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Discussion Starter · #1 ·
Here we go. My wife blew the motor in her 98 Oldsmobile intrigue, so i swapped the motors, and it wanted to run hot only on the highway with AC on. City driving, AC on or off, is fine, but highway AC on it gets hot. So, i replaced headgaskets, lower intake Mani gasket and new Plenum. Replaced all necessary gaskets to do so. I have no check engine lights on. Just a low coolant light. I know that sensor is bad, but shouldn't have anything to do with temp. It holds all fluids, no leaks, and no coolant in the oil. Could it be afaulty water pump? Faulty temp sensor? And if so, how can i check before replacing any unnecessary parts. Maybe it's something else that I'm missing? But it seems to have solid flow through both radiator hoses.... I'm stumped
 

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Discussion Starter · #3 ·
That was my first thought. So naturally, i removed the stat entirely, and that's how it is now. I put a new 180 in it, and thought maybe it was faulty. But even without a tstat it still runs high
 

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Discussion Starter · #6 ·
When AC is turned on, both fans kick on. And they both kick on once the temp gauge reads a little over halfway. I assume that's correct. I've read that if the temp sensor is bad, that it could cause the fans to come on incorrectly. Idk how true it is. And i assumed its overheating because once i hit the freeway and AC on, the temp gauge just climbs. It gets halfway between half and 3/4 before i kick off the AC.then it drop back down to 1/2. I'm so lost
 

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Discussion Starter · #8 ·
I'm gonna take it to have a pressure flush done today. I hope that does it. I wanna make sure if I'm doing it, it gets done to the best ability with as much force as possible, that way I'm not wasting money on coolant, to not get it all out. Ill let you know the outcome. Pepboys is gonna test the cap first
 

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Discussion Starter · #10 ·
I thought about a larger radiator too, but there has to be something causing this issue. And if it doesn't get fixed now, i think it'll only get worse. I run Mobil synthetics in all my cars, and they seem to really like it. I did aswell when replacing the head gaskets, i enlarged the coolant port hole, because the difference between coolaant jackets, and the hole in the gaskets, were so dramatically smaller. Every tech i talked to said its only gonna cause more coolant flow which is what i want. And it would run cooler. I only opened it to about 5/16" opposed to the pen tip sized hole that was there. And when i removed the originals, those tiny little holes had about 1/2" THICK gunk on each side. I'm wondering if someone tried putting in some coolant stop leak or bull**** in the motor before i bought it.
 

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Discussion Starter · #13 ·
No i left that coolant cap alone. I replaced the gasket, because it came with the head gasket kit, but i didn't drill that. I drilled the head gasket itself, because the coolant flow through it, was so restricted
 

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Discussion Starter · #14 ·
Everything is "operating normally".but still overheats. Could i have gunked up passageways internally in the block? Or what if its that stop leak s***? Is there anyway to get that out? Would a flush do it? I didn't wanna have them flush it, and waste anymore money. I'm stuck as to what i can do, without replacing the engine, again.
 

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Discussion Starter · #18 ·
I don't have a scangauge. But my temp gauge on the dash is reading as high as 3/4 on the gauge. I try not to let it get that high due to overheating and doing internal damage. But I'm not sure of the exact degree. But when i pop the hood, it gets HOT. Hotter than my 99 regal with the same powerplant. Mu radiator appears fine. I have all cooling fins and no damage to any of it. I'm thinking i may have a coolant blockage in the head or block somewhere. Before i replaced the motor, the temp gauge always read right on 1/2 until she blew it due to running it dry after leak occurred. I just want it back to normal lol
 

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Discussion Starter · #19 ·
Hmmm ok, so i believe i figured out the overheating. I noticed today, while ensuring there was no air in the system. That my lower radiator hose is actually collapsing about 2000+ rpm's. I've had that lower hose off multiple times and probably weakened it. With it collapsing, I'm not getting flow, therefore overheating. Does anyone know where i can find a lower hose with a inner spring? To prevent this from happening? And could this be happening because i bored out the coolant jackets on the head gasket? Allowing more flow, and its pulling to much?
 
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