Radiator/Temperature Question....

[sgplancer]

Bought a 69 about a month ago, and love this thing.  Needs work, but very complete, and very little rust.  Well, on to my question...

 

So as you see, I live just 2 miles north of the core of the earth, here in Houston, and it is already blazing hot outside.  The dime has what looks to be a standard radiator, and an L20B motor.  One of the previous owners thought it would be good to remove the clutch fan, and install an electric fan between the grill and radiator.  The temp gauge in the car has a small dot, just past C, and about two thirds of the way to H.  What is this mark for?  I am assuming normal operating temperature, but I could be wrong.  I haven't driven it too much in the heat, but cruising down the freeway, the temp gauge goes above the small dot mark.  My plan is replace the radiator with a Koyorad Aluminum radiator.  My next question....  Should I replace the electric fan (which is hard wired to stay on) to a clutch fan, or get a new electric one.  Also, should it be mounted between the motor and radiator, or is the current location acceptable.  I feel that since it blocks the natural flow of air across the cooling fins, it would be best served to put it between the radiator and motor.

 

Be gentle....  First post on the forum!

[heywier427]

No questions answered until pics are supplied.

 

Welcome.  We like pictures :)

[sgplancer]

No questions answered until pics are supplied.

 

Welcome.  We like pictures :)

Thanks for the welcome!

 

As for the pictures, what do you want to see?  Here is what I am thinking...

 

Picture of the temp gauge

Picture of the current setup

 

Let me know if this is what you mean.  Also, and since I am new, is the only way to post a picture by a url?  We can't attach a jpeg, bmp?  Thanks!

[racerx]

better to install mechanical gauges: voltage, temp., and oil pressure.  No second guessing.

[Draker]

Mine rides above the dot as well. My electric gauge shows about 185. Both are irrelevant though since the gauge can be adjusted. I installed a koyo as well, with a not clutch fan. All depends on what your water pump situation is. In any case you'll want the fan and shroud.. or just run two small electric fans. On the highway my car is around 160 on a cold day, 170 on a warm day.

[racerx]

No clutch fan on mine, no shroud, no electric fan. Tstat is 160 and on hot days it will be around 170.

[Roadster-ka]

Can't go wrong with the Koyo and electric fans. My LZ 2.3 runs a 180 stat and doesn't get above 190 on 100 degree day in traffic.

[heywier427]

Thanks for the welcome!

 

As for the pictures, what do you want to see?  Here is what I am thinking...

 

Picture of the temp gauge

Picture of the current setup

 

Let me know if this is what you mean.  Also, and since I am new, is the only way to post a picture by a url?  We can't attach a jpeg, bmp?  Thanks!

 

Best way imo, to post pics is upload to flicker, then click share, then click bbc code, then copy the link and paste it into the post.

 

Dont really care about pictures of your gauges or wiring, thats boring,  just post pics of the car.   :rofl:

[LenRobertson]

In my '72 510 I run a stock L20B and the original radiator from when it had a 1600 with clutch fan and no shroud. It's run here in E WA in above 95F temps with no boiling over. BUT, that is out on the highway. I suspect if It got over 100F or I ever drove in traffic, I'd likely be in trouble.

 

If you want to go back to a clutch fan you will probably need to buy a new water pump with clutch since it is pressed onto the pump shaft (unless you still have the clutch and the PO just removed the fan blades). If you get a new pump the common wisdom says to be sure to get one with a cast iron impeller, not a stamped metal one. I looked on line and most I found had the stamped metal style. I finally ordered one through local auto parts with cast iron impeller.

 

Also be aware there are different bolt patterns for the plastic fan blades so you need to find the right blades for your clutch fan. I know there are at least two, probably more, bolt spacings.

 

I suspect replacing your electric fan will be cheaper and easier. And may give you better cooling in traffic. Installing a thermostat switch on the fan is probably worthwhile but I've never run an electric fan on any vehicle so someone else may have a better idea on the need for a fan thermostat.

 

Len

[datzenmike]

If you have a fan on all the time then what's the point of removing the mechanical one? Previous owners are the dumbest shits. It should have a thermostat switch that turns the fan on only when needed. Got to figure, the first 5-10 minutes engine is cold. If on the highway, vehicle speeds does most of the cooling effort. (rant over)

 

Fan location behind rad is OK as long as fan is not blowing air forwards.

 

Usually Datsun engine temp gauges had a 'run range' clearly marked. Anywhere in this range is ok but I try to run just below half. The driver is expected to notice when the engine suddenly changes it's usual reading to alert him something is wrong or different. All Datsuns I have had run about the middle of this 'run range'.

 

 

 

Running hot...

 

Be sure the rad is not blocked by leaves and debris on the front that restricts air flow. Are the fins clear? Fog lamps? Grill

Are the heater hoses connected together because the heater core leaks? This heater water bypasses the rad so plug both hoses and stop the flow.

Rev engine high and watch the bottom rad hose. If softened from age, it can collapse from pump suction and restricts flow on the highway.

Check engine timing. Retarded timing dumps huge amounts of waste heat into the exhaust ports and the water around them.

Block any openings in the rad support or around the rad that are not used. A piece of rubber floor mat can be attached to the under side of the hood across the top of the rad support also, to keep air from getting through between them.This dams the air up in front and forces it through the rad.

 

 

Always run50/50 anti-freeze water mixture.

Add a coolant recovery rad cap and collect all overflow so it can be returned to the rad when it cools. 

Paint the rad flat (not shiny) black. Flat black radiates more heat.

[sgplancer]

Well thank you everyone!  To comment on some of the feedback...

 

Mechanical gauges....  I agree.  I know that any gauge can be "manipulated" to read whatever you want.  I just want an accurate one.  My plan is to add something so that I am not relying on a 50 year old temp gauge.

 

Previous owners are the dumbest shits..... I agree!  One of the previous owners installed a "kill switch".  It basically was some speaker wire run from a toggle switch under the dash to interrupt one of the terminals on the coil.  What the hell?  I removed that right away.

 

It should have a thermostat switch that turns the fan on only when needed...  That is what I plan to do with the extra fitting on the Koyo radiator.  This would be if I didn't go back with a mechanical clutch.

 

Fan location behind rad is OK as long as fan is not blowing air forwards... It isn't.  It is blowing across the radiator.

 

Running hot...  Not sure if it is.  This is why I asked what people are typically seeing on their gauge readout.  Granted, the gauge is mine was only on the 68 and 69, I figured I would ask.

 

Be sure the rad is not blocked by leaves and debris on the front that restricts air flow... Done

 

Are the fins clear?  Yes

 

Fog lamps? Grill  Yes and Yes

 

Are the heater hoses connected together because the heater core leaks?   No

 

Rev engine high and watch the bottom rad hose. It is new.

 

Check engine timing. On my list of to do items.  I need to research and see what timing needs to be set at as well.

 

Block any openings in the rad support or around the rad that are not used.  Already done.

 

Always run50/50 anti-freeze water mixture....  I agree

 

Add a coolant recovery rad cap and collect all overflow so it can be returned to the rad when it cools...  It has an overflow bottle, but I don't know if it has a tube going to the bottom of the bottle.  I will check into that!

 

Paint the rad flat (not shiny) black. Flat black radiates more heat..... Will keep that in mind for the Koyo.  

 

Again, thanks guys.  

[datzenmike]

I wasn't clear. If the fan is behind the rad it must suck air through the rad., front to back.  If in front it must push air through the rad from front to back.

 

New hose doesn't matter. Check and be sure. Many lower return hoses have a coiled spring inside to brevent it collapsing.

 

 

 

To be absolutely sure of temps, get or borrow an infra red gun and 'shoot' the thermostst housing for the true reading. Look at your 50 year old gauge and see where it is. If you read 185F or so and the gauge is about 1/2 that's where you can run safely. Just yesteday I climbed a long long hill in 5th and the gauge went about 3/4 of the way up into the 'run range' while concerning, there was no problem. Im going to look into this more when I get home. I also have an electric fan that comes on just about 1/2 or just above. Normally it never comes on on the highway.

[Lockleaf]

If you can get your hands on an infrared thermometer you can test engine temp that way to check your gauges accuracy.

[sgplancer]

I wasn't clear. If the fan is behind the rad it must suck air through the rad., front to back.  If in front it must push air through the rad from front to back.

 

New hose doesn't matter. Check and be sure. Many lower return hoses have a coiled spring inside to brevent it collapsing.

 

 

 

To be absolutely sure of temps, get or borrow an infra red gun and 'shoot' the thermostst housing for the true reading. Look at your 50 year old gauge and see where it is. If you read 185F or so and the gauge is about 1/2 that's where you can run safely. Just yesteday I climbed a long long hill in 5th and the gauge went about 3/4 of the way up into the 'run range' while concerning, there was no problem. Im going to look into this more when I get home. I also have an electric fan that comes on just about 1/2 or just above. Normally it never comes on on the highway.

The fan is in front of the radiator, and is blowing air across the radiator fins.  It is not between the radiator and the motor.

 

I will borrow an infrared thermometer from work and check the housing temperature.  Didn't even think of that one and I work in a chemical plant!  Thanks.

[edekalil]

Welcome to the forum.