Thermostat rating

[JollyGQ]

So Ive been digging for 2 days looking for a part number for a safety thermostat for my 70 1600. The manuals I have all say it should have a 160 but the part numbers in the tech wiki are for 180. So, digging more I found a reference to a thermostat that cross-referenced to a safety thermostat at Autozone, Failsafe Thermostat 7241-160.

So, my questions are:
1) is 160 the correct thermostat for my car?
2) has anyone else used the thermostat i found?

I see a lot of references to motorad/stant but they are all 180 and I can't find any alternate temp part numbers that cross from those.

Thanks in advance!

[redroadster]

160 is a summer thermo ....older less idea cooling system s cars can use to keep from overheating
But the thermostat controls minimum temp not maximum temp
So 180 is recommended
Yes a 180 starts to open around that

You need to heat the engine quick to the recommended temp as cast iron wears / scratches easily cold / roomtemp , but you practily cannot scratch it hot ..he heat riser exhaust valves came helped with emissions and wear

[JollyGQ]

Ahh, okay. I was getting confused because manual said its supposed to open at 160 so I thought I might be missing something. Thanks!

[DAC21]

Went with 180 myself for when the time comes (Inland So Cal) but I will be going with a re-cored 3 row Radiator as well. There was a thread on Facebook a while back about "burping" the cooling system after doing work. Apparently it can be a PITA. Mike Young recommended drilling a small hole in the Thermostat to help with that. I don't have details beyond that like hole size etc. Others have mentioned jacking up the rear end. Maybe someone else can chime in?

[david premo]

Alright I will do my best to explain this. The thermostat has nothing to do with how well the cooling system works! As long as the cooling system can exchange heat and keep the engine from overheating, then all is good. The engine should run at a water temperature between 180 and 210 easily, and on the high side 220. On a long cruise I don’t mind seeing 195 to 205 in the summer. Compleat combustion is a very important item for the longevity of your engine. What happens when we put in lower temperature thermostats we are the engine under lesser demanding weather runs too cold. In high temperature situations it’s the ability of the cooling system to dissipate heat that keeps the engine from overheating NOT the thermostat. I went to the trouble of looking up the factory thermostat rating and it calls for a 176 F or 80 C thermostat. Basically a 180 F is what they was they intended. Otherwise you tend to not burn all the fuel completely and in-burned hydrocarbons clog what is called the ring lands, the grove the piston ring rides in. After continued exposure to this rich condition from either too much fuel or too low of a running temperature the rings start to not move with the cylinder walls and the engine begins burning oil as it will bypass the oil control ring.
Now I know many people have gone to the trouble of up grading to aluminum radiators, but not all radiators are equal. What I mean by this is the Datsun Roadster 1600 and 2000 were designed with a “CL” type radiators. What that means is it has more tubes across than is standard, it’s a special type of core. Most radiator shops will put in a CL core and charge you accordingly, and they work great. Many of the aluminum radiators I see for sale are of poor performance when it comes to exchanging heat. They look like they are effective but I’m not sure that if put to the hard test how well they will preform. The other incredibly important part of the puzzle is having a cooling system pressure tester. The reason the engine can run this hot and not suffer has to do with the pressure applied to the coolant (water and coolant) in the radiator. By raising the pressure we raise substantially the boiling temperature of the coolant. So at an altitude of 5000 feet water will boil at about 202 F and at sea level it’s 212. So put a 13 PSI cap on the radiator and water now will boil at about 250 F, that is a massive difference. All of this said, the items you need to evaluate your cooling system are a temperature gun, a Stant cooling system pressure tester, and some patients as you evaluate what is going on. Sorry for making such a long post I think I’m going to stop for now.
Dave

[JollyGQ]

Went with 180 myself for when the time comes (Inland So Cal) but I will be going with a re-cored 3 row Radiator as well. There was a thread on Facebook a while back about "burping" the cooling system after doing work. Apparently it can be a PITA. Mike Young recommended drilling a small hole in the Thermostat to help with that. I don't have details beyond that like hole size etc. Others have mentioned jacking up the rear end. Maybe someone else can chime in?

I have a burping kit from Napa Auto. Very easy to use even though it doesn't have a cap that fits. I just use the black adaptor and gasket and it seals perfectly. Didnt have to jack it up or anything. Just put funnel in filler hole, put coolant in funnel and run engine and watch the magic happen.

Dave, thanks for the detailed info. Using my laser thermometer I'm at 201-208 at the tower, 210 at the front of the block where the temp sensor is and 184 at the top inlet of the radiator. So I guess it's where it should be.

Thanks everyone!

[Gregs672000]

Very nice explanation Dave! Understanding how things are supposed to work and the theory behind it helps a lot when trouble shooting.

[redroadster]

Went with 180 myself for when the time comes (Inland So Cal) but I will be going with a re-cored 3 row Radiator as well. There was a thread on Facebook a while back about "burping" the cooling system after doing work. Apparently it can be a PITA. Mike Young recommended drilling a small hole in the Thermostat to help with that. I don't have details beyond that like hole size etc. Others have mentioned jacking up the rear end. Maybe someone else can chime in?

Works in summer.... maybe , but you want to get to the 180 range quick to limit wear
Some themo stats (Mitsubishi ) have the toggle seal plug Tiny hole when full seals
I removed on my eclipse hoping for heat quicker in winter but it keeps the thermo from reaching temp almost 3-4 x as long

[Gregs672000]

Glad for this topic... I checked my old stat (happened to be out of the car) and I noted it looked open... in fact it was dead (I tested it). My spare is a 160, so I'll be off to Autozone in a bit... no wonder it ran so cold coming off the mountains a few weeks ago.