Radiator mess !

[Pacific coast Datsun]

Ok last week im driving the 521 & i notice the temp gauge getting warmer as im driving to work & then it started sputtering-backfiring & missing! I pulled over & the problem went away & off to work i went. The next day I checked it out & saw this..........

Turns out the upper hose clamp wasnt tight / not at the end of the hose & water was leaking & spraying right under the dist. cap getting the points wet! So today I decided to pull all the water hoses off to check em out & holy crap the 1 hose coming off the lower water jacket & 1 of the heater hoses were clogged with what looked like rusty-chunky s**t !!!

I blasted it out with the water hose & also the radiator until the water ran out clear..reinstalled everything & it's running a bit cooler now & my heater actually blows out hot air now :D This truck doesnt have a fan shroud either so ill prob. check the yards or make my own then swap in a new thermostat & rad. cap & i should be good for the summer.

[Bleach]

nasty stuff.

I found that I really needed the fan shroud on my 4-cyl L-series radiator.

The Z does fine without one.

[Icehouse]

wow that is some nasty goo!! You can still buy the heater hoses new from nissan, I think they are under 20 bucks for both. I bought 2 sets for a 521 and 1 set for a 510 less than a year ago.

 

Its funny how some cars need the shroud, my 1200 needs one.. Maybe its because the fan is at least 6" away from the rad.. :D

[Cookapoop]

 

 

eeeeeeeeeewwwwww!

[Pacific coast Datsun]

Ok yeah this is wierd..now the last 2 times i drove the truck the temp. went way past the halfway point! Up until i "fixed" the problem it would stay at halfway. I noticed the leak @ the radiator is still there but not too bad. I can tell because the water is dirty [rust colored]. Wierd thing...i checked the water level after work tonight & it was right at the top of the rad. Im hitting the yards tomorrow for a shroud, hopefully ill find the right one. Pics to come...

[datzenmike]

I'll bet you find some of that crud on, in or near your thermostat and housing when you change it. Overheating will stir up sediment in the block (like steam cleaning), actually any where in the cooling system, and circulation will move it along to other parts.

 

NEVER use that stop leak crap! (not saying you did, possibly a PO) it just bungs up everything. The rad water will look like cafe' au lait with chunks that look like dead flies. Had a few cars where someone's put that shit in and the heater doesn't work very well until you flush it out. Once it was flushed out the rad started to leak a week later. It will also collect in the thermostat housing. Stop leak is for fixing a rad temporarily so you can get to a shop.

[Pacific coast Datsun]

Ok..today i had the leak in the radiator fixed [near top tube in upper tank] & installed a 180 degree thermostat. It got hotter than normal way faster now than before but when i hit the freeway it went down to right above halfway. I may have gotten a bad stat. or theres still some blockage in the rad. ? ! I did find a B 210 shroud which im modifying to work which should help keep it cool.

[Icehouse]

The shroud is for sitting in traffic, at highway speeds it doesn't need the fan or shroud....

[]2eDeYe]

I run (well ran and will be running again) the 160 degree thermostat. I loved how cool it keep the KC so much, I put one in my jeep ;)

[DISLEXICDIME]

i like the fail safe thermostat i just wish that they made them to operate at 160

[datzenmike]

IMHO If your motor is nearly stock or mildly done it should run at the temp it was designed to run at 185-195. This gives best economy/emissions/performance. In theory you should be able to idle, or full throttle, in 120 heat, all day and not go above the thermostat setting because the excess heat is being removed by the cooling system.

 

If you over heat at idle or full throttle applications, a 160 thermostat is a poor solution as it only works under severe conditions where the temp rises into it's proper range. At all other times, which is most of the time, it will be running at least 30 degrees cooler than it should. This often leads to condensation in the crank case that does not evaporate as easily. If your gauge goes up (over heat) in response to heavy throttle this is the an indication that your cooling system can't handle the job for some reason. Which could be:

 

Insufficient air flow. Is the belt slipping, clutch fan loose, did you remove the fan shroud and not put it back on, do you have anything in front that would restrict air flow like fog lights or license plate on grill, or dirt and bugs stuck in the rad? Is there room for the hot under hood air to escape?

 

Insufficient water flow. Is the water pump doing it's job and flowing enough water? Are the hoses old and soft causing them to collapse on the suction side (lower). Is the rad and cooling system plugged with scale and deposits?

 

Insufficient rad. Your rad was not intended to shed heat from an extra 20-40% increase in power, maybe not even 10%, so a larger rad might be in order. My old stock rad would run hotter or cooler by a few needle widths between city and highway and hard four wheeling. Not a problem but worrisome when I was off roar, I put a larger three core from an S-11 in it. The thermostat keeps the engine in it's running range and the rad gets rid of any extra heat. Just an opinion.

[]2eDeYe]

Even with the 160 degree t-stat I get to normal operating temp. It just takes a little longer and now my electric fan doesn't work nearly as hard to keep the motor at temp now.

 

Of course the best thing I did to my Jeep's coolant system was to get the proper radiator cap on there ;)

[Pacific coast Datsun]

D-mike TY for the info. What it's doing now is this..i warm it up for 3 minutes before driving it & it's roughly 3 miles to the freeway. In that distance the gauge goes up almost to the red...within 2 miles of being on the freeway it'll settle back down to halfway inbetween the mark on the gauge [halfway i suppose] & the red mark & stay right there. At idle it doesnt move. Newer water pump, 180 stat., water is flowing through the rad. & the PO claimed he had it rodded out plus i blasted water through it with all the hoses off [which may have helped], stock fan [no clutch], & a new fan belt. Today ill replace the rad. cap & within a few days install a "real" temp. gauge to see if it's running @ 185-195.

[banzai510(hainz)]

Pacific Coast

I like the stock senders myself.

The aftermarket ones its kinda a pain to find the correct fitting since most are NPT and the Jap use Britsh Pipe thread. So making if fit will cost you and probably will NOT fix your proplem.also making cracking your housing since most have never been apart!!!!!!!!!!I KNOW THIS ONE!!!!!!!!!!

I have a feeling. A FEELING that its the head gasket.

 

You could have the Rad tested for flow But if it heats up that fast I think its the head gasket. (armchair trouble shooter)

 

But replace the Cap also since its cheap

[datzenmike]

D-mike TY for the info. What it's doing now is this..i warm it up for 3 minutes before driving it & it's roughly 3 miles to the freeway. In that distance the gauge goes up almost to the red...within 2 miles of being on the freeway it'll settle back down to halfway inbetween the mark on the gauge [halfway i suppose] & the red mark & stay right there. At idle it doesnt move. Newer water pump, 180 stat., water is flowing through the rad. & the PO claimed he had it rodded out plus i blasted water through it with all the hoses off [which may have helped], stock fan [no clutch], & a new fan belt. Today ill replace the rad. cap & within a few days install a "real" temp. gauge to see if it's running @ 185-195.

 

Do you have a small bypass line from the thermostat housing to the lower rad hoes inlet? Without this hose there is no flow of water past the thermostat and the the engine can get quiet hot before the heat leaks out to the thermostat and opens it. It is usually a metal line beside the fuel line at the front of the engine with rubber lines to the thermostat housing and maybe the intake manifold.

[banzai510(hainz)]

datzenmike

My sidedraft equip cars do not have this waterline your talking about since the manifolds/lower bypass is not used and my cars DO NOT over heat.

 

He could alway drill a 1/8 in the sat but I dont think this will help

Can remove tthe stat and if this still gets hot(relative speaking with the stat out then Im looking at the head gasket. Unless the lower waterhose is getting squeezed whe the motor is reved up

[Pacific coast Datsun]

Mike, mine does not have this bypass hose you speak of. There is a metal line that runs from the base of the carb. to the top of the lower rad. jacket. Hainz i dont think it's a bad head gasket...the oil is still the right color & it has a good amount of power. The gauge now will stay put & doesnt climb up past that point. Im also driving it with the pressure release lever in the "up" position on the cap which may be helping or maybe not. Deff. a new rad. cap will be put on today & ill see how it does.

[banzai510(hainz)]

Pac Coast

I had a sender that worked and dindt work.I had to repalce it but the old one would not come out so I ordered a new lower stat housing and threaded ring to hold the new sender in.

 

As for the head gasket ,? It can still blow into the coolant which would overpressurize the system. But not go into the Oil.

Seen this on my old mans Toyota Cressida. Would get close to the RED then lower half way and do this all the time. swaped stat,cap ect to no avail.

 

When the system is pressurized normally the water will reach a higher temp before overheating butt if too hot the cap will blow at 12 ,13 pounds on a normal car/truck. This is my understanding.

[Pacific coast Datsun]

Hainz your input is appreciated..! Ok i put a new rad. cap [13 lbs.] on today & now the gauge wont go right up to the red as fast as before but instead it goes right up to the same location as before [halfway between halfway & the red]. I suppose this is gonna be ok for now. The rad. hoses look to be ok & not collapsing & im running a 60% - 40% ratio [coolant/water]. Hainz...if i drill a 1/8 hole in the stat. would that help cool it down a bit & where should i drill the hole?

[banzai510(hainz)]

Some 510/521s had a bypass. The water lines that went to the intake manifold to heat it. Some lines had a output the U around to the lower part of the stat housing. Im sure you seen this before. Some did some didnt. If you already have this bypass then dont worry about it. If you dont remove the stat and just drill into the flat part of the stat or remove that little jiggle valve and drill a 1/8 or a little bigger hole. This is just a last ditch resort to your proplem. But if thats a 30 your old head gasket it still could be it.

 

Make sure motor is timmed also and not too Advanced

 

i just wonder since you slightly overheated this in the first place then the gasket gave out on the inside?????

 

But Im out of awnsers unless you know that rad is good. But rads dont go bad all of a sudden. You know your truck, not us.You know if there was a SUDDEN CHANGE

 

But when I rebuilt my 1st L16 it would run Hot for a long time (But it was a new motor) now the temp is fine.

[Pacific coast Datsun]

Ok after dealing with this problem for a few weeks i finally got it under control. I had the leak in the rad. tank repaired & ended up just removing the thermostat altogether. The gauge in the hot daytime commute doesnt go above halfway. At night the needle stays on the line on the gauge [below halfway]. I cut off the jiggle valve but it didnt make a difference. You guys are very helpfull & appreciate the advice.

[raggmann]

wow that is some nasty goo!! You can still buy the heater hoses new from nissan, I think they are under 20 bucks for both. I bought 2 sets for a 521 and 1 set for a 510 less than a year ago. :D

 

Not to revive a real old thread but would anyone have the part numbers for the heater hoses on a '72 521?

Mine are gone on both my trucks.

My local stealer-ship is NO help if it's older than 2005 but I see them every now and then on ebay.

[Charlie69]

Pac you did not have this problem until you lost water/coolant do to a loose hose clamp. You then flushed the system with you garden hose.

 

When you flushed the system did you flush the block in reverse flow with the heater core & radiator bypassed?

 

When I flush my system I disconect all hoses and flush radiator, heater core, & block seperately. Also you must remove the thermostat before flushing in either direction.

 

What I am huessing happened is the flushing you did worked for the heater core but probably did nothing but deposit more debri in the block & radiator restricting the flow of the water. from the looks of the crap that came out I would have the radiator rodded out & have the system power flushed by a radiator shop if the EPA allows the power flushing in you area.

 

Remember that overheating is the #1 cause for blowing a head gasket.

 

Just my 2 cents.

[Nicholas7620]

Radiators wear out/plug up and rodding out/power washing doesn't restore radiator to new condition. Remove old radiator, thermostat and flush system until water is clear.

 

Install new radiator and antifreeze/coolant and engine will run cool. I was having same problem with erratic heat readings on my B210. Installed 160 degree thermostat which didn't help because radiator was too old to cool engine.

 

New radiator solved erratic heat readings. Heat reading now stays in the same place and doesn't budge regardless of driving conditions. The new radiator immediately cools down the antifreeze as the thermostat lets the hot coolant flow. The cold coolant is immediately available as the engine needs cooling.