I put a 195 degree t-stat in my bird the other day with a small hole drilled in it for bleeding air.

And it runs right around 190-195 as long as I'm moving but when I let it sit idleing about 5-10 min. the temp. gauge moves right on up to 220-230.
I don't think it stop there if I did'nt shut the car off or drive it to get some cool air across the rad.

Is this right ?

Actually, when I turn my car off - the engine temp rises - b/c there's no coolant flowing through at all - but then with time, the engine will cool down - opening the hood helps with this. But this isn't your question...

I think electric fans could maybe help that, but really, if no air is flowing across the radiator, it can only work so well. Fans only do so much, but they certainly do their purpose.

There are other tricks to keeping the temps down, I just don't know any offhand!

I still say that when your motor is over 200 deg, both the 160 and the 195 thermostat are wide open and therefore the type of thermostat will have no effect on engine cooling. I would avoid the 160 because on cooler days your motor will run too cool. They were designed to run at over 195.

I was wondering what a phalangalevalve was. I was going to check e-bay to see if there were any for sale.

I've got one I'll sell you, but they're pretty high. While your at it it's a good idea to replace the muffler bearings as well.

My own phalangalevalve has some issues, but you can't find how to tune the darn thing in the 1968 manual.

The '69 manual briefly mentions something about maintaining its longivity with vasaline lubrication and a protective rigid rubber shroud if driving in continous wet weather.

Should work for a '68 as well, I guess.

Yes but, you need a metric screwdriver to tune/adjust properly.(also works well on muffler bearing).

Greg is also needs to be left-handed.
If that doesn’t work though you can always use a metric cresset wrench.

Well is I remember right and I think I do.

It was Quenton who told me to run a 190 or 195 degree t-stat

And about the hole I also believe I read that soemwhere on this site awile ago.

Again it only overheats when I leave it idling for awile without the car moving.

Yes I do believe I have the right fan shroud, 5 blade fan, x panels and such.

i've seen thermostats engineered with a hole and a brass 1-way type valve in it. it's supposed to help purge air when filling a dry system, i think.... or maybe it's to get the heater working faster. i think it measures about .030". not sure of any help or hinderence on the Pontiac8 though. i pretty much see it only on foreign 4s i think.
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it sounds like probably an airflow problem if it cools down when you get going. can you feel it pulling air?

Scott,

You are correct about the imports having them. When I was in college I worked at a Toyota dealership in the parts department and the thermostats had a small hole and one way valve.

Tom

I've seen a post or two here about the infamous hole in the thermostat, so Doug isn't on drugs or anything. Banshee is just a killer mean man, a rogue cop, a man without conscience, the Barretta of Detroit, etc, etc.

Actually, I think he was just kidding with you Doug.

A 160 doesn't work here in Tennessee, too hot during the Summer. I'm using a 180 and it seems to cover all seasons, Doug. Like you, if I get stuck in a traffic jam that temp goes up, and up and up!

The 18-inch electric fan kicks in at 210 and saves me, but it really only gets to that point on very hot (90 degrees or higher) days.

Although I never overheated (except for one stuck thermostat) in the 36 years I've owned mine, I now recall that a few times when stuck in long traffic jams in 90+ weather, I shut off the AC and turn on the heater to add another radiator to the system. Don't know if it was necessary but it was just an ounce of prevention. People pay a lot for a dry sauna.

I guess that having just an idiot light kept my paranoia about temp in check. It must not ever been too much for the engine since it's never been worked on in 37 years and 178,000 miles.

It's the other way around for me. At the Dream Cruise last year, temps were mid to upper 90s and after extended idling in gear in standstill traffic, the temp light would flicker a little. As soon as I was able to move, even a little, or shifted to neutral, the light would go off. After a few hours of this type of abuse, the light stayed on a little longer and I pulled into a lot to check it out. IR thermometer showed upper tank temps at 210 and there was no coolant odor or boilover, so I just hit the trigger point of the coolant sensor.

I have used the heat-on, windows open method after breaking a fan belt and having to make it just a little farther to stop in a safe location. I'm sure it doesn't hurt, but it is nowhere near as efficient as a 19", 7 blade clutch fan.

i think i read that the TVS wont kick in the vacuum advance until 230*, and the light comes on around 250*. That would give you a little warning before boil-over. i'd like to think the normal running temp would be lower... closer to 190-210* that's where my 6 runs.

Have the radiator boiled out. Sounds like you might have some clogged passages. Also check the temperature at the radiator. I did this and found my gauge was fifteen degrees F off on the high side. I expected a difference from the temp sender and the fill neck, but not fifteen degrees F.

Tom

This overheating problem seems to be a common thing shared between most firstgen bird owners (at least us w 400 engines). Mine is totally stock, with newly rebuilt radiator, all baffle pans, shrouds, x-pans etc in place, timing advanced accourding to the factory specifications an a vanilla (066) cam. Still, after sitting for 35-40 minutes in a traffic jam this weekend, the temp gauge slowly but steadily crept towards the top, just passing the marking below the 250F (having rally gauges) when I got out of it. Since I refuse to believe that there were no traffic jams in the late sixties, there must be something different with the engine compared to what came out of the factory late 68.

One item that might cause the problem would be that the coolant flow through the system is insufficient at low rpms. Has anyone here tried using a hi-performance water pump with improved cooling at idle as a result?

Snow, check this out if you haven't already:
water pump mod

Thanks for posting that link. I wish I had checked that clearance when I had to replace my water pump last year. Another winter project on the board. :-})

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif"> Since I refuse to believe that there were no traffic jams in the late sixties, there must be something different </font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">some will tell you "global warming"...lol

but no, I think its either missing baffles, the replaced water pumps, clogged radiators or gauges that misread...

It's the expensive gas.

Think back...I can recall seeing cars off on the side of the road ALL the time, with the hood up and steam coming from the radiator.

I believe a lot of it is as Bjorn mentions, non-stock/missing stuff in the cars and smaller/clogged water passages. I know I ran better in the 60's before my arteries started getting clogged.

But, back in the 60's there were many less stop lights, stop signs, traffic jams and slow traffic. When I first started working (1969) I got to work 20 miles away in 25 minutes. When I drive to that same area today it takes about an hour.

I think it's an alien conspiracy.

A thing that I noticed while scavenging for the right pulley for my new water pump is that from late 69 the pump was somehat longer (1/2") which puts the fan closer to the radiator. Also, the pulleys from 70 and up are of a smaller diameter (improved fan rpm). In theory this would mean both better air and water flow.

When you create horsepower you also create heat. If your engine creates twice the horsepower than it did when stock you need a "better than stock" coolant system.
Jim

The temp gauge is a auto meter which I bought last year.

My car runs 185-190 when I'm driving it but when I sit and let it idle it runs up to around 220-230.

I'm just concerned about it really overheating especially if I go to woodward this weekend where I know I'll be doing alot of sitting in traffic.
After you mentioned using a 160 t-stat I thought about it and it might be the right thing to do because it would take alot longer to reach 210-220 and so forth.

Does it help if you put it in neutral and bring up the revs a bit, to help circulate the coolant? Also , will running your heater/fan wide open help draw heat away from the engine? I know that works with more modern cars. Cranking up the heat when it's 90+ degrees outside is nearly unbearable, but I've done it before!

Has anyone ever heard of creating a bypass of the heater by using a "T" and both rear water outlets on the heads. I'm probably not being clear...but I am experiencing 220+ heating problems and have done everything mentioned in these posts including replacing the head gaskets in case they were blocking flow. I only have 4,400 miles on a newly rebuilt 69 400 block and 72 4X heads. I have got the highest flow water pump from Summit, High flow thermo, 11" pusher fan, 7 blade fan with thermo clutch and shroud, desert cooler radiator, upper and lower baffles, .025" clearance on my divider plate, and ALL parts are brand new. I can go about 15 miles at low speeds (40 and under) before 220 and about 5 miles at 70+mph. I hate to belabor this subject BUT this can't be what was designed in 1968! HELP!!!

I think the a/c radiator that sits in front of my four core engine radiator hurts air flow. Also having the tranny oil running into the radiator hurts cooling.. A friend of mine says that putting a automatic in nuetral causes much less heat. This could be helpful in heavy "standing" traffic. I've got a new radiator, fan clutch thermostat and aluminum intake, she still runs hot.