over heating

[jaynez31]

hi all, after I installed clutch slave and master cylinder, my 72z runs again. However, I encountered another problem, Over Heating.

After I drove my 72z (with L28 and 5 speed), I realized that water temp gage's needle showing above 3/4 which over 200 degree while driving highway about an hour with 90 degree Solano county, California. Then I drove through the city traffic(stop and go), the needle in the water temp gage showing almost 250 degree. When I came home, water temp indicated about 250 degree.

So, I parked the car left the idel running the car to see any leak from cooling system, I did not see any steam coming from anywhere but the water temp went over 250 degree, then engine gredually stalled.

Since my Z does not have Fan Shroud and radiator overflow bottle might caused over heat? or radiator or thermostate need to replace? Fan shroud not being installed? Air/fueld mixture?

Timing advance(my z does not have advance vacume)?

What would you recommend?

Shall I go for Electric Fan? or getting shrud?

My next question is: What's year's radiator shall I order? my 72 model year or my engine year 79-83 zx radiator?

jaynez31

[sblake01]

How's your Thermo-coupling (Fan clutch)?

[panchovisa]

Start with a new thermostat and hook up the over flow coolant tank.

[jaynez31]

Ok, folks, I picked up the thermostate from the local nissan dealer this morning, and I just installedf the thermostate this evening. I will take a test drive tonight or tommorow evening due to my job.

Anyway, couple weeks ago I (muffler shop) installed 2feet long resonetor just below the down pipe or 3 inch from the end of the header. It might constrict air flow, but should not be over heat right?

Another thing I need to add: 1. motor was remanufactured by Nissan only 25.00-30.000 miles on by Japan car club in Dublin. Head is P 79 and performance cam installed by Japan car club. when I looked the thermostate housing was pretty rusty.

The radiator is looks old.

I replaced water pump 3 weeks ago.

the fan is plastic and works OK.

Anyway, hopely, the thermostate may fix the overheat problem.

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just like 240z, I am from Japan too, what's heck

[jaynez31]

:mad:

Ok, After I installed the thermostate, I just took a test drive about an hour. During free way, the needle in the gage points 75% or 3/4 of the water temp gage between 120-250 marks. So, I caluculate 220 degree.

Tonight, Solano county's current tempuraure is 83 degree.

while city and idling, the needle points 85-90 % of between 120-250 the water temp gage marks, I would say235-240 degree, but it did not reach the 250 degree(redline) which yesteraday did over 250 degree. During the idling, engine did not stall.

It is better than not install new thermostat (170 degree open).

I hope someone has an advice to reduce the water temp, I would say, will 180 degree.

thanks,

jaynez31

[Razor]

how about a simple radiator flush? get those radiator flush liquid follow instrcutions

(its just draining your radiator to clean all that $^!# in there might solve the problem....)

[ZmeFly]

See whats going on, you are definetly running to hot and if you continue to do so you will eventually cause engine damage.

Look at the fluid in your radiator, see if it is circulating. Do you know the condition of your water pump, radiator? Has the coolant been changed recently, is it 50/50 mix.

Something is amiss, check each system and find out whats going on. An easy fix can become a real pain if you keep driving with the temperatures so high.

[LanceM]

I would check the accuracy of the gauge, maybe the sending unit is going bad and you are seeing much higher temps than are really there! I'd install a cheep mechanical gauge and drive around the block a few times and see what it says.

[zeiss150]

Hey Jay, If you changed your water pump and your thermostat and your still over heating like that you probably have a crapy radiator. You could try a nice radiator flush but 20+ years of old anti-freez can plug it up really good. Get a nice 3 or 4 row radiator on ebay for about $150 buck or so. I also wouldn't let my engine run at 250+ degrees, that sounds like a recipe for a seized engine. I replaced my radiator with a 3 row from ebay and it never gets above about 170 degrees.

Rock on Z People

Matt-

[jaynez31]

Ohh, folks, thank you for important feed backs. I feel way better the 240z.

Yes, the radiator looks old and some fins(I don't know what's call the small vents fins are damaged which air may be hard to go through.

OK I will buy the 3/4 core radiator probably this week end.

I will let people know what would be happen.

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just like 240z, I am from japan too, what's heck.