G'day

My 79 280zx has been running hot for some time, to the extent that often after not more than a 5-10 minute drive you can hear the water boiling in the radiator/overflow tank, and it has also been bursting the radiator hoses, both the major ones and smaller ones.

I was told that I needed a new radiator core, however have instead sourced a radiator from a wrecker, have also replaced most of the hoses, and also the thermostat. (For the record, the old radiator was not in great nic, maybe 1/6 of the fins damaged at the lower end)

Took the car for a spin... after less than 5 minutes the temp gauge was at Max.

At this point all I can think is to instal a new water pump. I did notice that the water did not appear to be churning all that much when I looked inside the radiator...

Is there anything else I could be missing?

The odd thing... despite the gauge reading MAX, this time there was no boiling sound....

cheers

Travis

 

Make sure you have oil in there!
New thermostat is a first but you got that. Make sure its a 180deg stat since you're having problems.
MOST of the time I would say its just the radiator itself. A junk yard radiator may have been good, but the gunk in it could have been setting (maybe rusting) for a few years while in the yard. Have your radiator flushed or just go out and buy a brand new radiator. I had intermittened overheating problems. I just went out and bought a new radiator 5 years ago and have never had a problem since then.

yes, the water pump could be it but probably not. Usually if those go bad, its the seal at the pully shaft that goes out and they start leaking water like crazy.

Double-check the thermostat. Was it installed upside down?

If you do decide to buy a new radiator, check the prices of an OEM steel radiator vs. the generic aluminum radiators sold by Summit Racing online. They are not that bad in price. They do require some custom mounting points, but they look cool and cool very well.

 

Bleach is absolutely correct. Unless you spent the money to have the junk yard radiator flushed and pressure tested, you didn't get a very good deal.

An OEM radiator can run as little as $125 wholesale add another $25 to $50 for retail and you're looking at $175 + shipping.

I went with an aluminum radiator from Jags That Run that was designed for ZX V8 swaps in a complete kit for $280. This thing never gets more than luke warm unless I'm running the turbo at high boost for long intervals... ie. Blasts down I5!

In town or on the highway at a leisurely pace I barely have to run the fan.

Mike sells the kit that is bolt on with the only need to move your AFM about 3/4 inch over to clear the new hose. It also has an integrated tranny cooler if you have an automatic but you can also use it as an external oil cooler if you have a 5-speed.

https://shell7.tdl.com/~jags/Pages/P...iator_Kit.html

 

How big is the stock radiator? I don't have my Z right here now...
You can get this guy (biggest one for the price) for $189 from Summit
19in high, 31in wide, 3in thick. Listed as circle Track Griffin radiator.
Part # GRI-1-26272-X


I saw at the Blue Lake Datsun show two 280ZX turbos running a very big aluminum radiator with no fan at all. The owners said they never need a fan. It stays cool enough even in traffic.

 

It almost never makes sense to go with a junkyard radiator over a new one. The cost of a new one is just too low to justify "going cheap" on a used one. As for the thermostat... If you bought it from anywhere other than the local Nissan dealer, it's wrong. The OEM Nissan t/s has a small bypass hole in it that none of the aftermarket units do. It does make a difference. It is also how your temperature sensor gets coolant to circulate through it before the t/s opens (giving you accurate readings). I have seen countless Z's that were reading hot, but not actually running hot because the t/s had no bypass hole.

Rod.

 

I've seen the common (Stant?) thermostats up to 180 deg have no bypass hole. The 192 deg thermostat I bought had the small bypass hole with a little metal doohicky hanging in the hole.
For my truck, it has a smaller radiator and is prone to overheating and then cooling back down to normal temp. I just drilled a tiny hole in the flat part of the 180 deg thermostat to slightly slow down the warmup process. I didnt' know that would help the gauge read more accuratly.

 

Also while checking out all the above check your fan clutch, do you hear it engage when its hot?

 

theres a guy over here in cali, i went to his house to get headlight covers. He was selling a 4 row radiator for 100, its pretty much new, i saw it with my own eyes
FYI :hpydance: