California Datsun Engine Overheat Season

[Boaty]

This topic comes up at least once a year. It's summer, and it gets hot in summer. Next year, plan ahead.

If you're overheating... which I don't really conclude that 205F is "overheating", just running a little warm (Hello, it's over a hundred outside!)... then it's generally due to cooling system inefficiency.

So here's my take. Assuming your radiator is good, and you're running without a thermostat - here's a suggestion. Replace your thermostat. Without one, in the winter it will never reach running temp, probably not even at idle, depending on outside ambient air temperature. In the summer, you'll likely overheat because water never gets a chance to cool down in the radiator. It doesn't look it, but without a thermostat - and high RPM's, that water can start flowing pretty quick. If it doesn't have a chance to have any heat transfer, well, then you're going to slowly get to the point it'll over heat. More so at higher RPM's at a steady speed, such as the freeway. If it were true that running no thermostat was the ultimate solution, we wouldn't have thermostats in every driven vehicle from before Datsun was a tickle in some Asians' penis. Or any other make for that matter. Replace your thermostat. On L's I run 180 in the summer (or 165 if you really wanna), and 195F in the winter (I like my heater.)

 

If your radiator is bad, this is just bad all around and requires service. The cooling system has to maintain up to a certain pressure, hence why you have a pressure rated radiator cap, to regulate it. If you're running zero pressure, your boiling point is much lower than if it were at higher pressure. Your Datsun (and most vehicles) will enjoy the standard adopted 13PSI. If you go higher, yes, it'll raise the boiling temp - but you're also going to raise your probability of blowing out other features of the cooling system. Such as the heater core, all associated and pressurized hose and tubing, and even your radiator.

Now in regards to the coolant/water ratio... 50/50 was adopted as pretty much the best you're going to get with average temperatures. Where temperatures frequently dip, or reside well below freezing (You Canucks) then your ratio should increase with a maximum of 70/30. A 10/90 ratio of coolant:water is very thin, this is going to drop your boiling point down to a temperature where it could likely boil in the heat, even more so if you're running an unpressurized system (pinhole in the radiator, anyone?). The coolant is there to raise boiling point, add lubrication, and as an anti-corrosive agent. Water wetter is good, it reduces surface tension and helps eliminate surface boiling. Meaning no bubbles that form and affix to surfaces that are hot enough to cause boiling.

 

I would run 50/50, because it's simple easy and fool proof. I use premix because I'm lazy as shit. But you can use whatever - just make sure you run DISTILLED water, not tap water (this includes city water). This is what causes corrosion to begin with. Mineral deposits from using tap water is probably the number one killer of cooling systems. It erodes aluminum (ever check the water jackets on these old L-series heads? Rare not to see corrosion damage). It corrodes copper (Ever look inside a copper water pipe, or,.. um.. your radiator? The white/blue oxidation is calcium and lime buildup from your tap water). And of course water by NATURE creates rust on iron and steel.

 

Ignoring a pin hole and running to thin a coolant ratio is just certain to cause bigger problems down the road. Not to mention you're going to leak/consume coolant, more so in summer - and you're going to get an air bubble, which is going to cause you to be on the side of the road somewhere with the hood up, and inevitably back here on Ratsun to tell us about it.

;)

[HRH]

This is just a dumb question, but I have to ask it.  You are using a 50/50 MIX of antifreeze and water, right?  I've seen some people put in straight anti-freeze, which has no cooling effect whatsoever.  Water is what cools.  In fact, you can use straight water if you want, but to raise the boiling point, you need the appropriate mix of both.

 

Boaty, I'm calling bs on the distilled water.  Is it better?  Yes.  Is it necessary?  No.  The block is iron, the head is aluminum, there are all sorts of minerals drifting off the block/head internals that will contaminate the distilled water anyway.  I've never used distilled water in any of my motors, and not once have I had pitting or cooling system failures.  Flushing the system every three years is a lot more effective for removing crap.  It's just no one ever does that.

[Dawa]

distilled is better than tap water in the very long run  but if you keep up on the maintenance "it isnt so bad."

also idk if yall have read, but they are now saying that reverse osmosis water is even better than distilled.

i read that recently in some car mag, it was at the suggestion of a major US radiator manufacturer. 

[Guest roseyroseyrose]

This topic comes up at least once a year. It's summer, and it gets hot in summer. Next year, plan ahead.

 

If you're overheating... which I don't really conclude that 205F is "overheating", just running a little warm (Hello, it's over a hundred outside!)... then it's generally due to cooling system inefficiency.

 

So here's my take. Assuming your radiator is good, and you're running without a thermostat - here's a suggestion. Replace your thermostat. Without one, in the winter it will never reach running temp, probably not even at idle, depending on outside ambient air temperature. In the summer, you'll likely overheat because water never gets a chance to cool down in the radiator. It doesn't look it, but without a thermostat - and high RPM's, that water can start flowing pretty quick. If it doesn't have a chance to have any heat transfer, well, then you're going to slowly get to the point it'll over heat. More so at higher RPM's at a steady speed, such as the freeway. If it were true that running no thermostat was the ultimate solution, we wouldn't have thermostats in every driven vehicle from before Datsun was a tickle in some Asians' penis. Or any other make for that matter. Replace your thermostat. On L's I run 180 in the summer (or 165 if you really wanna), and 195F in the winter (I like my heater.)

 

If your radiator is bad, this is just bad all around and requires service. The cooling system has to maintain up to a certain pressure, hence why you have a pressure rated radiator cap, to regulate it. If you're running zero pressure, your boiling point is much lower than if it were at higher pressure. Your Datsun (and most vehicles) will enjoy the standard adopted 13PSI. If you go higher, yes, it'll raise the boiling temp - but you're also going to raise your probability of blowing out other features of the cooling system. Such as the heater core, all associated and pressurized hose and tubing, and even your radiator.

 

Now in regards to the coolant/water ratio... 50/50 was adopted as pretty much the best you're going to get with average temperatures. Where temperatures frequently dip, or reside well below freezing (You Canucks) then your ratio should increase with a maximum of 70/30. A 10/90 ratio of coolant:water is very thin, this is going to drop your boiling point down to a temperature where it could likely boil in the heat, even more so if you're running an unpressurized system (pinhole in the radiator, anyone?). The coolant is there to raise boiling point, add lubrication, and as an anti-corrosive agent. Water wetter is good, it reduces surface tension and helps eliminate surface boiling. Meaning no bubbles that form and affix to surfaces that are hot enough to cause boiling.

 

I would run 50/50, because it's simple easy and fool proof. I use premix because I'm lazy as shit. But you can use whatever - just make sure you run DISTILLED water, not tap water (this includes city water). This is what causes corrosion to begin with. Mineral deposits from using tap water is probably the number one killer of cooling systems. It erodes aluminum (ever check the water jackets on these old L-series heads? Rare not to see corrosion damage). It corrodes copper (Ever look inside a copper water pipe, or,.. um.. your radiator? The white/blue oxidation is calcium and lime buildup from your tap water). And of course water by NATURE creates rust on iron and steel.

 

Ignoring a pin hole and running to thin a coolant ratio is just certain to cause bigger problems down the road. Not to mention you're going to leak/consume coolant, more so in summer - and you're going to get an air bubble, which is going to cause you to be on the side of the road somewhere with the hood up, and inevitably back here on Ratsun to tell us about it.

 

;)

im not ignoring the pinhole, im just trying to get by until i can afford to have it fixed. my truk is the only thing i have to drive, and i have to work, so im doing what i can to get around...thats what i get for being an artist in tucson, alas......

[datzenmike]

I heartily agree with Boaty on everything except the water going through the rad too fast to cool it. If the water temp is 200F and the moving air is 80F then X amount of heat will be drawn away. Weather the water inside is moving at 10 MPH or a thousand MPH the same amount of heat will be removed.

[HRH]

Damnit, you mean I'm going to have to disagree with Boaty AND Datzenmike in the same thread? Lol.  The argument for coolant moving too fast to heat-exchange efficiently is valid.  That said, most Datsuns can run without a thermostat in 50-70 degree weather and they'll never heat up.  BUT, add 100 degrees, and yes, the coolant can't stay long enough in the fins to have heat sucked off.  It's like walking by a big fan, or running by a big fan.  The longer you linger, the more the heat exchange.

 

You CAN however, run without a thermostat and be heat-exchange efficient by removing the spring assembly from the thermostat, and just using the plate with the restrictive hole in the center.  This further proves the heat exchange issue (only in hot climates where it matters, though it is 100 degrees here today.  Bleh.) as the interior dimension that opens up on a 54mm thermostat, is barely 19mm of actual opening.

 

I still stand by my water argument.

[Boaty]

I am used to being disagreed with, so it's okay. I know several people that say their oil is perfectly fine and never needs to be changed, the filters are the only serviceable part and that oil need only be topped off when necessary. Big oil runs the oil industry, anything to make you change it more often,... right? :thumbup:

If you use hard water, and spray it on your house window in the sun, let it dry. That is one application of water spots. Do this a few more times. In fact, go look at your shower door (assuming you have a glass shower door). Betcha it's water spotted up. Distilled water won't do that, because it's distilled water. It doesn't have the concentration of minerals that tap water does.

Being fair, with what you said, it doesn't matter if you use distilled or not because contaminents from the block and/or head will contaminate the coolant anyways. Theoretically, I guess that's true. But I blow my nose in tissue and it contaminates the tissue. But I sure as hell don't wipe my ass with it first before I blow my nose, or vice versa. If somebody is going to go through the motion of replacing a radiator and a thermostat, probably the hoses, give it a nice good flush (assuming they are thorough), the very last thing I am going to do is advise them with bad advice. Besides, a .69 for freakin Distilled water at wally world, or even better - skip that and just run 50/50 pre mix and never worry about the measuring part of it.... dont' even have to worry about the distilled anything. :)

 

I used a similar example to a buddy that recently refreshed his brake system. New calipers, rotors, pads, the whole nine yards. Spent the extra money on brembo rotors, extra money on new calipers instead of remans... and bought the cheapest brake pads he could buy to 'save money'. Orrr he could just spend a little more and get good brake pads instead of wasting all the extra money on good shit to be used with teh worst shit he could get. His pads smelled like piss and tar and were crumbly before they ever got taken out of the box.

YMMV.

[datson4life]

nice! thanks for all the info fellas, ratsun has been good to me, even when im broke down on the side of the road ive contacted ratsun fellas and got parts to get me home no matter where im at, who needs AAA tow services when u have ratsun.............i will read through all responses again tomorrow and start working on solving the issue this weekend when i get some time.

 

i am running pretty rich, the belt hasnt been as tight as it should be, and i need to put a thermostat on.....

zeusimo lives the next town over and he is running at 180 degrees in this weather, i wanna do that :crying:

[Boaty]

And about the thermostat. Why not just run the correct thermostat... if your cooling system is up to snuff and isn't fubar, it should be able to cool everything just fine so long as you have proper air flow, it holds pressure, you have the correct mix of coolant and water, and your engine is sound. It is, afterall, designed to keep the engine at or around a certain temperature. Without one your temps will be all over the place, and as previously expressed in this thread - is going to throw off how the engine runs.

If everything is running like it should be, you could run whatever thermostat you'd like and never have a problem.
Stock KA24DE thermostat is 160F. I run a 195F, and it was 106F here in Grants Pass today. I sat in traffic, temps were around 200 until the fans kicked on, dropped down to 190-195F as expected. Cooling system up to snuff, doesn't overheat, even with a +35F thermostat. :)

[Boaty]

nice! thanks for all the info fellas, ratsun has been good to me, even when im broke down on the side of the road ive contacted ratsun fellas and got parts to get me home no matter where im at, who needs AAA tow services when u have ratsun.............i will read through all responses again tomorrow and start working on solving the issue this weekend when i get some time.

 

i am running pretty rich, the belt hasnt been as tight as it should be, and i need to put a thermostat on.....

zeusimo lives the next town over and he is running at 180 degrees in this weather, i wanna do that :crying:

 

 

180F is a good choice. Decent enough for winter (especially in Modesto) and perfect for summer. If you lived in Arizona or something, 160F would be just fine, too. I would vote for 180F myself. That's what I ran.

 

195F is for when you freeze your ass off in winter and want some heat.

160F is for when you don't have a heater and you can fry eggs on the sidewalk.

180F is for 'Murrica.

[Boaty]

BTW.

Yay tap water!

 

Don't even get me started about electrolysis....

[datson4life]

i forgot to mention i always pump 91 gas due to running a peanut head, ive heard and dont know if its true that the higher octane gas produces a higher temperature?

 

and i have full antifreeze, no water

[Boaty]

Umm... there is your problem.

Antifreeze has almost no cooling capacity. Which is why it MUST be mixed with water.
You're GOING to run hotter without water in your antifreeze. Go fix it. Do it.
 

Here's some e-Literature for ya.

http://www.castrol.com/castrol/sectiongenericarticle.do?categoryId=9045298&contentId=7080655

 

http://www.eetcorp.com/antifreeze/antifreeze-about.htm

 

http://www.eetcorp.com/antifreeze/antifreeze-about.htm

 

 

http://www.challengers101.com/CoolantMix.html

 

 

http://www.ehow.com/how_2188874_mix-car-coolant.html

[Boaty]

Oh and the gas thing doesn't really make any difference at all.

All the octane reading does is suppress detonation from compression and heat. Higher octane fuel doesn't ping at X compression. Hence why high performance (high compression) and turbo engines require higher octane, becuase at higher combustion pressures, you build heat (think intercoolers here)... thus causing you to ping.

Assuming detonation and preignition are exempt from calculation, octane level will have nil to zero effect on power or heat. I run 91 in my car, because with 87 it runs like butthole because it retards timing, due to ping. ;)

[Ranman72]

full antifreeze is no good unless your mistaken and it was the pre mixed kind

50 50 mix is standard

[datson4life]

no im not mistaking, i got full antifreeze :blush:

i will fix that in the morning

[HRH]

Haha, don't feel bad, I've heard that a million times.  

 

And yes, Boaty, I will agree with electrolysis and deposits.  We sell a NAPAkool conditioner for heavy trucks to skirt that problem.  Of course, diesels have a lot more issues with that than our Datsuns.  And GM has way more issues (had) with deposits and corrosion, hence their brilliant idea for dexcool.  In a GM, I would absolutely use distilled water.  But then, I wouldn't own a GM if my life depended on it.   ;)  Go Ford!

[datson4life]

i dont feel bad, maybe a bit embarraced cause it seems like im the only one alive that always thought going full antifreeze was how to do it right, my cool level dropped

[Komeuppance]

Your cool level went up, I've done it when I did my first coolant change years ago lol.

 

-Robert

[captaingamez]

I am used to being disagreed with, so it's okay. I know several people that say their oil is perfectly fine and never needs to be changed, the filters are the only serviceable part and that oil need only be topped off when necessary. Big oil runs the oil industry, anything to make you change it more often,... right? :thumbup:

 

If you use hard water, and spray it on your house window in the sun, let it dry. That is one application of water spots. Do this a few more times. In fact, go look at your shower door (assuming you have a glass shower door). Betcha it's water spotted up. Distilled water won't do that, because it's distilled water. It doesn't have the concentration of minerals that tap water does.

 

Being fair, with what you said, it doesn't matter if you use distilled or not because contaminents from the block and/or head will contaminate the coolant anyways. Theoretically, I guess that's true. But I blow my nose in tissue and it contaminates the tissue. But I sure as hell don't wipe my ass with it first before I blow my nose, or vice versa. If somebody is going to go through the motion of replacing a radiator and a thermostat, probably the hoses, give it a nice good flush (assuming they are thorough), the very last thing I am going to do is advise them with bad advice. Besides, a .69 for freakin Distilled water at wally world, or even better - skip that and just run 50/50 pre mix and never worry about the measuring part of it.... dont' even have to worry about the distilled anything. :)

 

I used a similar example to a buddy that recently refreshed his brake system. New calipers, rotors, pads, the whole nine yards. Spent the extra money on brembo rotors, extra money on new calipers instead of remans... and bought the cheapest brake pads he could buy to 'save money'. Orrr he could just spend a little more and get good brake pads instead of wasting all the extra money on good shit to be used with teh worst shit he could get. His pads smelled like piss and tar and were crumbly before they ever got taken out of the box.

 

YMMV.

you are right on about the distilled water,

 

 

but a side note on the oil thing, people have used Amsoil  oil in trucks for many many years, and never changed their oil, they have also done consistent OA (oil analysis) to determine the state of the oil. there are people who have ran the same oil for 200,000 miles only changing the filter and adding a quart every 25,000, after inspection of some of these motors upon disassembly they were found to be in almost new condition.

 

dont believe me? do you own research.

 

I change mine at around 6-7000 running mobile 1, with oil analysis, the oil is actually analyzed as still being good when I take it out of my car. my last engine lasted my 260,000 miles of hard driving and racing. And I know people who have blown up the same engine daily driving for 200,000 miles with regular 3000 mile changes, the head gasket went by the way, and the car still ran great, which is the first time that has happened to me ever, but im pretty sure the headgasket isnt oil related.......

 

I wouldnt EVER do that shit with regular oil though, regular oil actually breaks down, Synthetic FTW.

[HRH]

You do realize of course that synthetic oil is still 75% conventional oil base, right?  You can't have a 100% full synthetic oil, it doesn't work.  Yes, it's better, but it will still break down over time/heat cycles.

[captaingamez]

where are you getting your information, because that is entirely incorrect as far as I know.

 

Not saying your definitely wrong, but I have never read, or been told that, ever, can you back it up?

 

everything I have ever read is exactly the opposite of what you just said.

[72240z]

Thats yet another myth as I understand it. I have heard lots of people say that synthetic oil is derived in some way frome crude or that synthetic is nothing but used oil lol etc...

Synthetic oil is created using the Ficher-tropsch procedure which came about in WW2 when oil was hard to come by. It uses base materials to create synth, not crude oil. Now if some companies do or did cut their synth with conventional or some shit thats a different story. 

[HRH]

I get that information from my Schaeffer's oil rep.  I'll have to give him a ring so I can regurgitate it correctly.  But basically, you don't need much synthetic oil in the base oil blend to do a good job of lubrication.

[datzenmike]

Damnit, you mean I'm going to have to disagree with Boaty AND Datzenmike in the same thread? Lol.  The argument for coolant moving too fast to heat-exchange efficiently is valid.  That said, most Datsuns can run without a thermostat in 50-70 degree weather and they'll never heat up.  BUT, add 100 degrees, and yes, the coolant can't stay long enough in the fins to have heat sucked off.  It's like walking by a big fan, or running by a big fan.  The longer you linger, the more the heat exchange.

 

I still stand by my water argument.

.

Matt you're a gentleman and arguing with you a pleasure. At the worst we will only agree... to disagree.

 

OK don't forget that it's not a single drop of water but a moving conveyor belt of water flowing through the rad. YES it's there a shorter time and sheds a small amount of heat but over say a timed minute a lot of water will pass there ridding lots of small amounts of heat. Overall it will add up to the same amount.... either a quart cooled a lot (and then diluted in another 8 quarts of very hot water) or all 9 quarts cooled slightly.

 

I'd be willing to bet that the faster flow will cool even more as the rad will be hotter and heat loss is greater when the temp difference is greater between rad and the air going through it.