Kid Thunder

I have a 1967 330 2bbl Cutlass.
They list a 195* thermostat as stock. They list alternatives such as 169* 180* & so on.
195* seems really hot to me. the top hose is really hot to the touch.
I remember using a 180* in my 60s cars in the day.
Will that be ok for this car? Heat was good enough a 180* back then.

Don-M

joe_padavano

First, who is "they"?

Second, the top hose will be hot to the touch if it's 160, so I don't know what that point is.

The reality is that at 15-16 psi, the coolant will boil at about 250 deg F, so 195 is fine if you have a good radiator and cap. Newer cars use hotter t-stats for emissions reasons. If the car runs OK with 180, that's fine too.

MDchanic

What's your compression ratio?

Sometimes, if you are just barely making it without pinging on the highest available pump fuel, you can improve things slightly by going from a 195 to a 180, otherwise, 195 is fine.
Remember, higher temperatures correspond with slightly improved combustion efficiency (which is why they are used in newer cars).

160 seems awfully low to me - more like the temperature that a prewar car would like than a postwar car.

Oh, yeah, what Joe said, too.

- Eric

oldcutlass

I would use a 180 or 195, remember the thermostat is what regulates the minimum temp. The cooling system regulates maximum, so even with a 180 you'll find that your 330 will probably run some where between 180 and 200 depending on what the ambient temp is.

Kid Thunder

They is Rock Auto. The top hose just, seems to me, to be really hot. The rad is cool on the bottom so I guess everything is doing it's job.
I did replace the cap when I bought the car along with the upper, lower rad & the bypass hoses. Both belts with new coolant.
The hoses were so old that the lower hose with the spring was shrunk around the spring & felt almost gooey. Those hoses were there for a very long time.
Don-M

don71

Don, Just how much cooler is the bottom part of your radiator? In comparison....can you check it with a temp gun?

Don't want to be an alarmist, but what your post has described, makes me think the bottom of your radiator might be clogged. Thus not working efficiently.

If you get to having overheating issues, I'd look closely at that.

oldcutlass

Try and save the spring and insert it into the new hose.

Kid Thunder

Thanks guys that's what my son first said. Don't know if the temp lite works but it hasn't come on. the car seems is not over heating but it's not quite summer here yet, it will start to warm up this week. I don't have a temp gun but it is much cooler than the top.
Water seems to be flowing through the whole system but I will check it out.
Thanks

Octania

Don't know if the temp lite works but it hasn't come on.
============================
It should illuminate while cranking... well on models I am most familiar with.

You could ground the temp sensor wire (like the sensor would do in the event of overheating) and observe the light.

Kid Thunder

Ah, that's it. I thought so but my son said no this car is OLD technology!!! Punk.

Octania

The factory thought it prudent to prove out the HOT lamp each time the starter is activated, to ensure it is operable. If you watch for it.

m371961

I always used a low thermo. The high ones came in with the emission controls. I figured if I can keep the temp lower it gave extra time if the engine tended to heat in traffic.

MDchanic

1963 models used a 170 degree thermostat,
1964 and '65 models used a 180.

- Eric

brown7373

Of course the top hose is hotter than the bottom hose. The top hose lets the hot coolant, right out of the engine into the radiator to be cooled. After it goes through the radiator and is cooled, it goes through the bottom hose into the engine to start the cycle again. If the two hoses are the same temperature then your radiator isn't cooling.


The thermostat regulates at what temperature it lets the coolant flow. Once it opens, a 160 is no different than a 180 or a 195, and it is the capacity and efficiency of your cooling system that determines operating temperature. Otherwise, you could install a 30 degree thermostat and make ice cubes.

Octania

"the thermostat is what regulates the minimum temp. The cooling system regulates maximum"

Well, yes and no. The cooling system SHOULD be sized to dump as much heat as the engine sends it, and maintain the temp as designed by the thermostat. So, the upper limit is still the thermostat's job- if the radiator is so efficient that very cool water is entering the engine- think marine uses- then the thermostat will close down somewhat in order to maintain the coolant leaving the engine at your 180 or whatever chosen temp. Too hot and it opens for more cooling; too cold and it closes to let heat build more.

If, at open t'stat, your engine temp is still rising, then the radiator is failing to perform the required task [and/or hoses collapsing, etc.]

Kid Thunder

Thanks guys I learned a few things!!


Don-M

m371961

I was thinking of the 195 degree.
If you use a 195 that is the temp maintained as a minimum. If you use a lower one and the engine can cruise at 180, you get that extra 15 degrees if you get in traffic or under heavier load. JMHO, and we can agree to disagree. Granted, it may only give you a little time to get back to cruising, but I want that extra time.

MDchanic

I'm just pointing out that 180° is just about right for these engines; if GM had felt they would perform better with a 160° thermostat, they would have used one.

- Eric

oldcutlass

The problem with a 160 thermo is that in the dead of winter with freezing temps, you would not have any heat in the car.

jpc647

I've often contemplated if the 180* thermostat would be beneficial. Olds engines do run a bit on the hotter side, and the extra 15* might help. After an hour on the highway, there is definitely a difference in the car from heatsoak.

Not that the lower T-stat would fix it, but it certainly couldn't hurt. Mine, knock on wood, has never overheated, but it is an original style radiator, two core. I've had it boiled out, etc to be safe.

I've only driven the car about 20 miles this season because I bought a street bike and it's way more fun than the Cutlass, but if there a leak or a reason to dig into the cooling system, I'll be swapping it, just for curiosity.

Kid Thunder

I know it's been a long time since I posted this but I did change the rad & 180 stat & am happy with the results & get great heat now during the cold weather.
Maybe the rad replace just made feel better(All in my head)for about a $100 cost from Rock Auto.
Before this year I never knew Rock Auto was around(Bike guy here)but with their prices & variety I can often even buy small & pay ship & it's cheaper than going to a local store!

oldcutlass

Glad its working out. Yeah in most cases Rockauto is a great source, however some things I still like buying local.

jpc647

Which radiator did you buy? especially for $100.

Kid Thunder

From Rock. I think it was $109. I'll check when I get a second.

Kid Thunder

https://www.rockauto.com/catalog/raframecatalog.php?ck[year_1995]=true&ck[mkt_US]=true&ck[mkt_EU]=false&ck[mkt_CA]=false&ck[mkt_MX]=false&ck[viewcurrency]=USD&ck[ID]=0&ck[idlist]=0&ck[PHP_SESSION_ID]=1di5eafn7ruh8f0a2vkc0bcgu2

Kid Thunder

Doesn't work sorry. Just go on Rock Auto & check.

oldcutlass

Which one, it lists 3? I could not make a link work either.

Kid Thunder

SPECTRA PREMIUM / COOLING DEPOT CU161
So far so good. Direct install. Replaced the trans cooler lines from Inline Tube. They had it listed as for a Power Glide to Olds 330 engine. When I called them they were not much help. They said I must have changed the trans!! They had the Jetaway listed for other models but not the 67 Cutlass. Not a very good company to deal with.

jpc647

Thanks.

Post back after a few thousand miles, and let us know how it holds up. Mine has the original radiator in the car, it's still cooling okay, but I fear it's only a matter of time before it springs a leak.

Kid Thunder

Yes I felt the same way. I figured better safe than sorry. Also my hot light does not work. Have to get in the dash to change it I guess.
Been about 600 mile so far.

oldcutlass

I have this one on my car. Been on there since 2009 and works well. The only time the temp will creep up a bit is on a 100+ day idling in traffic, but recovers quickly. No shroud and a flex fan.
http://www.rockauto.com/catalog/more...nid=452&jpid=2

Have you tried to ground the wire on the temp sending unit with the key on to see if the lamp lights?

Kid Thunder

No but I will do. It works like the neutral light on a motorcycle. Thanks