durbon885

Sorry if i am not posting in the correct place but i am having a few problems.

I had a fuel issue that fixed itself with a new fuel filter and hoses and carb rebuilt.

I got the car on the road yesterday after a year layover and had it running for 30 minutes, drove it around the block and had no issue. I go in the house and come out and the car stalled out. I was able to turn it right back on and noticed the overheating light was on and cut it off. The front of the car was HOOOOTTT. I opened the hood and let it cool down for an hour. You could hear the coolant bubbling hot in the hose. What should i do. I bought a new thermostat (195 degree)and will install later sunday. anything other info i can use to problem solve the issue.

What type of coolant should i buy to add? 50/50?

i also bought 5 qts 10w30 oil to do an oil change? it was the weight that was recommended by the auto part store. Is that ok?

Sorry for the newbie type questions and sorry if i posted in the wrong area.

1970cs

Welcome to C.O.
You did not mention how long you were in the house? By rights your thermostat should be open during yout 30 min. drive. Assuming that your car is stock, you can start with the cheap stuff like new thermostat and radiator cap, I would also inspect the inside of the radiator scale and or pluged core.

Coolant 50/50 premix is O.K. I typicaly mix my own from straight coolant and only use distilled water, less minerals

I also use 10w-30 in my 70 350 for years, had no issues.

MDchanic

When was the last time you changed your coolant? Are you confident that it was 50/50 with water?
It should not boil unless it is very hot OR you've got no cooling system pressure (usually a bad cap or a leak).

Before you've sorted the thermostat out, you should check your cooling system pressures. Warm the car up all the way (take it for a drive), then feel the upper radiator hose. It should be very hot and pretty close to hard as a rock. If it's soft, you've got a leak somewhere. The most likely culprit is a bad radiator cap. You can probably get the old one tested at the auto parts store. Caps are cheap.

I would then check the old thermostat alongside the new one before installing it.
Wait until your wife's not watching, and put both in a pot of water on the stove with a candy thermometer.
Watch both of them as the temperature goes up. They should both begin to open at around 190° and be fully open by 200° (well before boiling). If your old one opens later, or if it doesn't open as much as the new one, then it's bad. If they behave essentially the same, then it's not the thermostat.
A 180° thermostat is fine, if you want to run a little cooler, but a 195° is also okay if the rest of your cooling system is good.

It also wouldn't hurt to change the coolant and give the system a flush, if you haven't lately.

Regular old antifreeze (doesn't have to be "Dexcool compatible" or anything like that).
Mix it 50/50 with water (distilled is better, especially if you've got hard water). If you prefer to pay $15.00 a gallon for water, you can buy the "premixed 50/50" stuff.

Did you or didn't you?

Maybe.

In the strictest sense, it is within the recommended range, but I would not use it in the summer, and especially not in an engine that was not recently rebuilt or essentially new.

"Back in the day" you'd use 10W40 summer and 10W30 winter on a normal engine, 20W50 summer if the engine was worn, and 5W30 winter if you lived in Minnesota.



- Eric

joe_padavano

On the topic of 50/50 coolant, why do people buy that product? Straight, undiluted Prestone is about $13 a gallon at the local WalMart. The 50/50 Prestone is about $12 a gallon. Two gallons of 50/50 costs $24. One gallon of undiluted mixed at home with one gallon of water produces the same two gallons of 50/50 for $13. Do the math.

durbon885

well I added some coolant( about a quart, it was flushed and filled about 1000 mi ago), changed the thermostat and radiator cap and after 30 min of running the hot light came on. The hood was hott and i let it air out once again. The upper hose off the radiator was very hot and hard. some coolant shot into the side reservoir and the coolant was again bubbling in the hose.

What should i do & or try next?

Thanks

Dave

MDchanic

Does it overheat while moving, or only when stopped?

How're your fan, fan clutch, and fan shroud?

- Eric

durbon885

I had it in the driveway parked idle for 30 mins. I didn't want to take it out and run into an issue

durbon885

I'm not a mechanic but the fan seems to be running fine

MDchanic

When you first start it, cold, with the hood open, does it blow you hair back (if you've got any left... )?

When you turn the engine off, hot, how many times does it turn after the engine stops?

- Eric

70ConvCutlass

I'm experiencing a similar issue with my '70 cutlass and would appreciate any advice. I've installed a new fan clutch and shroud, a new thermostat and tried to burp the air from the cooling system. I installed a temp gauge, ran the engine for about 15 minutes at idle before it reached 120 degrees. I turned the engine off and the temp climbed to about 125 degrees.

The heater is not working (vacuum system is not connected) so not sure if there could be air trapped there. Not sure what to try next. Was wondering if I cut try by-passing the heater by connecting the two heater hoses.

Still a newbie so hope posting on this thread is the appropriate option. thanks..

oldcutlass

What was the outside ambient temp. Idling for long periods, plus hi air temps = overheating. What does the car do driving around say at 25mph and highway speeds? What temp thermostat are you running? When was the radiator cleaned last and how does it look now?

70ConvCutlass

I had the radiator boiled and pressure checked while the engine was out, and fluif appears to be flowing. The thermo is 180 degree. I drove it tonight since its slightly cooler out (88 Degree), and it overheated in about 10 minutes. It has a stock radiator, i'm wondering if I need to replace it for a 4 core or larger.

oldcutlass

So it overheated while driving? Can you post a picture of your fan and shroud area?

rustyroger

Prime suspect with your symptoms - the radiator.
When you next start it up from cold feel the radiator as the engine warms and the thermostat opens. it should heat up evenly all over the core, if parts stay cold that points to a partially plugged radiator. Flushing a plugged radiator won't do any good.
Try putting the heater onto hot with the fan on full speed to see if that helps slow down the overheating, if it does that also indicates a bad radiator.

Many times I have cured overheating issues by recoring a stock radiator, often after the owners have tried flushing, changing (or worse, removing) the thermostat, adding extra fans, water wetter and other band aid fixes.
Don't forget the stock radiator handled cooling the engine fine when the car was new, unless you have modified the engine a stock radiator will still work fine if it's in good shape.

Roger.

oldcutlass

It also could be a tune issue, headgasket, and what Roger said.

70ConvCutlass

Thnaks guys. The engine has been modified, rebult to include a street pro cam, edelbrock performance manifold and holly avenger carb. The radiator is the stocl 3 core but may not be able to handle the modifications. Any recommendations for a radiator upgrade? Started searching on line, looking at Griffin, Alumitech, Be Cool and Desert Coolers...

hamm36

I would recommend a upgrade on any for a new replacement. I got a new four row radiator from these folk at a good price.
Xcel Cooling Products

(214) 237-3838
10930 Alder Cir, Dallas, TX 75238

rustyroger

This is normal.
The water pump stops circulating coolant as soon as you switch off, the hot coolant around the cylinder heads and top of the bores carries on absorbing heat and so you see a rise in engine temperature until the heat radiates from it.
After 10 minutes or so the temperature should drop a bit when you restart and send the hot coolant away to the radiator and colder coolant moves around the engine.

Years ago I had a slant 6 powered Dodge truck that had hot starting issues, leaving the hood open if I stopped for a short while for gas or whatever it helped ease the carb getting heat soaked.
This applies to any engine, some have more of a hot start problem than others, fuel injected engines have much less of a problem as fuel is constantly circulated through the injection rail helping prevent fuel vaporising.

Roger.

70ConvCutlass

I purchased an Alumitech radiator and hope to get time to install it this weekend. I'm thinking i may also bypass the heater (which doesn't work) to make sure I don't have air trapped in the system. Also, I released I had never filled fluid into the reserve tank and there are never been any signs of fluid. When the car over heats fluid usually puddles on the intake manifold around teh base of the t-stat. I've have already retighted and resealed those connections. Since the reserve tank was "dry", I'm wondering if the system fluid level had been low from the get go.. Also... Since the engine rebuild did include a modified cam, intake manifold and carb should I consider installing a performance watrer pump? I'm not noticing any signs of wear but is is a stock remanufactured wp..

marzgtp1

Let me know what happends im having the same issue. Also when the engine gets hot the car doesnt want to restart it just clicks as if the battery was dead any ideas what to do.

70ConvCutlass

I pulled the original radiator. Need to replace the lower brackets with 4-core size brackets to accommodate the larger radiator. Was hoping the brackets would bolt in but looks like they are welded to the bottom frame; and I don't have a welder. not sure what to do now...

70ConvCutlass

Well, I've installed the Alumitech radiator this weekend. Filled the radiator with water only to flush the coolant. The temp gauge held at 210 degrees. Then, after cool down I replaced the radiator cap and restarted. After a couple minutes the temp seemed to be going higher then 210 sp I shut it off. So, I'm guessing the issue may not be the radiator after all....

70ConvCutlass

70ConvCutlass

Also wondering if the fan could be installed backwards? Not sure if that would cause severe overheating. Does anyone have a photo showing how the fan is installed or any descriptions I can use to double check my install??

oldcutlass

Do you still have a 195 degree thermostat in it or a 180? On a hot day, at idle, your temps probably will climb to around 210 - 220. Also if your fan clutch is not working properly, your timing is off, carb not set right, or idle is to low, you will have a hard time cooling it at idle.

My main question is what are your temps at cruise. That will tell you if your radiator is substantial enough with air flow. Once you establish that then you have to get more airflow at idle.

70ConvCutlass

Octania

Evidently you worked arond that problem by now

Welding is ONE way to fasten parts together
You may elect to use another
Bolting, rivets, JB Weld, zip ties...

stop by 'thereifixedit.com' for more ideas.

So, let's see them photos of the fan area. Hope you are not the same guy I just looked at photos from in another thread...

arodenhiser

I had a solid spacer/fixed fan on my 350. After having some work done by someone else it started over heating. They put the fan on backwards. It could be done. My fan blade did actually say "FRONT" on it. I figured it out when I had the hood up while the engine was running. It was blowing hot air out of the grill and not blowing the air over the engine. While driving the fan was blowing air against the air flow from the forward motion of the car. This caused no, or little, air going throught the radiator and caused my overheating.

Adam

70ConvCutlass

Thanks guys. I ended up bolting the new lower brackets onto the frame. The Alumitech radiator seemed to fit right in. Since my heater does not work I'm going to disconnect the hoses and by-pass the system. Not sure if it has air trapped in it but seems like the next logical step. I confirmed the fan is installed correctly.

Also, someone local suggested I disconnect the coil, ground it to the engine and try to crank it over. If the radiator fluid goes up it could be a sign of an exhaust/header leak.

MDchanic

I don't want to rain on your parade with this one, but, as Octania already pointed out in another post, if you flip a fan over backward, but still turn it in the same direction, it will blow the same way.

Look at it this way (this is the top view of one blade of your radiator fan):

If you turn your computer screen upside down (the same as turning the fan in the picture backward), the line still goes from the top left to the bottom right.

There are "Front" and "Back" differences to these fans, but they don't affect wind direction.

- Eric

bdub217

you would have to rotate the blades on their axis that connects to the wheel part of the fan 180 degrees to achieve a directional change in air flow, or spin it the opposite direction like you said. I'm guessing something's plugged......

- Brandon -

ah64pilot

Sorry Eric but the pilot in me wouldn't let this one go. You have to take into account blade design and unfortunately there is no simple angular blade on the market. Here are the two blade designs found on common water pump mounted fans. You can see clearly that rotation and blade direction has EVERYTHING to do with which way the air flows.

Normal:


Fan mounted on wrong side:

MDchanic

Ah, but what I said was this:
I can see from you much better drawing of the two airfoil shapes that the fan will pull much LESS air when installed backward, but, in spite of major cavitation on the back side of the blades, the overall direction it is trying to blow the air will still be backward, just with much less flow.
I have not actually done this experiment, but I would imagine that the result would be that it would not blow your hair back like it should, but that it will not be blowing wind out through the grille either.

I'm not saying that the fan will work fine backward. Obviously, Aaron's fan didn't work well when turned around. I'm just making the point that the intuitive idea that it will blow just as hard the wrong way if you reverse it is not correct, and that if it's backward, you may still feel a slight breeze, so you shouldn't take that breeze as proof that the fan is installed the right way.

Sorry that I wasn't clear, and thank you for drawing those fan blades properly, so that I can understand why they don't work well backward .

- Eric

ah64pilot

Actually the flex fan has a better chance of pulling air as it spins when mounted backward because it is close to your simple drawing of a straight line. However the clutch fan design will be more neutral because it is simply moving the air out of it's own way rather than pulling it one way or the other.

And nobody noticed I drew the direction of rotation backwards...sheesh! You guys are losing your edge...that has bugged me for days but I didn't wanna take the time to change it lol!

arodenhiser

I too can say sorry for being unclear. I did not intend to make anyone think that, when my fan was on backwards, my grill acted like a hair dryer. With my fixed, non-clutch fan, there was always a draw through the grill into the rad and so on. The reason I figured out the problem was I was standing in front of the car to release the hood (the release is in the front bumper on a '68) and there was HOT air coming out of the grill while the engine was running. That was "eureka" moment.
With the fan on wrong there was not enough draw/flow created to pull the air through the rad. It may not have been blowing the air the wrong way, but it was not pulling correctly. The 10 minutes it took to loosen the belts and swap the fan around change my driving temperatures by about 30-35F.
I now have a 6 blade clutch fan setup and never see above 200F in any conditions.
No hard feelings Earl, I mean Eric. You are a wealth of info any thanks for calling me on my lack of details.

Aaron, I mean Adam

rustyroger

What were they smoking when they suggested that?.

Roger.

1970cs

[quote

Also, someone local suggested I disconnect the coil, ground it to the engine and try to crank it over. If the radiator fluid goes up it could be a sign of an exhaust/header leak.[/QUOTE]
I think that this was misconstrued! Is it possible that he was saying remove coil wire(no start) fill radiator up close the neck and turn over engine may show blown head gasket or cracked head pushing compression back into coolant passage also this may not be conclusive in some situations require heat (engine running @ temp) do to expansion. It's also possible to see air bubbles in the coolant.

I have seen this on diesel tractor engines before! Yes it is easier to spot due to 400+ compression

Pat

70ConvCutlass

I kinda got distracted helping my son wrap-up paperwork for his Eagle Scout board of review. Back to my overheating problems, can you guys take a look at the picture and tell me if the fan looks like it is mounted correctly?

https://classicoldsmobile.com/forums...-img-2475.html

MDchanic

Nope, your fan is attached the right way around.

- Eric

GreekDog

This EXACT same thing happened to me.

My clutch fan was bad as well as my water pump. I also "recored" the radiator.

My radiator ended up being 2/3 clogged with garbage.

You can test the clutch fan by grabing the fan(when the car is off) and trying to move it. My buddy explained to me that their should be some tension and at least a little difficulty in turning the fan. My fan was able to move with the slightest tap of the finger.

You should also check your water pump.

First thing I would do if I was you would be to get that radiator cleaned out. Chances are there is some serious buildup.