[guccieng]

Originally Posted by gtome

Not to jack, but mine seems to run really cool? Havent varified temp with a IR gun, but I run 165-170. Is there such thing as too cool?

i think there is. you need to have your oil temp up to at least the boiling point of water (212 degrees F) to cook off the condensation that will form in the crankcase. if it builds up, you have created sludge and your sludge won't lubricate like oil. for example, my c5 vette (ls1) will normally run at 205 (coolant temp) with a oil temp of 240. i know my oil is hot enough to cook away the water. that 35 degree spread is only an example, and i don't know what yours is. if you run that cold with a similar spread in coolant vs. oil temp, you run the risk of sludge build-up. i run my cars (camaro and firebird) 180-200 degree range to be sure.

[GT182]

Originally Posted by 1971GTO

Didn't mean to ramble.

By all means John... do ramble. I think we all need the help with these cooling problems. Every bit of info helps us all.

[AGTO8U]

I run high compression (>10/1) and target less than 200 degrees (always) to help avoid detonation. Low compression (<9/1) 210 to 220 is ok, but cooler = better IMHO. I use cast impeller water pumps and bend the plate if necessary to achieve 1/16" clearance to the impeller.

[gtome]

Interesting! I will have to see what my oil temps are now.

[1967Tempest]

The license plate "MOD" made no difference. She ran 170* on the highway all day. Moved the license plate lower to see if it was "deflecting" air. Same 170* all day. I put 150 miles on her after the mod, so she wasn't sitting in the drive way idling.

[GT182]

Thanks for that 67Temp.... it's good to know.

I'll have mine out Saturday afternoon heading over to Fox Run's cruise night. I'll ride around a bit and see what happens too.

[Greg Reid]

There definitely IS such a thing as too cool for exactly the reasons gucci mentioned above....and I can quote chapter and verse from an old 1969 Automechanic's tech school text book to back it up...That's where I first read it.
Water and gasoline both wind up in the crankcase during driving...It'll only boil off and vaporize through the pcv valve at high temps.
I like my engines to run at least into the 180s to 220 range myself.

[BVR421]

I like 180 on anything I drive, my ideal would be to maintain 180 after warmup no matter if its Montana in Jan or Tucson in July
Difficult to achieve sometimes with our old Pontiacs and hats off to those who have that,
As far as 220 being too hot, for those who are lucky enough to have a late model car in the garage, have you ever actually checked the summertime coolant temp? Around here they run about 265 in the summer 205 in the winter. When people park their cars at work or the mall, you can walk down the line and at least half of the cars have their electric fans still running for 5-10 mins after being parked

[guccieng]

Originally Posted by BVR421

I like 180 on anything I drive, my ideal would be to maintain 180 after warmup no matter if its Montana in Jan or Tucson in July
Difficult to achieve sometimes with our old Pontiacs and hats off to those who have that,
As far as 220 being too hot, for those who are lucky enough to have a late model car in the garage, have you ever actually checked the summertime coolant temp? Around here they run about 265 in the summer 205 in the winter. When people park their cars at work or the mall, you can walk down the line and at least half of the cars have their electric fans still running for 5-10 mins after being parked

those high temps for emissions, not performance. our older cars are totally different animals. having a fan running with no water flow is absolutely useless. all it will give you is a cool radiator while your engine remains hot, and maybe a half-dead battery. my fans draw 18 amps each; how long would my battery last if they ran for 5-10 minutes?

[performerrpm]

iam in agree-anc with the poster who said check the water pump divider plate clearance. i didnt get as critticle checking mine when my bop water pump plates came and my pump was just a stamped impeller, but with a 16 inch volvo electric fan/shrouded and a desert cooler 4 row 160 thermostat my 11.51 cr 455 never went over 185 idling in 100+degrees and then all you had to do was speed the idle up and watch the gauge go down. and the fan with automatic thermostat usually ran more/longer once the motor was shut off.

i think the biggest thing to look at is the divider plates and a shroud, if you dont have one you should get one

[performerrpm]

180-190 in town and 170-175 down the highway is what i like mine to say

[GT182]

I've got no fan shroud or clutch fan, so those are the two things I need most of all after talking with Charles. I drove to our cruise night last Saturday and she did heat up on me..... but not so much that I had to worry about it. I flushed the system real good and took the radiator out to flush that by it's self afterwards. It's all back together but I haven't run her yet. Doing some touchup to the radiator support first. Got to get the grills back in and then give her a run.

So, the front plate "mod" is optional. It more than likely doesn't help, just as 67Temp said in his test. Tho I do like the bumper's looks better with the whole lower section open from lowering the front plate.

[66Mutt]

I did something years ago that led me to believe that shrouds were beneficial. I had painted the hood of my Corvette and went putting around town one day without the hood on. To my surprise the temp shot way up into the 240's. I would have assumed that the lack of a hood would have helped the cooling by letting more of the radiant heat out and not trapping that hot air under the hood. I still had my radiator shroud in place. But when I put my hood back on, the temps were 20 deg less. I figure a shroud would be analogous to a hood in helping direct the air. It may not be a valid conclusion, but it makes sense to me.
Doug

[kate`s67gto]

I swear that when i have my hand on the "A" pillar of my Olds i can feel the heat escaping from the engine compartment. There is a gap in the cowl lace at each end by "A" pillars and on the Olds the rear vents are functional.(on hood)

[1967Tempest]

Well, I agree that the bumper mod may not help. One caveat to that might be when temps get into the high 80's and 90's were a few more cfms might help. More to come on that. It is supposed to be in the 80's this weekend here in New Jersey, so I might have a better indication.

I have not made any changes since my last post and she still runs at 172. Should she run at thermostat??? For my next trick I will get a 180* thermostat and see if I can get her to run at t-stat on a 100* day in a parking lot at idle. More to come as the weather gets hotter.

Dave

[Greg Reid]

All you have to do is own a VW bug or Chevy Corvair to find out how important shrouding can be. One missing piece will absolutely fry an air cooled engine.
There's lots of info on this forum about the water pump divider. Seems there is some good evidence that it has an effect.
Also, I've read on these forums where some are saying that if any part of the upper hose is higher than the radiator, you can have cooling problems.

[dean7276]

Lots of good info.Thanks all for the responses.
Here's something else to ponder.
On my Trans Am (as with all) the temp gauge has 3 temps printed on the face.
far left is 100 deg. dead middle is 220 deg. and far right is 260 deg. there is no "red" warning markings anywhere on the gauge.One could assume that the exact middle of the gauge which reads 220 deg. would be a safe temp. Right? once it starts creeping further towards the right it should get your attention but dead middle seems safe? No?
Also, is there a way to find out at what temp. an idiot light would come on? That would then tell you what temp. the engineers feel is too hot.

[Greg Reid]

Originally Posted by dean7276

Lots of good info.Thanks all for the responses.
Here's something else to ponder.
On my Trans Am (as with all) the temp gauge has 3 temps printed on the face.
far left is 100 deg. dead middle is 220 deg. and far right is 260 deg. there is no "red" warning markings anywhere on the gauge.One could assume that the exact middle of the gauge which reads 220 deg. would be a safe temp. Right? once it starts creeping further towards the right it should get your attention but dead middle seems safe? No?
Also, is there a way to find out at what temp. an idiot light would come on? That would then tell you what temp. the engineers feel is too hot.

I would agree with that. I think 220 is OK...In fact, I like mine about there to cook any water condensation in the oil off...although some won't agree.
I think that light would probably come on in the 235 to 245 range...but just a guess on my part.

[1967Tempest]

Well today in Northern New Jersey it is pushing 90* outside. Mind you that it is still early in the year to add humidity. I took her out today and instead of her normal running at 170-172 she was running at 180*. I went for another 2 mile cruise and when I got her home she was idling at 196*.

Once I saw that I was thinking of making changes.

1st. I have a stock OEM replacement fuel pump from Napa. No matter what I do to richen her up, nothing happens after about 1.5 turns on the idle mixture screws. I look down and see gasoline trickling through the filter (Glass filter). I already have a Nice Holley 110gph mechanical pump in hand. Could she be starving for fuel??? I had noticed that the last time I changed the plugs they were dry fouled.

2nd. Running a 160* thermostat is fine, but once she gets to 196*, like today, the fluid will never have enough time to sit in the radiator. I looked at the stock replacement for a 1977 400 z-code thermostat and it is 192* Should I go to a 180* t-stat??

3rd. Bumper mod still makes no difference in CFM movement through the rad. If your baby is running a tad hot, it might not be worth drilling into the bumper.IMHO.

Thanks

Dave

[Peter Serio]

One thing I have done on several old Pontiac's of mine is to retro fit the cooling system over to what a car from the factory would have had if the car was ordered with AC. In the case of a 66-67 lemans or GTO you would need to get a AC core support, radiator, fan guard (shroud) multi-bladed fan or fan clutch PLUS those metal plates that mount to the bottom all the way across the core support. Those are often missing even on original factory air cars. They serve to transform the entire front bumper (the slot) into a vacuum for air. Making it nearly impossible for superheated air from the backside of the fan to recirculate forward and back into the radiator (being drawn down & underneath the car). These plates are like gold. I even made some for the lower edge of my '63 lemans following the drawing in the shop manual for an AC car.