Datsun Roadster Forum-311s.org

Hi All, thanks for this valuable forum!

I'm trying to get a 1965 Roadster up and running as a gift to my dad- I've made a lot of progress but a little hung up here.

From what I can tell the car is a 1965 1500, with a 1600CC swap, including what looks like a 69-70 style cooling system, but minus the expansion tank.

It was missing the thermostat, so I flushed it and installed a Stant # 13356 160Ëš thermostat. It has a 7lb cap, so I've been hunting for a long neck 13lb with no luck. I was going to order one of the caps from a roadster parts retailer, but realized it's actually probably for the expansion tank?

Stant vintage guide says 7lb for 68, and 13lb for 69.. it also says 180 degree thermostat stock, and 195 is the optional temp..

Did someone add a cap neck onto a late style radiator? Tough to find a photo of an original setup... but this could be a real cob job install mix-n-match too.

Can anyone identify what components are put together and do I need to run the expansion tank? Is the expansion tank only used with the 13lb cap?

Photo below.. thanks for any guidance.. trying to keep it cool!

Welcome
I thought most all roadsters had the expansion tank though I am not sure on 1500's, so I would run that if available. The radiator appears to be from a 2000. Also there is a GM one-wire Alternator conversion (not that has anything to do with your cooling issue). You can verify motor by the serial number on the block between cylinder 1 and 2. It looks like a 1699 and if so, the S/N will start with an "R". The thermostat tower and neck look correct for a 1600, but because of this the hose, and the 2000 radiator appear mismatched,

You are missing the fan shroud. It is very important for proper cooling. Also check and see if the lower scoop is still in place. It is at the bottom of the radiator behind the bumper. These often get damaged and removed. On my 69 2000 the pressure relief cap is on the overflow tank and a non vented cap is on the radiator. A viable alternative, and many have done it, is to convert to an electric fan, although the bottom scoop is still a good idea.

I don't believe that is even a roadster radiator.
It looks far too wide, and seems to be too close to the engine/away from the mounting points.
The small kink in the hose will also not help with the flow for cooling.

Hard to tell from the picture, but the original 'bars' accross the front area to mount the original radiator don't look right.....

All that being said, a radiator is a radiator, and it possibly could be made to work.
I don't remember seeing a car without an overflow tank, if you haven't got one, it's a good idea.

The scoop below the rad, mentioned previously, bolts to the bottom of the roadster radiator, so you likely don't have it.

Overheating can also be caused by ignition timing or fuel issues. After solving your radiator issues, I would suggest you investigate the distributor to make sure it is working properly, then the carbs.

I was just mentioning the radiator width and hose kink but Daryl beat me to it...lol

Thanks all for the replies.. Could be completely wrong.. and the hose appears a little more kinked than it is, I saw that but after messing with it a little it 'seemed' ok. I would like to procure a fan shroud, and I didn't know about the scoop. I don't recall seeing anything scoop-like under it so guessing it's not there, but I'll go look after work tonight. I timed it the other day and I think the condenser went right after because it's running like garbage now. Has 4 new NGKs. I think it needs a valve adjustment too, it's noisy..

Does anyone have an opinion on the 13lb cap vs 7lb?

It looks like a 65 radiator, which is unique to that year.
1500s did not have expansion tanks, but some people have added them.
1500s did not have the air scoop.
You will probably have a hard time finding a 65 fan shroud.

I will fix the radiator hose for full flow*

Will a 65 radiator work on a 1600? does the 1600 have more rows or something?

steve_car wrote: Wed Jul 29, 2020 2:39 pm It looks like a 65 radiator, which is unique to that year.
1500s did not have expansion tanks, but some people have added them.
1500s did not have the air scoop.
You will probably have a hard time finding a 65 fan shroud.

Post some pictures of your car for reference so everyone can see your beautiful car and correct 65 1500.

I would advise fitting an expansion tank to improve the cooling system.
You can keep the setup you have, appearing to be stock '65 and install a stealth expansion tank on the engine cross member way out of sight.
Route the overflow hose to the new tank, fit a 7lb cap to the tank and a blanking cap to the radiator.
I have done this to my '65 and the cooling system is far more reliable in our summers than the original burp out non-return system.

Here is a picture of my radiator:

Nothing like an expert, or someone with the perfect exemplar to set things straight in a hurry!

notoptoy wrote: Wed Jul 29, 2020 9:48 pm Nothing like an expert, or someone with the perfect exemplar to set things straight in a hurry!

Ya, you should see this car.