# overheating problem



## 4wheelinbroncos (Mar 7, 2005)

I've got this problem with my 87 300zx It over heats at idle when under load. I've removed the fan clutch and replaced it with a direct drive fan, new radiator, new t-stat, new water pump.


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## Spongerider (Nov 18, 2002)

4wheelinbroncos said:


> I've got this problem with my 87 300zx It over heats at idle when under load. I've removed the fan clutch and replaced it with a direct drive fan, new radiator, new t-stat, new water pump.


Put back your fan clutch and see if the problem goes away.


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## 4wheelinbroncos (Mar 7, 2005)

The problem use to be anytime at idle, I changed the clutch and that didnt help so I tried the direct drive setup and now it only overheat wile under load at idle. Iam about ready to go with a aluminum radiator to see if that helps


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## 4wheelinbroncos (Mar 7, 2005)

Iam new to nissans, this car was free and I've been tinkering with it for about 9 months and about ready to give up cause of this overheating proplem and not able to find performance parts for it. JEGS, and Summit Racing have a great selection for the Fords (Ive got two Broncos, an F150 and a E350 van) but nothing for the Nissan. So where do you guys get performance parts for it.


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## Zen31ZR (Mar 24, 2004)

Over heats at idle, so then poor coolant circulation at idle, I'd first check and make sure your idle isn't too low. That would be the easy fix, 2nd on the list would be a new radiator. The 300ZX has a very small air inlet area for the radiator so any clogs inside or blockage outside the radiator (leaves etc) will cause problems that sometimes are not immediately apparent with other cars. Make sure the fan shroud is still in place, this affects cooling in a big way with the Z's, much more so than American cars. Japanese performance cars typically use small engine units and therefore there is much less room for error than American cars. 

Performance parts can be found, but certainly not in Jegs or Summit or any of the other places you are used to looking. The are also more expensive than your typical 302/351/460 engine performance parts. I know, I've had all those same engines myself and many others. Victoria-British is a good place to look for Z performance parts, though the prices are horrendous even by import standards. Other than that you'll have to hunt around. I'm sure some people here have useful links to some good parts.


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## Spongerider (Nov 18, 2002)

4wheelinbroncos said:


> The problem use to be anytime at idle, I changed the clutch and that didnt help so I tried the direct drive setup and now it only overheat wile under load at idle. Iam about ready to go with a aluminum radiator to see if that helps


You said you,
_"replaced it with a direct drive fan, new radiator, new t-stat, new water pump."_

The reason you should change back to the OEM fan is that non oem fans have different cfm/ drawing less air then stock. Also did you put the radiator shroud back on?


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## 4wheelinbroncos (Mar 7, 2005)

The new fan draws more air than stock and it got better when I went with the aftermarket setup. After installing the aftermarket setup it didnt seem to overheat so I took down to get to pass smog and it overheated on the dyno also I did reinstall the shroud. Ive got more problems getting this thing to pass than my 90 bronco (it sits on 36" tires with 7" lift and a strocked 302 giving me about 450hp)


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## Spongerider (Nov 18, 2002)

4wheelinbroncos said:


> The new fan draws more air than stock and it got better when I went with the aftermarket setup. After installing the aftermarket setup it didnt seem to overheat so I took down to get to pass smog and it overheated on the dyno also I did reinstall the shroud. Ive got more problems getting this thing to pass than my 90 bronco (it sits on 36" tires with 7" lift and a strocked 302 giving me about 450hp)


Have you flushed your system out? As for your after market fan I only suggested it could be the problem because no matter which aftermarket fan is used on a Z32 it has heating issue.


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## AZ-ZBum (Nov 21, 2004)

something is seriously wrong with your car then. if you've replaced those things and are still having issues, you're probably looking at a blown head gasket or worse.


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## Zen31ZR (Mar 24, 2004)

I'm thinking a water pump missing some impeller blades..... BHG's are fairly obvious. Any number of other stupid things, including an upside down thermostat or a pinched hose.


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