to stay cooler than it would have stock.

Now then, you can do a couple things: 1)keep it simple and block off the radiator in the winter, which is not a big deal. Case and point - I had a 65 mustang, 289, everything was fine. Summertime the damn thing would overheat in traffic and 95+ weather because it didn't have a fan shroud. Winter you couldn't keep your toes warm without blocking the radiator. There's a reason you see big rigs with their radiators covered. It's cheap and effective, and all it requires is a couple minutes to change from winter to summer operation.

2) You can restrict the water flow with a hotter thermostat, 195 or better, which doesn't really seem to be working for you, or you can restrict the water flow overall, which would mean a smaller lower hose. Keep in mind that this might create problems in the summer.

There may be other solutions, but honestly, you don't actually have a problem. What you have is a hot rodded engine, which means stock solutions probably aren't going to work. You've made the thing more efficient at producing power, so it stands to reason that you have made it more efficient at other things too, like cooling itself.

Mike

Interested in seeing what route you take....

 

Also of note here: bear in mind that you are adding in an additional radiator (your heater core) in the winter. In the summer this is roughly a negligible system until you begin to overheat (it's the reason you can turn on your heat and cool the engine down). This doesn't require going through the thermostat. You have one port on the top of the intake manifold and one port directly on the water pump. So your thermostat doesn't even play in. This is a BIG DEAL in the winter. It's also why you need to block the radiator rather than deal with the thermostat. The thermostat isn't even factoring in.

(Apologies, this all just occurred to me that after the last post.)

Mike

 

If the thermostat is closed, the radiator and cardboard and unicorns are not involved into the liquid cooling system. If its not heating there's either some loop that is including the radiator or the thermostat isn't closed.

With the Tstat controlling the warm up time to operating temperature, the only cooling available is radiant discharge of heat and the air moving thru the heater core. If radiant discharge is that great blocking the fan should help. Easy enough to unbolt the fan and test that hypothesis.

A bit off topic, but I drilled a small hole in Mommas tstat on her GTP Grand Prix. The computer threw a code saying that its taking too long to warm up. That tiny tiny hole (1/16) was providing enough flow that the computer noticed longer warm up times.

 

A little more spitballing here. I also have an SBF that runs cool, but not as cool as you describe.
How is the engine's overall performance?
Maybe you have too much fan? Or the fan clutch isn't working right?
It is possible you lowered your compression ratio with the new heads? How did the chambers compare with the originals? Is it possible you have cam timing issues? Did you degree the new cam?
I agree with the posts above regarding rich jetting, and I'd also look into ignition timing. Retarded timing results in hot idles, so advanced timing means cooler temps at low RPMS.

Focus on the engine temperature and then look into the cabin heater issues. I have a buddy that swears that since he installed headers he can't get enough heat in the winter.

 

That "loop" is the heater core. Basically a smaller radiator, subject to cold air (inside the vehicle) that is independent of the thermostat.

Therefore you have a radiator that is not controlled by the thermostat. Of course, you still have a larger radiator sitting at the front of the vehicle which is subject to very cold air. Your block and "mini-radiator" are getting all nice and toasty, then WHAM! the thermostat opens and pours all that nice, hot coolant into the very cold radiator up front, allowing icy water into the block and your "mini-radiator." This results in having to warm all that water up yet again, with a still-chilly passenger compartment.

It never keeps up. And the colder the weather, the worse the problem. Your engine will reach a low range operating temperature, and your passenger compartment will stay chilly.

Let's reverse the problem.

You have an engine that is getting too hot. You know the thermostat opens, hell, you've checked it a dozen times and replaced it with 6. Same problem with each one. Now, odds are good you didn't get 6 bad stats in a row, so you leave one in and start looking at other problems.

Well, you notice that when you turn the heat on in the cabin on a hot summer day, the temperature on the gauge drops, but problem is, it gets damn hot in that cabin! So you determine that you need more airflow through your radiator.

You go through the steps and replace the fan with a high-volume unit, and you install a shroud. Well that helped quite a bit. Now you don't have to turn the heat on in the cabin, you stay cool, and your temp gauge doesn't peg on the high side.

Back to our original story. You can't effectively reduce airflow through a radiator to warm it up without decreasing the surface area. Removing a shroud will help somewhat, but who wants to install that every summer. Installing an electric fan, or a fan with a clutch will help somewhat, but that's limited. But hey! We can do this real simple! Let's just block off air from reaching a part of the radiator! POOF, problem solved.

 

But here's my question: (sorry about going off on this guys...) Assume you have the engine running right, just the way you want it. 10:1 compression, headers, carb jetted just right, timing is spot on, and it pulls hard and runs great. You can still have this problem. There doesn't have to be something wrong with your engine to make it run too cool. Same reason there doesn't have to be something wrong for it to run too hot.

Airflow plays a big role. So what if the headers make it run cooler? You installed them because you wanted the power. Don't go back to manifolds because the temp is right. Adjust the temp to work with your new engine setup.

 

If you have a bad head gasket the engine will never produce enough heat.

After the engine cycles have you check the water in the radiator after it cools off? HRP

 

Just look in the radiator and see if there is circulation If there is the thermostat is not doing its job.

 

Sorry to disagree, but engineers have been designing cars for 100 years to run within an "ideal" temperature range for a variety of reasons. Efficient combustion, evaporation of moisture, etc.

If an engine doesn't run in the ideal range, then something is wrong. You don't just put on your big-boy pants and live with it. Just because a problem is elusive doesn't mean you throw in the towel.
We don't do these things because they are easy, we do them because they are hard. JFK

 

Two pages and not once has it been mentioned what the actual coolant temp is. Gauges are notoriously inaccurate and should not be relied on for diagnostic purposes. Even if the coolant is only at 130 it is 90 degrees warmer than ambient at 40, if the heater core is only 50% efficient that's still a 50 degree difference. The coolant should flow to the heater circuit regardless of whether the thermostats is opened or closed. So either the core is not getting proper flow, or it is not getting sufficient air flow to overcome the cabin ambient. So let's start again with the question what is the actual temp of the coolant when the engine is at operating temp as it sits right now? By the way rule of thumb for modern cars is that the heater core will provide between 25 to 35 percent of total cooling. So if your heater core is oversized in cold weather it may it self be part of the problem. My car runs at 180, air coming out of the heater outlet with fan on medium speed is 95.

 

I agree. Many years ago I had a friend who complained that his car wasn't throwing enough heat. I suggested a piece of cardboard in front of the radiator. He thereafter blamed me for blown headgaskets that he already had.

 

I'll be honest, I didn't read this whole post:
I only made it this far - then WHAM! the thermostat opens and pours all that nice,

Thermostats don't open like that,

 

I always thought a bad head gasket made the engine overheat. Mine did when my head gasket went.

 

I had a sbc once that ran perfect, temp wise in the summer. I had Vintage Air heat and a/c. In the winter the engine would not produce enough heat to warm the interior of the car. I blocked off some of the radiator with cardboard and the problem was solved. Operating temp came up and shrinkage went down.

 

Depends on the "badness" of the gasket. A coolant leak into the combustion chambers will cool them down up to the point where enough coolant leaves the system for air pockets to form, then whammo, the temperature skyrockets.

 

Bingo! That's what happened to me.