[Formulajones]

It's not that it's too hot, it's just more than I prefer to see for a few reasons.

One, you have very little cushion at all if you come to a stop in traffic or sit and idle for a while. If it starts creeping even higher, then what. This isn't something that you should have to worry about when driving the car all the time, so make sure you get it under control now.

Two, todays fuel hates those kind of temps and if you plan to run pump gas in the thing all the time, you may find yourself in hot fuel related situations. Everything under the hood gets pretty hot, and the higher those engines temps the worse that gets. Especially when running a carb and only 6-7 lbs. of fuel pressure.

Wasn't a big deal back when the cars were new, we had better fuel then. Todays cars are EFI with 40-60 PSI of fuel pressure so really hot temps doesn't affect them.

I see this all the time in Arizona. Bunch of high dollar cars can't even get out of a Goodguys event idling through the West World grounds without puking antifreeze all over the place, they gotta pull outta line and shut it down. And that's when ambient temps are only in the 80's. I have no idea how they even handle Phoenix traffic, I guess they just don't drive them.
People think they are fine because it's only running 190 when it's moving down the road. Soon as they put the car in a real world situation though, they are in trouble fast. If everything is right, these old cars can run all day in all kinds of situations and not overheat.

[70GS455]

Originally Posted by Bruce Meyer

195 too hot? I don't think so. Especially with the A/C on. He is fine. Did you know that some of the 70,s Pontiacs came with a 195 thermostat?

Yes, and they ran within a few degrees of 195, prob 200 or so. If someone installs a 160 or 180 t-stat, water should run within a few degrees of that

[Schurkey]

1. The anti-freeze concentration is not the problem here. I've run 70--80 percent antifreeze. I still like it strong.

2. The engine is not in danger at light throttle until the coolant temp is WAY hotter than 205F. The "HOT" light on the dash didn't come on until 240--260 degrees. At heavy throttle, detonation might set in leading to piston/ring/combustion chamber problems, but not at idle or cruise.

3. Unless this thing has electric fans, running 20 degrees above the thermostat rating at idle or cruise indicates a cooling system and/or engine operational issues. If I had a 180 thermostat and the engine ran 195+ at idle, I'd be looking for a cause. There's about two dozen possibilities and listing them all is getting old.

[grivera]

Originally Posted by Schurkey

1.
3. Unless this thing has electric fans, running 20 degrees above the thermostat rating at idle or cruise indicates a cooling system and/or engine operational issues. If I had a 180 thermostat and the engine ran 195+ at idle, I'd be looking for a cause. There's about two dozen possibilities and listing them all is getting old.

http://forums.maxperformanceinc.com/...89&postcount=7

Is this the expectation for a thermostat that is fully open at rated temperature? I ask cause the chart in link above says a 180 stat starts to open from 177-183 and will not be fully open till 202 degrees

[Formulajones]

I tend to agree with Shurkey and I eluded to that scenario in previous posts. When you're running 25 degrees above the rated thermostat temp, that's an indication the cooling system is running away, and at any point from there forward you get stuck in traffic, you're likely going to see that temp climb and you'll start squirming in your seat.

Speaking about thermostats, typically my stuff runs at the rated thermostat temps. Technically they aren't even fully open to do so.

For example, I run 160 in most of the stuff here. My 454 Chevelle when ambient temps are 95 degrees or less, it will cruise at about 162-163 on the highway, and actually cools down on backroads that are 35 mph, to about 158-159. When it's 100+ outside highway temps might see 170-173, and again cools down a touch on slow driving backroads. I suspect the thermostat probably isn't fully open until I see those 100 degree temps outside.
Dad's GTO will almost mimic my temps exactly and he has 100 cubes and over 100hp on me.

It's easy to see what the cooling system is capable of with a colder 160 stat.
Seeing as how they both run in the 170's on the really hot days, they are below a 180 stat. If I were to install a 180 stat in either car, you would see the temps pretty much hold rock solid right around the thermstat rating because we know the system is capable of cooling even more based on how it performs with a 160 stat.

In the OP's case, his temps are already starting to run away with a 180 stat. Putting in a 160 stat won't do anything for him. It'll still run 205 with the only difference the stat is opening sooner, but the cooling system still doesn't quite have things under control. The engine temps should honestly be closer to the thermostat rating if all the systems in place are doing their jobs.

I would suspect with such a mild engine build there are probably areas that could be looked at and improved upon to help the cooling system. I'd say 80% of what I've worked on over the years it's usually something with the engine, and that's usually tuning. Very few times have I seen stock cooling systems that aren't capable of cooling an engine.

[Bruce Meyer]

Originally Posted by 70GS455

Yes, and they ran within a few degrees of 195, prob 200 or so. If someone installs a 160 or 180 t-stat, water should run within a few degrees of that

You can install a 160 thermostat and drive around in Phoenix Az in the middle of July with the A/C on and I will bet good money that it will run a lot hotter than a few degrees over 160.

[70GS455]

Originally Posted by Bruce Meyer

You can install a 160 thermostat and drive around in Phoenix Az in the middle of July with the A/C on and I will bet good money that it will run a lot hotter than a few degrees over 160.

With a large enough radiator, or one that is super efficient and has an overabundance of cooling capacity, I beg to differ.

Sent from my SM-S901U using Tapatalk

[Formulajones]

Yep, It just depends on how good the cooling system is.


I've seen some with 160 stats that run closer to 200 degrees on a 75 degree day. That's a problem. No way it would survive summer temps at all. It either has a cooling system deficiency or something out of whack with the engine.

[Bruce Meyer]

Originally Posted by 70GS455

With a large enough radiator, or one that is super efficient and has an overabundance of cooling capacity, I beg to differ.

Sent from my SM-S901U using Tapatalk

Um yeah. OK. If you want to cut up your car to fit a radiator out of a semi.

[70GS455]

Originally Posted by Bruce Meyer

Um yeah. OK. If you want to cut up your car to fit a radiator out of a semi.

I'm just saying there probably is a radiator that should keep temps under control on a hot day in Phoenix with the AC on. I don't live there so I don't know exactly which one

Sent from my SM-S901U using Tapatalk

[MatthewKlein]

Originally Posted by 64speed

When I filled my radiator up on initial startup I put two gallons of concentrated antifreeze in and about a gallon and a half or so of distilled water. Not an exact measurement but it has a good bit more antifreeze in it than distilled water. My car has a 180 thermostat and it’s running between 195 and 205 at idle and settling down to 195 or so around cruise. I know this is more than acceptable especially in 100 degree South Carolina but I just wondered if it’s the ratio or the thermostat that might be contributing to this. I have a know good 180 I may swap in next year or if this one creeps up. Just don’t want a stuck thermostat to mess me up. Things are running too good.

You can put the thermostat and a thermometer in a pot of water on the stove and test its operation. Then you know for sure. I've had rare occasions where it took 3 thermostats to get one that opened where it was supposed to.

Regarding coolant - Modern antifreeze is so good now there is no reason to run the old green. Global coolant should last a lifetime in a classic car with less corrosion.

[64speed]

I’m pretty sure now that it’s the thermostat opening off temp or slowly. It holds at 195-200 here steady at idle with AC on full blast. It’s been I’m the 90s here with several high 90 degree days and it seems to hang around there so far.

[Schurkey]

Originally Posted by 64speed

I’m pretty sure now that it’s the thermostat opening off temp or slowly.

Put a (TESTED) thermostat in it, and know for certain.

I've seen so many deficient cooling systems and/or engines running with faulty tunes causing overheating that I have no faith in anything until it's been tested and validated.

[Schurkey]

Originally Posted by grivera

http://forums.maxperformanceinc.com/...89&postcount=7

Is this the expectation for a thermostat that is fully open at rated temperature? I ask cause the chart in link above says a 180 stat starts to open from 177-183 and will not be fully open till 202 degrees

The point is that at idle or cruise, the engine is loafing, the cooling system should also be loafing along. If the thermostat is WFO at idle or cruise, it's got no reserve capacity for when you're having fun.

Which is why at idle or cruise, the engine temp should be near the thermostat rating. Then when you hammer it, the temp can increase 10--15 degrees and the thermostat still has control of the temperature. You REALLY hammer it, the temp goes above what the thermostat can manage, and then the cooling system is WFO but (hopefully) not so hot as to promote detonation, damage the engine, etc.

But if you start off at idle or cruise at ~20 degrees over the thermostat rating, the thermostat is WFO already, you hammer it and you're totally screwed. The best you can hope for in that situation is that the tune gets more appropriate as the throttle opens.

It's a massively interconnected system--engine tune, cooling system capacity, vehicle dynamics--aerodynamics (including aerodynamics through the condenser, various fluid coolers, radiator and under the car), weight, gearing, rotating inertia, and all the rest.

It ain't right...until EVERYTHING is right.

[JSchmitz]

What kind of thermostat are you running? High flow or standard?

[Cliff R]

Just curious, what are the engine specs and details?.....

[MIke L]

I was gonna start a thread on this but maybe this would be a good spot…..
Are all antifreeze products the same?

Is one better than another in lowering and maintaining temperature, or does the 50/50 premix of any given brand really doesn’t matter that much?



Thanks

Mike

[Formulajones]

That's a really broad question. Antifreezes aren't the same and differ quite a bit from one to the next.

One of the more popular antifreeze brands among classic car owners is Evans waterless coolant. It's a little more pricey but it's a one time purchase, unless you spring a leak or need to change a pump or radiator. You don't have to worry about corrosion with this stuff.

As far as one or the other making a difference in cooling temps, I've never experienced that myself. My cars run the temps they run no matter what I put in or how strong it's mixed.

[HWYSTR455]

There's not enough ignition advance at idle, or driving.

What's your initial timing?

What's your timing at idle?

What's your total timing?

What's your timing at cruise RPM?

This is the distributor with no vacuum advance?

What kind of fan do you have, and is there a shroud?

No one has asked the basic questions yet.



.

[Formulajones]

Yeah I eluded to the tune early on in his other thread, specifically timing, but he's assured us he feels it's good.

Me personally, I agree, more idle timing would help the situation and a correctly dialed in vacuum advance is always a plus. I've said before 9 times out of 10 the cars that I have my hands on, timing is usually the problem that cures lots of things like different drivability issues, carb issues, as well as temps.