72CUTTY

i have a 72 cutlass i have read a couple threads about themostats ( 180 and 160). Im about to change the thermostat on my car it started running a little hot. this is my every day driver.. should i go 160 or 180? i will also flush the radiator, fill it with 50/50 coolant and replace the radiator cap.

This is my car.. the rims are temporary!

jaunty75

What thermostat is in it now?

Also, if your car has been running ok and now it's all of sudden running hot, wouldn't it better to find out why and fix that?

Lady72nRob71

180* Mr Gasket high flow t-stat.

Make sure your fan clutch is working - lots of air should be moving when hot at idle.

72CUTTY

Dont really know how to test the fan clutch.. i was going to replace the cheaper parts first then take it from there.

oldcutlass

X2 to trying to figure out why its running hot. As for the thermostat question, the 180 deg is what belongs in there, if you put the 160 in you will not have much heat in the winter!

Make sure your radiator isn't clogged up the flush is a good place to start!!

Lady72nRob71

Should make some good air noise, too and your hair whippin' in the wind under the hood! If it just freewheels it is bad.

Does it run hot on the road or only at stops?

Fear Reborn

Being in cali u can definatlety run a 160. I have a 72 stock 350, 160*, flowcooler aluminum waterpump, and a heavy duty fan clutch from a 87 307. Car never got above 195 on our 90 + week we had. Even took a 250 mile round trip at 70 + during it.

72CUTTY

Well ... I installed the 160* mr gasket thermostat.. flushed the radiator , filled it with 50/50 antifreeze.. hope this keeps my car a bit cool.. this was my first time replacing a thermostat.. forgot to tested .. hopefully it opens.. i will see how it goes tomorrow.. i do have one question.. the mr gaske thermostat has like a little screw looking like pellet on the thermostat.. i was wondering if that needed to stay there or if needed to remove it?

Lady72nRob71

Nothing should be removed from new t-stats, just install the pointy side up and make sure it is centered in the hole before installing gasket and outlet.

yeahbuddy

How did that 160 t-stat work out for you? I am in CA as well and hit 210 in some bumper to bumper traffic last week when it was 100+ degrees out. I got a 195 t-stat in my 68 Cutlass with a 350...which is what was in there when I got the car. Seems a bit high to me. I have a 160 t-stat that came with a used Edelbrock intake I just bought. Thinking of using it when I get it installed. It runs at 190 average now and creeps up to 200-210 during traffic.

72CUTTY

i started having this engine noise.. im thinking its probably a lifter. Now my question is, Can i be doing that because the car runs cold? i stalled a 160 stat and now my car runs at about 160 when its warm ans goes up to 180 on stop and go traffic is that okay?

Qwik71442

160 when its warm and up to 180 in stop and go traffic is good and I would seriously doubt these temperatures are the cause of your noise

yeahbuddy

72Cutty I started getting engine tapping/chattering noise last week as well and it ended up being the bearing in the water pump. Swapped out the waterpump and it solved the issue. Got the pump from Napa for $90. Also, I run a 160 tstat with a 2 row 1" aluminum radiator and I keep around 180 when cruising and 190 on hotter days. Hasnt passed 190 since put the new rad/tstat in...used to climb to 210 before.

oldcutlass

All a thermostat does is set the minimum operating temp of the engine. It has nothing to do with the maximum. That is determined by other things, fan system, radiator, size, and water pump. Once the thermostat opens, its function is completed and plays no further part in engine cooling.

The problem with running a thermostat that is too cold in colder temps is the engine may not run efficiently, oil can be contaminated with moisture, fuel mileage may be poor due to poor fuel vaporization, lack of heat in the winter, etc...

In the summer when temps are higher, a 160 degree thermostat may give a few more minutes, with an engine that has overheating problems, to when it actually overheats. Other than that your engine will run at what ever temp it generates.

210 - 220 degrees in extreme traffic with a normal cooling system is not out of the ordinary on a very hot day.

Is your oil low, too thin of viscosity, poor oil pressure? Olds rockers are notorious for chattering with old age? You need to determine which one/'s are noisey. The other thing may be that you have some dirt in a lifter causing it not to pump up all the way. I've used rislone, marvel mystery oil, transmission fluid to clean up lifter noise.

72CUTTY

yeah i saw that lucky you!!! my noise is not that loud but its getting louder...it looks like its coming from under the valve cover.I took my car to my mechanic, he says sounds like its either a bad lifter or rocker arms need adjustment.. im suppose to take my care on sunday . hope is nothing big!

72CUTTY

Oil pressure is good.. i always used mobil oil, this time i used valvoline and my mechanic seems to think its either a bad lifter or rocker arm needs to he adjusted.
Hes gonna check the rocker arms first then go from there. I have scorpion rocker arms not olds stock. My engine was rebuilt about 3 years ago. I only use sae 30 or 40 oil. I was thinking maybe i should thow some oil cleaning product in there , then do a new oil change and filter before he opens up my valve covers. What you guys think? What " oil cleaning" fluid i should buy?

oldcutlass

If you have a set of adjustable rockers, one or more might have loosened, let your mechanic give them a quick inspection and adjust as needed.

Some of the additives I recommended will not hurt. Just change your oil after a few hundred miles.

72CUTTY

this is my daily driver. A few hundred miles oil change sounds expensive.. i was doing it every 3 months. ill start doing it every 2 months!

oldcutlass

Nooooo, lol, I meant a few hundred miles after you add the rislone, marvel mystery, or the trans fluid.

oldsguybry

hold it right there ! This may be the problem I have , what do you mean by freewheels , and are we talking about the fan on the end of the water pump ? The one on my car spins freely quite easily , and as you know I've been racking my brain trying to locate and fix the problem ... so could this be the problem noise I've been trying to diagnose ?

sorry for the hijack

Texascarnut

Freewheeling of a fan clutch means it is not engaging as indicated by low or no air volume being noticed even at idle speed. Fan is just barely turning. With the engine running and increasing the engine RPMs up to 13-1500 RPMs and you should be feeling quite turbulent air between the fan and the firewall.

Fan clutches are intended to engage the fan at no or low speeds. When engine rpms are sufficient to be propelling the car at 35-40 mph there is sufficient air flow across the radiator to reduce coolant temperature and the fan basically cuts out to reduce power consumption. If coolant temperature rises with the engine at operating temperature but at idle speed for a few minutes, such as being caught in a traffic jamb on a warm day, chances are the fan clutch is shot.

72CUTTY

How long should i leave the engine at idle after pouring 1 quart of atf before i change the oil?

Texascarnut

About 15 to 20 minutes at 1000 to 1200 rpm. If the problem still persists a simple quart of Rislone, ATF, or Marvel mystery oil isn't going to fix it.

How many miles does the engine in question have on it? When the rebuild was done did it get new lifters and push rods?

72CUTTY

the engine was rebuilt 2 -3 years ago.. new everything.. scorpion rocker arms, new push rods, new lifters.. ive been driving the car everyday now for the past 8 months

brown7373

I seem to remember reading somewhere in the 72 Olds Service Manual that normal operating temperature for a 72 is 200 degrees. I did find in the Service Manual that the Idiot light doesn't come on for overheating until 248 degrees. Sometimes I think we all get a little paranoid if we have a gauge and see the temperature go up a little bit.

The way to check for clutch functioning is to block most of the air to the radiator, start and idle at 2000 rpms. After 5 to 10 minutes, if the clutch is operating correctly, it will engage and there will be a noticable sound of rushing air. Remove the blockage and reduce the idle to 1500 and let the engine cool some before shutting down. Make sure it free wheels when it's cold and the engine is off. If you spin the fan it should go around some and stop. The manual says if it turns 5 times when cold, replace it. Or if it doesn't turn when cold, replace it.

72CUTTY

Im going to try that gunk engine flush today and change my oil and filter. Hopefully the noise goes away if not ill be removing the valve covers this sunday to check!