Hood vents won't make much difference. Spike monitored temps and found they hovered around 150F, even though IAT swings around a bit.

Here is what I found out testing today while running errands, flat ground. Morning run about 35 miles, below 90F outside. 183-187F 180F stat Went up to 198 in town.

Parked at Tractor Supply, left running with AC on for college student offspring inside. Pulled out rubber strips around rad on 3 sides. Came back after a few minutes and is was 228F. Dash gauge still about 8:00 (97 D1).

Drove off. Temps got back down to 196. An hour earlier on same road was 185. Stopped and put rubber strips back in after five miles. Temps went down to 192-194. Drove 30 miles. Shopped, then started back home. Clouds had rolled in and temps had dropped into the 80's from the mid 90's. Ran 183-185 25 miles home, with AC on; all this at around 60 mph. Only thing that changed was outside air temp.

After cool down, check coolant and oil, normal levels.

Remove top plug on radiator. I had noticed a white powdery stuff on the plug when I was putting engine back together during a very long head gasket job, had engine hoses off for more than a month. Noticed white powder coating inside some of the hoses as well. So I was running some national brand radiator flush that you leave in and drive with, been in maybe 200 miles.

Today plug had a residue on the back, would not easily rub off, but came off when scraped with a blade. So flush has done something, just not enough.

So I have put in a good quantity of Cascade dishwasher liquid, and running at idle for half an hour, and will leave in over night, before flush tomorrow with distilled, and go back distilled with water wetter; and report back.

Basically, my radiator is great below 90F on the highway. Only thing I can figure is new sludge in rad, and I just don't have enough effective radiator. It was rodded out within past 2 years. It is like I pass a thermal "knee" and the system gets a lot warmer even though now difference in load on the engine.

Put in the Cascade, drove twenty miles, engine off, checked rad temp top to bottom, about a 25 degree swing. Not happy, since two months ago it was five degrees difference. Idles at 178, 60 mph at 183-185 with AC on, but it is cool this evening. Going to leave Cascade in, and drain and flush with distilled in AM.

Wish I had a bigger radiator that could eaily be sourced at the boneyard.

 

I have the same white substance as well. Not oil though for sure. Very curious as to if that works. Feeling like maybe my rad is clogged up too.

 

Clogged rad not good if you live within 100 miles of the Mixmaster....

 

Just realised my cooling fan is direct drive.....there is NO clutch on it. don't know if good or bad........don't know if this is a common thing but figure it could probably help someone on here.

 

My mistake, didn't notice the "OBD1."

 

I have been flushing my rad this morning. The overnight Cascade treatment did not clear everything out. A gooey scum and gray sand was found in the coolant bottle, would not wash out with water. That must also be present in the rest of the cooling system. Removed bottle, washed with oxiclean, no help, then mild hydrochloric acid, most scum gone. Have flushed radiator reverse, soaked rad only with diluted hydochlroic acid, flsuhed again, put cooling system back together, idle engine, put water in top inlet of rad until water out the top hose runs clear for several minutes.

Headed to store for 10 gallons of distilled water for final flush and refill with d water and water wetter.

 

What effect would the current placement of the factory mounted transmission cooler have on increasing the temperature of the fluid in the radiator ? My thought is the trans cooler is mounted directly in front of the A/C condenser fans, if you turn the A/C on the fans come one and draw the heat coming from the trans cooler into the A/C condenser that heat is transferred to the radiator. Does this or would this make any sense as to why engine temps increase with the A/C running.

 

Seems like the air flow from forward motion would also move that heat to the rad, and the automatics also have tranny juice circulating in the driver 's side of ther radiator, and oil cooler on the passenger side.

I think the extra heat is exactly what you feel at home outside when you place your hand near the outside AC unit, a blast of hot air that has been moved from inside to outside by the modern miracle of refrigeration. You will see some commercial trucks and construction gear with an outboard condenser and fan for the AC, just not mounted in the air flow for the engine radiator.

BTW, with all the shade tree flushing I could muster, and running distilled water with water wetter, I still crawled up to 221 at idle. In 95F. At night, when cooler, it only got to 208F at idle. I'm able to drive at 50-60 with AC on and maintain 180-187F, day or night, so that is an improvement. I think I went from 30 degree swing on radiator to maybe 20. Will be calling rad shop to see if they can rod me out again..... Not happy, since within the past two months I had only a 5 degree swing top to bottom on the rad. Guess letting it dry out during HG work was another screw up.

 

I was in the same boat until about a month ago. Given that I live in CO and our outside temps still amaze me (I'm originally from Texas)...

After a really bad trip back from Moab in mid-April I came back home to do the following:

New 180 t-stat
New fan clutch (heavy duty, sounds like an airplane is taking off)
CLR in the radiator - and only the radiator - overnight

Since all of this...my temps are normal now. Heading up I-70 from Golden at 70mph (yes really) my temps will peak at 192 and then back to the 183 range. This past weekend a buddy & I did some wheeling up over Red Cone down into Montezuma I hit 212 as I was going about 5 mph through the rocks, while climbing. Given that I'm really working the engine - and it's basically stop & go as you're climbing.

I'm almost now to the point that I don't feel the need to keep a gallon of coolant & gallon of distilled water with me when I go out wheeling...almost.

 

Just make it all distilled water, which you can drink to survive, or mix with adult beverages as needed.