Ok guys I just punched a 400 RAIII 30 over got BeCool rad, 160 tstat,new fact water pump and divider plates,(for 1970 engine), 7 blade clutch fan and shroud, TH400 w/2500 stall speed conv.,297 gear, edlbrock 750 carter (slightly richened from stock settings/dont have gas analyzer to check) sitting in 67 LeMans. Problem: still idles hot to 215 after about 20 mins. Ok at road speed speed. 12 degrees initial timing 36 total in at 2000 rpm. what else can I do? Thinking about installing maxi-cool oil/trans cooler to help.Allthough it seems like this setup should run cooler as it is.Help!!!!!!!!

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gtvoll@neo.lrun.com

Ok guys I just punched a 400 RAIII 30 over got BeCool rad, 160 tstat,new fact water pump and divider plates,(for 1970 engine), 7 blade clutch fan and shroud, TH400 w/2500 stall speed conv.,297 gear, edlbrock 750 carter (slightly richened from stock settings/dont have gas analyzer to check) sitting in 67 LeMans. Problem: still idles hot to 215 after about 20 mins. Ok at road speed speed. 12 degrees initial timing 36 total in at 2000 rpm. what else can I do? Thinking about installing maxi-cool oil/trans cooler to help.Allthough it seems like this setup should run cooler as it is.Help!!!!!!!!

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gtvoll@neo.lrun.com

Is the fan clutch new?

Yes fan clutch is new. I also have two quarts of 40 degree below coolant additive in the system($24.00 a quart).

My car crept up slowly also with almost the same mods done as yours, well it ended up being the air fuel screws on the carb I had them a hair to lean. On the Holley I turned them out 1/16-1/8 on all 4 and it made the car go from 215 on the freeway to 195, so that does have something to do with cruise and idle, I haven't got to take it out in traffic yet since the change but that way home the temp stayed rock solid with nothing else done. My car is apart until this Sat., so I will post how it does in the 105 degree heat in traffic, hopefully it is ok.

Get rid of that 160 t-stat and put in a 180. The 160 t-stat is not allowing the anti-freeze water mix stay in the rad long enough to cool down. Trust me I have similiar set-up with same problem. I switched to 180 t-stat and my car runs 180-190. Also you may want to try more water versus anti-freeze in the mix. But don't get carried away if you live in an area that experiences cold weather.

How was the block prepped and cleaned? A small amount of scaling will cause cooling (heat transfer) problems.

My dad and I acid wash all water passages and you would be amazed at the amount of scaling that we get out (even after the block has been hot tanked).

With the engine assembled, you do not have this luxury. Make certain that you flush your system real good.

I like to run water, a little anti-freeze and Red Line Waterwetter.

Good Luck

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Dave "Big Injun" Anderson
www.PontiacDragDays.com
www.PontiacEnthusiast.com


[This message has been edited by Big Injun (edited 07-19-2000).]

Greg,
I am trying to understand any kind of normal driving that requires an engine to idle for 15 to 20 minutes. The modern cars have spoiled us all as they have elaborate computer controlled cooling fans to cool much smaller engines, and most will idle without the temp climbing. However, our original Pontiacs never had that capability. I have bought and driven numerous new V8 Pontiacs over the years and all would eventually reach too high a temperature if left idling. The fact that your engine cools down to normal temperature in normal driving indicates no problems with the system. If you want better cooling at idle, try installing an additional electric cooling fan that can be switched on at will. I don't recommend to try to run one exclusively as most can not move enough air to do the job in all around normal driving. Along with an electric fan, it may be necessary to speed up the idle rpm slightly in order to turn the water pump a bit faster at idle. Jim Hand

Even with a new fan clutch you may not be moving enough air through you radiator to disapate the heat. I can suggest something that will cost less than $20.00 and may solve your problem, it worked for me. Remove you stock fan and clutch and replace it with a plastic Flex-a-lite fan, they can be bought for about $15.00, you will also need a spacer. I am not shure the exact size of the spacer but off the top of my head I think it is a 2 inch. I had a stock type fan and clutch on my car and no way did it pull as much air through the radiator as the plastic fan with a spacer.

Ok guys I installed a robert shaw 180 deg tstat and ran her down the highway at 75mph air temp that evening was 69 degrees. It ran at 195 do you think that that is acceptable? I also noticed that the manual calls for a 190 deg tstat.

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gtvoll@neo.lrun.com

The old poncho v8's need to operate in the 180-200 range. That's normal for them. If you don't run them that hot,you are actually losing power. How long did it take for your car to get to 195 at that speed? It sounds like your on the money now. If you want additional cooling run a 60/40 water to anti-freeze mix. More water makes engine run cooler. But if you put too much water you have to contend with accelerated rust. Make sure your fan clutch is working properly. I personally don't like flex fans cause they drag on the engine at all rpm and take a permanent shape after time and renders them ineffective. You may also want to try some thick weatherstripping foam,found at local auto parts,seal off any gaps in the shroud to rad area. You want the fan pulling air from within the shroud. BTW how does it do at idle now? Also in my previous post I forgot to tell you to burp the system. Any trapped air in the cooling system will make the engine run cooler. If you must run a cooler,the only one I HIGHLY recommend is a tranny cooler. The transmission put a tremendous strain on the cooling system.

Sorry trapped air will make your engine run hot. Typo above.

It seems sometimes that this cooling thing is a mystery. Why some cars cool fine and others have problems with the same stuff? I am not sure if thin cylinder walls could be a factor or not? My .060 over 455 cooled fine in the Arizona desert in the summer when I drove it on the street. I do have a Desert Cooler radiator and a good quality stack plate trans oil cooer on it that is positioned to get direct air flow. Also I have a buddy that had cooling problems and when he installed a Robert Shaw thermostst his problem went away. He used a 160 degree but a 180 might work better if the water needs to be slowed down a bit.

Also ther are different size pulleys that go on the water pump to control water pump speed, this could also be an area to experiment with.

Tim Corcoran

Ok guys I installed a PermaCool remote transmission oil cooler with 500cfm fan.I tucked it over on the passenger side of the radiator core support and then made an opening in the support so air can come through.I ran at idle in gear for 45 mins and never got over 197 deg (I'll take that!).
Now for the next question: What would you say is normal operating temp for a TH400?
I have some reservations about not using the oil cooler in the radiator. I will be installing a trans temp gauge today then, extensive road test.

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gtvoll@neo.lrun.com

Ok, Results of remote trans cooler are great! Idled car for 45mins in drive water temp never exceeded 197deg trans temp stayed at 180deg. Took car out and flogged it around town then out on highway water temp never got over 200 trans never got over 210.
I am satified with these results. Thanks to everyone for the help.

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gtvoll@neo.lrun.com

I think we have learned something here to make a mental note of. My 65 leMans with a .060 455, loose converter 3.73's, 255/263 .597/.603 cam always cooled exceptionally well, even in the Phoenix 100+ weather with a Desert Cooler radiator. I never thought that the trans cooler may have been a contributing factor. I have a high capacity stack plate trans cooler that cools the trans independant of the radiator. I guess the trans can over tax the cooling system. Something to consider.

Tim Corcoran

OK, I'm jumping in late on this discussion, but I'm a bit confused about something Al mentioned above. How does installing a lower temp. tstat slow down the circulation of the coolant? And in every industrial-type application I ever saw, the fix to an overheating problem was to increase the circulation rate, not decrease it. It seems to me that if the engine is running at 195 degrees, either a 160 or a 180 tstat will be wide open, allowing full flow, trying to get the temp back down to setpoint. I don't know whether or not a 160 tstat has a greater "wide-open flow" than a 180, but I thought that a tstat controls temp by what point at which it opens, not necessarily by how much it flows when it is open.

Picture standing in the snow with no clothes on on a non-windy day. You're telling me that the faster the wind blows, the warmer you'll be because the air is moving too fast past you to pick up any of your body heat (ie, the coolant is moving too fast thru the radiator to give up it's heat)

And GregV, your original complaint was that the car would overheat if it sat and idled and that it was OK at speed, but your test of the tstat swap was to run down the highway at 75 mph on a cool eve. That's apples and oranges.

Sorry about jumping in so late, but I've just "discovered" this site.

Kirk

What Al is referring to is the lack of retricted flow thru the radiator. If the fluid passes thru the rad to quickly the "fluid" doesn't have time to cool. I personally feel this is not an issue unless you completely remove the t-stat.