[pontiacphil]

I've posted several times in the past about my 67' GTO overheating at idle. It ran hot before my total rebuild this past Winter and it continues to do so after the rebuild. It's a stock 400 bored .30 over, forged flat tops, true 9.48 compression, 670 heads w/ 3-angle valve job, stainless valves, roller tips, Crower #60242, 3:36 gears, rebuilt Turbo 400, Pertronix HEI, Quadrajet that appears to be set correct (not too lean or rich) factory intake, 2 & a half in. exhaust, Ram Air exhaust manifolds with X-pipe, running 91 octane gas, 7 degree advance at 750 RPM idle with total advance at 37 deg. at 3,000 Rpm, Flow Kooler water pump tweaked the way George advised me to, 180 degree Mr. Gasket themostat, Ames shroud. 400 miles on the rebuild running Mobil I 5w-30 with a can of GM EOS and 20 qts. of Mobil I ATF in the tranny.
Before, and after the rebuild, the car gets hot at idle. Will run in the 200 deg. range on the hwy. at 55 mph but as soon as you drop the idle down to under 1,000 RPM it goes to 225 to 230 very quickly. I shut it down at 230 but think it would keep getting hotter if I let it run. I set the idle up to 850 but it didn't help. Had my Harrison 4-core recored and it didn't help any. I ordered a Rodney Red 8 wks. ago and got it last wk. Jerry, the owner, was a very nice guy to work with. Got it installed this morning, used a 50/50 water to antifreeze ratio. used foam to seal the gap around the shroud, went for normal 5 mile cruise route, outside temp. about 90, hoping for the best, and the damn car did exactly what it's been doing! 200 on hwy. and up to 230 in about 3 minutes when you get under 1,000 RPM. I was most surprised that the aluminum Rodney Red didn't lower my temps. any, whatsoever. If I'm setting still in the driveway and boost the RPMs up to around 1,800 it will start dropping the temp. quickly to about 210. My original fan was a 18 in. Flex Fan so I took advice from this site and installed a Hayden #2797 Clutch Thermal Fan and a Hayden #220618 steel fan about 2 months ago and it made no difference with the overheating problem.
So, where do I go from here? I don't know if my temps. drop when you increase the RPM because the fan is drawing more air through the radiator or is it because the water pump is turning faster? How can you tell the difference?
Needless to say I'm very frustrated and don't know what I should do next. I've read every post on this site about overheating and it appears I've done about everything there is to do. If lack of airflow at idle is causing my problem I'm tempted to order a 18 in. Derale #17018 Flex Fan because I've read a lot of good things about it here. Should I ditch the Flow Kooler water pump and try to find a cast impeller NAPA #58-299, 8-bolt water pump, tweak the divider plate the way George K. details, and hope for the best! I've read some positive posts about electric fans but there are some negative posts as well. I really thought, and hoped, that the Rodney Red would solve my overheating problem but it didn't. Sorry for the long post but I would certainly appreciate any help, advice, or suggestions any of you can provide with this matter. Thanks!

[Bill H]

You really have a problem!!
I'm not any kind of expert but I would try advancing the timming a little at a time and see if runs any cooler. I run my 67 about 12* initial with a 400/2801 cam/3:55 gears and a RR. Run runs 185 on the highway all day long. I screwed up and retarded the timming last week and temps went up most rapidly to over 200. Got my timming re-set correctly for my combo and it runs cool again. Just a thought !!!

I have a flex fan and no shroud, had bad luck with fans and shrouds, see my pics on previous thread a couple of post down. Bent fins on alum. rad.
Hope you find a fix soon

[Bruce Meyer]

I would say your total timing is good but your retarded at idle. I would like to see around 12 degrees timing at idle. You also might want to try hooking vacume advance to direct manifold vacume. That will give you more timing at idle without affecting total. Flex fan will probably do nothing for you. Also you might want to try less antifreeze ratio. Straight water cools the best. You can always add anti freeze when winter comes.

[Blue '66]

The Rodney Red should have made some difference.I would get a new temp gage or a handheld that came check the temp of an object to see if the gage is correct.

[pontiacphil]

Yep, I'm so anal I have now installed 3 different sets of gauges and they all read the same. Plus, you can feel the excessive heat under the hood when it gets in the 220 to 230 range. When I open the cap, and watch the coolant/water mix, it opens and starts a good flow at 185 degrees (it's a 180 thermostat). I still think it's either air flow at low RPM's or the water pump isn't pumping much at low RPM's. The Flow Kooler pump I bought through Summit says it pumps 30% more at low RPM's but I'm not sure that isn't just advertising hype. I truly thought the Rodney Red aluminum radiator would have to help some, just being aluminum, but it didn't make a degree difference over the factory 4-core Harrison. I really thought that would be my solution and was greatly disappointed when it didn't help me. I just don't know what else to do at this point. My dobber is down! I tried both the port and manifold vacuum methods and the overheating remained the same. No difference.

[george kujanski]

SOme crazy questions: since you have the 8 bolt pump, do you have the divider plate in there? Any trapped air? Gauge accurate?

How about leaving the cap off the radiator and observing coolant flow at idle, when it opens?

There must ba an answer...Try adding a box fan in front of the car when idling to see if the xtra airflow helps.

Maybe post some pix of the shroud/fan setup?

George

[Matt Meaney]

boy, does this sound familiar. after rebuilding a 455 for my 72 lemans, pretty much the same thing happened. had the radiator bioled and flow check, then installed a new desert cooler rad (4 core), a 160* t-stat, two different clutch fans, one new replacement clutch for the fan, two different afermarket flex fans, an electric pusher fan in front of the rad (made it run hotter), finally put in a factory 5 blade flex fan (non a/c style no clutch) from a 72 350 ventura with a spacer that put the blades half in half out of the shroud. bingo! 175-180* all day long in the summer heat. another idea would be the pulley diameter with the aftermarket pump. it might be spining it too fast or too slow, both arn't good. just some more ideas. hope you get it sorted out soon, so you can start enjoying it.

[DBONES152]

There are 3 things in your original post that are very suspect to an overheating problem.
1. Your initial timing at 7* seems too low. I would advance it to about 12*.
2. Make your idle air/fuel mixture richer.
3. Start using a higher octane fuel. I buy 93 octane and add 110 racing fuel at about a 4 to one mix. There are also several brands of octane boost available although I have never tried them.

[Lemans1]

Another thing to check is your air/fuel ratio. An engine running lean will run hot. I had a car that had a similar problem. After I jetted the carb up and reset the timing, the temps came down almost 15 degrees. Just one more thing to check. Good luck!

[Lemans1]

Another thing to check is your air/fuel ratio. An engine running lean will run hot. I had a car that had a similar problem. After I jetted the carb up and reset the timing, the temps came down almost 15 degrees. Just one more thing to check. Good luck!

[BILTIT]

Anything left in the timing cover holes from painting engine? Ask me how i know!

[pontiacphil]

Geoff, I have tried both and the overheating stayed the same. I used the manifold by hooking into the small hole the factory used on a 68' intake just in the front rt. corner of the carb. Idle jumped up and I developed a flat spot or stumble when I gave it gas from idle to a faster speed. Overheating problem wasn't affected. I'm now running ported vacuum off the Quadrajet carb. It's so hot here in Tn., and guess that I'm too old, as the high temps. have kept me away from working on my car for a day or two. This Crower #60242 cam doesn't really seem radical enough to warrant using a vauum canister. I've got a 2,000 stall in the car and lack of vacuum sure isn't noticeable. I could be wrong however. I ordered a Cardone #58299 water pump form O'Reilley's
yesterday and plan to order a Mr. Gasket high flow 160 themostat, I'm running a 180 presently, and drill the 4 small holes that have been discussed here. I'm going to take off the new Hayden clutch fan & blade and go with a 18 in. flex fan with 2 inch spacer. I can't decide whether to order the Flex-A-Lite #1818 or the Derale #17018 as both get get comments here. I called Flex-A-Lite Tech. line and they weren't real optimistic about getting much more air flow at idle RPM's. Tried to call Derale but they didn't have a phone # and couldn't even E-mail them as the have a "spcecial" e-mail acct. that you have to register and sign up for. Too much of a pain to do. If anyone can help me with deciding between the 2 fans I'd like to hear your comments. Bobbyj1 has had such good luck with the Flex-a-Lite I'm swaying towards that one. Any other suggestions, tidbits, advice etc. will be sincerely appreciated.

[topdog1300]

Originally Posted by pontiacphil

I've posted several times in the past about my 67' GTO overheating at idle. It ran hot before my total rebuild this past Winter and it continues to do so after the rebuild. It's a stock 400 bored .30 over, forged flat tops, true 9.48 compression, 670 heads w/ 3-angle valve job, stainless valves, roller tips, Crower #60242, 3:36 gears, rebuilt Turbo 400, Pertronix HEI, Quadrajet that appears to be set correct (not too lean or rich) factory intake, 2 & a half in. exhaust, Ram Air exhaust manifolds with X-pipe, running 91 octane gas, 7 degree advance at 750 RPM idle with total advance at 37 deg. at 3,000 Rpm, Flow Kooler water pump tweaked the way George advised me to, 180 degree Mr. Gasket themostat, Ames shroud. 400 miles on the rebuild running Mobil I 5w-30 with a can of GM EOS and 20 qts. of Mobil I ATF in the tranny.
Before, and after the rebuild, the car gets hot at idle. Will run in the 200 deg. range on the hwy. at 55 mph but as soon as you drop the idle down to under 1,000 RPM it goes to 225 to 230 very quickly. I shut it down at 230 but think it would keep getting hotter if I let it run. I set the idle up to 850 but it didn't help. Had my Harrison 4-core recored and it didn't help any. I ordered a Rodney Red 8 wks. ago and got it last wk. Jerry, the owner, was a very nice guy to work with. Got it installed this morning, used a 50/50 water to antifreeze ratio. used foam to seal the gap around the shroud, went for normal 5 mile cruise route, outside temp. about 90, hoping for the best, and the damn car did exactly what it's been doing! 200 on hwy. and up to 230 in about 3 minutes when you get under 1,000 RPM. I was most surprised that the aluminum Rodney Red didn't lower my temps. any, whatsoever. If I'm setting still in the driveway and boost the RPMs up to around 1,800 it will start dropping the temp. quickly to about 210. My original fan was a 18 in. Flex Fan so I took advice from this site and installed a Hayden #2797 Clutch Thermal Fan and a Hayden #220618 steel fan about 2 months ago and it made no difference with the overheating problem.
So, where do I go from here? I don't know if my temps. drop when you increase the RPM because the fan is drawing more air through the radiator or is it because the water pump is turning faster? How can you tell the difference?
Needless to say I'm very frustrated and don't know what I should do next. I've read every post on this site about overheating and it appears I've done about everything there is to do. If lack of airflow at idle is causing my problem I'm tempted to order a 18 in. Derale #17018 Flex Fan because I've read a lot of good things about it here. Should I ditch the Flow Kooler water pump and try to find a cast impeller NAPA #58-299, 8-bolt water pump, tweak the divider plate the way George K. details, and hope for the best! I've read some positive posts about electric fans but there are some negative posts as well. I really thought, and hoped, that the Rodney Red would solve my overheating problem but it didn't. Sorry for the long post but I would certainly appreciate any help, advice, or suggestions any of you can provide with this matter. Thanks!

I have the same problem and now have ordered a anuminum radiator from Chevellecooling .co they guarantee to run 30 degrees cooler.

[topdog1300]

Originally Posted by pontiacphil

I've posted several times in the past about my 67' GTO overheating at idle. It ran hot before my total rebuild this past Winter and it continues to do so after the rebuild. It's a stock 400 bored .30 over, forged flat tops, true 9.48 compression, 670 heads w/ 3-angle valve job, stainless valves, roller tips, Crower #60242, 3:36 gears, rebuilt Turbo 400, Pertronix HEI, Quadrajet that appears to be set correct (not too lean or rich) factory intake, 2 & a half in. exhaust, Ram Air exhaust manifolds with X-pipe, running 91 octane gas, 7 degree advance at 750 RPM idle with total advance at 37 deg. at 3,000 Rpm, Flow Kooler water pump tweaked the way George advised me to, 180 degree Mr. Gasket themostat, Ames shroud. 400 miles on the rebuild running Mobil I 5w-30 with a can of GM EOS and 20 qts. of Mobil I ATF in the tranny.
Before, and after the rebuild, the car gets hot at idle. Will run in the 200 deg. range on the hwy. at 55 mph but as soon as you drop the idle down to under 1,000 RPM it goes to 225 to 230 very quickly. I shut it down at 230 but think it would keep getting hotter if I let it run. I set the idle up to 850 but it didn't help. Had my Harrison 4-core recored and it didn't help any. I ordered a Rodney Red 8 wks. ago and got it last wk. Jerry, the owner, was a very nice guy to work with. Got it installed this morning, used a 50/50 water to antifreeze ratio. used foam to seal the gap around the shroud, went for normal 5 mile cruise route, outside temp. about 90, hoping for the best, and the damn car did exactly what it's been doing! 200 on hwy. and up to 230 in about 3 minutes when you get under 1,000 RPM. I was most surprised that the aluminum Rodney Red didn't lower my temps. any, whatsoever. If I'm setting still in the driveway and boost the RPMs up to around 1,800 it will start dropping the temp. quickly to about 210. My original fan was a 18 in. Flex Fan so I took advice from this site and installed a Hayden #2797 Clutch Thermal Fan and a Hayden #220618 steel fan about 2 months ago and it made no difference with the overheating problem.
So, where do I go from here? I don't know if my temps. drop when you increase the RPM because the fan is drawing more air through the radiator or is it because the water pump is turning faster? How can you tell the difference?
Needless to say I'm very frustrated and don't know what I should do next. I've read every post on this site about overheating and it appears I've done about everything there is to do. If lack of airflow at idle is causing my problem I'm tempted to order a 18 in. Derale #17018 Flex Fan because I've read a lot of good things about it here. Should I ditch the Flow Kooler water pump and try to find a cast impeller NAPA #58-299, 8-bolt water pump, tweak the divider plate the way George K. details, and hope for the best! I've read some positive posts about electric fans but there are some negative posts as well. I really thought, and hoped, that the Rodney Red would solve my overheating problem but it didn't. Sorry for the long post but I would certainly appreciate any help, advice, or suggestions any of you can provide with this matter. Thanks!

I have the same problem and now have ordered a anuminum radiator from Chevellecooling .co they guarantee to run 30 degrees cooler.

[topdog1300]

Originally Posted by pontiacphil

I've posted several times in the past about my 67' GTO overheating at idle. It ran hot before my total rebuild this past Winter and it continues to do so after the rebuild. It's a stock 400 bored .30 over, forged flat tops, true 9.48 compression, 670 heads w/ 3-angle valve job, stainless valves, roller tips, Crower #60242, 3:36 gears, rebuilt Turbo 400, Pertronix HEI, Quadrajet that appears to be set correct (not too lean or rich) factory intake, 2 & a half in. exhaust, Ram Air exhaust manifolds with X-pipe, running 91 octane gas, 7 degree advance at 750 RPM idle with total advance at 37 deg. at 3,000 Rpm, Flow Kooler water pump tweaked the way George advised me to, 180 degree Mr. Gasket themostat, Ames shroud. 400 miles on the rebuild running Mobil I 5w-30 with a can of GM EOS and 20 qts. of Mobil I ATF in the tranny.
Before, and after the rebuild, the car gets hot at idle. Will run in the 200 deg. range on the hwy. at 55 mph but as soon as you drop the idle down to under 1,000 RPM it goes to 225 to 230 very quickly. I shut it down at 230 but think it would keep getting hotter if I let it run. I set the idle up to 850 but it didn't help. Had my Harrison 4-core recored and it didn't help any. I ordered a Rodney Red 8 wks. ago and got it last wk. Jerry, the owner, was a very nice guy to work with. Got it installed this morning, used a 50/50 water to antifreeze ratio. used foam to seal the gap around the shroud, went for normal 5 mile cruise route, outside temp. about 90, hoping for the best, and the damn car did exactly what it's been doing! 200 on hwy. and up to 230 in about 3 minutes when you get under 1,000 RPM. I was most surprised that the aluminum Rodney Red didn't lower my temps. any, whatsoever. If I'm setting still in the driveway and boost the RPMs up to around 1,800 it will start dropping the temp. quickly to about 210. My original fan was a 18 in. Flex Fan so I took advice from this site and installed a Hayden #2797 Clutch Thermal Fan and a Hayden #220618 steel fan about 2 months ago and it made no difference with the overheating problem.
So, where do I go from here? I don't know if my temps. drop when you increase the RPM because the fan is drawing more air through the radiator or is it because the water pump is turning faster? How can you tell the difference?
Needless to say I'm very frustrated and don't know what I should do next. I've read every post on this site about overheating and it appears I've done about everything there is to do. If lack of airflow at idle is causing my problem I'm tempted to order a 18 in. Derale #17018 Flex Fan because I've read a lot of good things about it here. Should I ditch the Flow Kooler water pump and try to find a cast impeller NAPA #58-299, 8-bolt water pump, tweak the divider plate the way George K. details, and hope for the best! I've read some positive posts about electric fans but there are some negative posts as well. I really thought, and hoped, that the Rodney Red would solve my overheating problem but it didn't. Sorry for the long post but I would certainly appreciate any help, advice, or suggestions any of you can provide with this matter. Thanks!

I have the same problem and now have ordered a anuminum radiator from Chevellecooling .co they guarantee to run 30 degrees cooler.

[topdog1300]

Originally Posted by pontiacphil

I've posted several times in the past about my 67' GTO overheating at idle. It ran hot before my total rebuild this past Winter and it continues to do so after the rebuild. It's a stock 400 bored .30 over, forged flat tops, true 9.48 compression, 670 heads w/ 3-angle valve job, stainless valves, roller tips, Crower #60242, 3:36 gears, rebuilt Turbo 400, Pertronix HEI, Quadrajet that appears to be set correct (not too lean or rich) factory intake, 2 & a half in. exhaust, Ram Air exhaust manifolds with X-pipe, running 91 octane gas, 7 degree advance at 750 RPM idle with total advance at 37 deg. at 3,000 Rpm, Flow Kooler water pump tweaked the way George advised me to, 180 degree Mr. Gasket themostat, Ames shroud. 400 miles on the rebuild running Mobil I 5w-30 with a can of GM EOS and 20 qts. of Mobil I ATF in the tranny.
Before, and after the rebuild, the car gets hot at idle. Will run in the 200 deg. range on the hwy. at 55 mph but as soon as you drop the idle down to under 1,000 RPM it goes to 225 to 230 very quickly. I shut it down at 230 but think it would keep getting hotter if I let it run. I set the idle up to 850 but it didn't help. Had my Harrison 4-core recored and it didn't help any. I ordered a Rodney Red 8 wks. ago and got it last wk. Jerry, the owner, was a very nice guy to work with. Got it installed this morning, used a 50/50 water to antifreeze ratio. used foam to seal the gap around the shroud, went for normal 5 mile cruise route, outside temp. about 90, hoping for the best, and the damn car did exactly what it's been doing! 200 on hwy. and up to 230 in about 3 minutes when you get under 1,000 RPM. I was most surprised that the aluminum Rodney Red didn't lower my temps. any, whatsoever. If I'm setting still in the driveway and boost the RPMs up to around 1,800 it will start dropping the temp. quickly to about 210. My original fan was a 18 in. Flex Fan so I took advice from this site and installed a Hayden #2797 Clutch Thermal Fan and a Hayden #220618 steel fan about 2 months ago and it made no difference with the overheating problem.
So, where do I go from here? I don't know if my temps. drop when you increase the RPM because the fan is drawing more air through the radiator or is it because the water pump is turning faster? How can you tell the difference?
Needless to say I'm very frustrated and don't know what I should do next. I've read every post on this site about overheating and it appears I've done about everything there is to do. If lack of airflow at idle is causing my problem I'm tempted to order a 18 in. Derale #17018 Flex Fan because I've read a lot of good things about it here. Should I ditch the Flow Kooler water pump and try to find a cast impeller NAPA #58-299, 8-bolt water pump, tweak the divider plate the way George K. details, and hope for the best! I've read some positive posts about electric fans but there are some negative posts as well. I really thought, and hoped, that the Rodney Red would solve my overheating problem but it didn't. Sorry for the long post but I would certainly appreciate any help, advice, or suggestions any of you can provide with this matter. Thanks!

I have the same problem and now have ordered a anuminum radiator from Chevellecooling .co they guarantee to run 30 degrees cooler.

[pontiacphil]

At 5 pm today I pulled my GTO out of the garage and put it in the shade of the driveway. About 90 degree temp. Started it up, let it idle at 825 RPM for 6 minutes with a 20 inch box fan blowing through the grill. It hit 230 and I shut her down and let it cool down to 180.
Advanced my 7 degree at idle timing (plugged the vacuum advance off) and got it set at 12 degrees advance at idle. No box fan used. In 6 minutes it was back at 230 degrees. Everything in this motor is new or rebuilt. Hot tanked, dipped, cleaned by a very reputable machine shop. I'm at a loss as to what to do next. The 8-bolt timing cover was a bit pitted and corroded. Could this cause an overheating problem? The divider plates were in very good condition and I tweaked them to George's specs. for clearance. I can buy new stainless divider plates off E-Bay if anyone thinks that might help. I did get my Cordone #58299 water pump at O'Reilley's today ($24). Got a factory 160 thermostat and drilled the 4, three-sixteenths holes in the outer edge. I never got any responses here about which 18 in. flex fan, the Flex-A-Lite or the Derale is best so I think I will order the Flex-A-Lite from Summit with a 2-inch spacer and use my Ames shroud. along with the Rodney Red. If this doesn't solve my overheating I really don't know what else to do. Wish me luck. Any suggestions?

[70GS455]

"...The Derale heavy duty flex fan is a newly designed series that outperforms any clutch fan assembly and does not have the downsides of the old designs. It features full support blades, hardened metal centers and full rivot stainless steel blades (not aluminum or steel). They are good for over 8500rpms and will NOt fling blades and pull about 33% more air thru the system and use a fraction of the hp up top.

Fixed bladed fans can take up to 40hp+ to fling around and even 30ish with a clutch. The new technology Derale takes less than 7hp at full tilt because it gives up it's "biting" attitude at high rpms...."

One thing to consider, if you have enough room between the radiator and fan, and you can fit one, you might be able to put a slimline electric fan inside the shroud, between the rad and mechanical fan (my Dodge truck uses this setup). Spal or Derale make some 2" or 2.5" thick electrics that might help with the idle airflow issue.

[slickman]

You stated you just had the engine rebuilt, is it a 455? I heard someplace that if you got too far with the boring (not sure if it was over .030 or .060) on a 455 you could have overheating problems. Can you expand on what was done with the over bore?

Originally Posted by pontiacphil

At 5 pm today I pulled my GTO out of the garage and put it in the shade of the driveway. About 90 degree temp. Started it up, let it idle at 825 RPM for 6 minutes with a 20 inch box fan blowing through the grill. It hit 230 and I shut her down and let it cool down to 180.
Advanced my 7 degree at idle timing (plugged the vacuum advance off) and got it set at 12 degrees advance at idle. No box fan used. In 6 minutes it was back at 230 degrees. Everything in this motor is new or rebuilt. Hot tanked, dipped, cleaned by a very reputable machine shop. I'm at a loss as to what to do next. The 8-bolt timing cover was a bit pitted and corroded. Could this cause an overheating problem? The divider plates were in very good condition and I tweaked them to George's specs. for clearance. I can buy new stainless divider plates off E-Bay if anyone thinks that might help. I did get my Cordone #58299 water pump at O'Reilley's today ($24). Got a factory 160 thermostat and drilled the 4, three-sixteenths holes in the outer edge. I never got any responses here about which 18 in. flex fan, the Flex-A-Lite or the Derale is best so I think I will order the Flex-A-Lite from Summit with a 2-inch spacer and use my Ames shroud. along with the Rodney Red. If this doesn't solve my overheating I really don't know what else to do. Wish me luck. Any suggestions?

[pontiacphil]

Had a reputable machine shop bore it 30 thousandeths over so it's probably about a 406 now. I'm sorry to say the new Rodney Red radiator did not solve my problem. Same temps. as my stock 4-core Harrison. I did replace the new Flow Kooler water pump with a Cardone and hammered the divider plate to such close tolerances that the impellers were just about dragging against the cover! Took off the new Hayden clutch fan and blade and replaced it with a 18 in. Flex-A-Lite fan using a 2 inch spacer like BobbyJ1 recommended. Removed the high flow, Mr. Gasket, 180 thermostat and put in a stock type 160 one with the 4 small holes drilled around the edges.Took Screamingchief's advice and used a VDV in my vacuum line after I went from port vacuum to manifold vacuum. Running 12 degrees at 825 rpm idle with a total of 38 degrees. After all this, the weather has dropped about 20 degrees here so I can't really compare apples to apples as to how much cooler it is running. I do think it has helped as it now runs about 170 at hwy. speeds and around 190 to 200 setting in my driveway. I have not let it idle for 15 to 20 minutes as I'm so gun shy, and tired of fighting this problem, that I just don't want to be disappointed if it should climb back up into the 220 to 230 range. Maybe I'll get over this and try an extended idle and hope for the best! Like I said, that's with an outside temp. of 70 degrees while back in the, Summer when it was running in the 220 to 230 range, it was 90 to 95 degrees. Everyone here has provided a lot of info. and suggestions which I am grateful for. I THINK my overheating may be solved by all of the things that I listed above. Seems that you just have to get the correct combinations of several parts and hope for the best. Sorry for such a long post but I just wanted to be specific in what all I had done to cure my problem. Thanx.