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convinced of a overheat problem. thoughts? what should I do?


Crazy K

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this is on my 95 hybrid... 3100 crate motor installed sometime in the less driven more recent years of it's life.(I assume around...say 73,000?) Right now the car sits at 109,000 miles, and the engine is always running hot. great winter car BAD summer car.

 

in the time I've had it, I've replaced both new temp sensors, the tstat twice, the heater core, and flushed the system twice. The issue: the gauge always reads high and the car has never turned the fan on. (fans and relays do work) the guage has always hovered around the second peg line, and advanced past that just short of the red... and never turned the hot light on until tonight.

 

today I replaced the water pump, and removed and flushed the radiator with some drano in a bath tub, put it all back together for now.

 

tomorrow i will swap to a THIRD T-stat, which I know works great, as it has been doing service in another car, and swap the ecm temp sensor for a known good one, and I'm considering replacing the guage temp sensor, which might need a donor from a 95 in the yard. I'd like to even test the temp gauge by swapping in the cluster from the 95 3.4 dohc car.... except it's stored 20 miels away :P

 

 

does this sound like I am on the right track?

 

How would I go about checking if there is exhaust intermingling with the coolant? I do/have not see bubbles coming up in the coolant, nor do I see air gathering in there... although it could be be output through the overflow?

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Put a 180* stat in it and see what happens. My Lumina runs warm with the 195* stat in it, but the fan(s) kick on when the gage gets to half and brings the temps back down.

 

So, when the warm light came on, did your fans turn on? I feel there is something definately wrong that the fans aren't coming on when they should be.

When you are cruising down the highway does the car continue to run warm? What condition is the radiatior in? Rad might not be as effective as it should be...

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So, when the warm light came on, did your fans turn on? I feel there is something definately wrong that the fans aren't coming on when they should be.

When you are cruising down the highway does the car continue to run warm? What condition is the radiatior in? Rad might not be as effective as it should be...

 

fans never turned on

 

WHen I am cruising down the highway, the gauge usually reads short of the upper limit normal mark, about the same distanace from the mark as the red is in the opposite direction.

 

the feeling of the engine being hot was not there until the weather warmed up. now it just begs and screams "I'm hot" but I'm not certain if it is really as hot as it claims... but.... thats part of what I am trying to figure out.

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Ken, I would confirm that the temperature gauge is accurate by measuring the temp with a thermometer, infrared pyrometer, or with whatever other temperature device you can get your hands on. I've seen temperature gauges in clusters fail and give off higher readings than normal(my dad's '92 Mustang did this last summer, it would show 240*F after idling in traffic on the stock gauge despite the coolant temperature never going past an actual 180*)

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Ken, I would confirm that the temperature gauge is accurate by measuring the temp with a thermometer, infrared pyrometer, or with whatever other temperature device you can get your hands on. I've seen temperature gauges in clusters fail and give off higher readings than normal(my dad's '92 Mustang did this last summer, it would show 240*F after idling in traffic on the stock gauge despite the coolant temperature never going past an actual 180*)

 

if i had a thermometer.....

 

well the fan did turn on today.

 

coupled with the fact that the a/c is not working right now, the fan would turn on at a higher temperature with the a/c off than with it on. I may still have a probelm, but I think I'll be doing the items I mentioned... but another issue with a different vehicle has come up... so I'll have to finished swapping things around in a bit.

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  • 1 month later...

well well well how would you fix this? I went through this bs and replaced the temp sens. Both of them plus the 180 stat. Would you need to get a new cluster? Can just the gauge be replaced? If a new cluster needs to be put in how do you justify your current mileage?

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I correct the odometer. very simple and easy. aka rolling the mileage, but I'm doing it to keep the reading the same.

 

turns out the first cluster seems to read high, and a computer scan of the car shows temps to be normal when running, even when the gauge is high. so bad on bad made it look really bad. I have not replaced the sensor yet, after all it is a brand new and defective POS Wells sensor.

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FYI: the guage temp sensors always read on the hot side. I dont know why either. But from all the flushing of the system that youve done, you could still have an air bubble sitting where that guage is making it read hotter than it should on top of something that already reads hot.

 

for example, we had my dads tools hooked up to my car. The guage temp read ~200degrees. On the ECM side, the coolant was only ~185degrees

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yeah I keep the scanner hooked up because it makes me look more sophisticated like I know what I'm doing but yeah my temp is normal on the scan but the gauge is way over. That is no longer possible to have any air bubbles floating around in there. It's been on the road at over 70mph for hours and hours. Don't tell me air can sitll be trapped in there. The valves keep getting opened to let what ever air is still in there. If your replacing the cluster with junk whats the point? Maybe a 96 cluster would work with me or something newer. aka NEW. aka 2007

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Do yourself a favor and swap to the single 3-wire temp sensor, which runs the gage and the PCM readings. It was the only way I could get a normal reading on my '95.

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Do yourself a favor and swap to the single 3-wire temp sensor, which runs the gage and the PCM readings. It was the only way I could get a normal reading on my '95.

 

thats my plan! :)

 

doesn't seem to be a problem otherwise. :P

 

I DID do an ohm test on the sensor and the values appeared ok. 3 wire, here I come!

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did you by chance bleed the system?. that can screw up alot :mrgreen:

about 254,345,909,495,243 times! This car has a pinhole in the T-stat due to the issues I've had, the pinhole hurts nothing but makes bleeding supereasy.

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Do yourself a favor and swap to the single 3-wire temp sensor, which runs the gage and the PCM readings. It was the only way I could get a normal reading on my '95.

 

 

I always hated that one wire sensor. They leave it out and it's surrounded by an inferno with temps hotter than the surface of the sun. What would be the replacement part for doing the swap? I've never heard of nor come across anything like it. Is the three wire by the stat got the same fit? I don't get it explain. The sensors in my POS are all new and the hell with the pressure relieve valves. That is such a load of crap. Everyone must be stupid about letting the air out. :biggrin:

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96+ 3100s and 3400's got the 3 wire.

 

if you can find one in a yard it would be nice to grab the wire connecotr and even the sensor.

 

but if you must, I know the TPS plug is the same, assuming you can figure out how to wire it up.

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