97 Sunfire Over heating fix

hipnhappy

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Greets all,
Picked up a little sunfire for some work I did, she has sat for over a year and was recently implanted with a new head gasket and a valve job before it sat. I was told she blew a head gasket and because of a crack the head was replaced, new valves installed and after the reassembly was still having the overheating issue. A new fan and motor was given to me with the car and I was told the radiator was flushed with a garden hose so circulation in it does not seem to be the issue.
On first run through checking everything before I made a game plan, I made sure she would turn over. Replaced the battery and spayed just a splash of marvel mystery oil thinned out with some gasoline into each cylinder and let her set while I surveyed else where. Got no "priming" noise from the fuel pump, checked the relay, got power, fuse was good, indicating probable bad fuel pump. As the gas companies have had to yield to environmental pressure and added ethanol to gasoline mixes, it actually adds "water" vapor inside the tank. Once the tank gas evaporates the moisture remains and any fuel pump that sets for a year with moisture on it more than likely freezes up and the impeller won't pump. I ordered one online (found one through "Parts Geek" .com for 120 bucks shipped) and am getting ready to do that install now.
I got on and made this post mainly to share the overheating fix I'm doing as I found a great tip somewhere when I was researching the issue a few weeks ago. I didn't lock in the location but here is a cut'n'paste of the information I'm relying on to do the fix.
"My grandson was having the same problem with his 97 sunfire. He was also having problems with the fan not comming on.This is what I did and it seamed to have fixed it. Drain enough water out to take the thermostate out,it's located in the bottom radiator hose by the water pump two bolts. I went to the hardware stoor an bought a rubber o ring (44mm ID x 52mm OD x 4 mm thick) put it in the metal bracket that the bottom hose is fasten to.replace the bolts and tighten. On the top radiator hose where it comes out of the engin, romove the hose from water out let, remove the three nuts and remove the water outlet.Go to a parts house and buy an older model outlet (OReilly Auto Parts store part #84997 Murray brand) Or what ever they sell.It should be flat on the back, Buy a new rubber seal that goes on the thermostate . Install the thermostate in that opening, it's made for a thermostate (for some reason the factory changed it)install the new water outlet tighten the three nuts replace the hose,make sure every thing is tight, fill with antifreeze,I used prestone (don't buy 50/50 buy one gallon and mix it this way you can have two gallon for the price of one)start it up let it warm up untill the temp. gage shows normal,shut it off let it cool recheck the antifreeze.
I Wired the fan so it would come on when you turned the key on. There is some larger red wires that goes to the fuse box in the engin compartment with a vote meater and by turning the key off and on you can locate it splice it into that wire and the blue or green wire on the fan. The fan will run all the time but that won't hurt it.Sence we did this we have driven all over town and over 100 miles on the hiway and the temp. gage never move off normal. Hope this helps My name is Tom."
Like I said, don't remember WHERE I got this but, the reasoning is sound and it was "tested" and appears to be sound advice. I'm doping step by step pictures and will post them later. Only thing different I'm going to do is start out replacing the "temperature gauge sensor" on the side of the head where the Thermostat is going to be relocated and NOT hot wire the fan right away. I'm figuring the thermostat SHOULD start opening more accurately located on the head and that the new sensor will kick in the fan as it should. With the gauge working correctly, this should be easy to monitor. I can always wire it direct at a later time if it fails to kick on and cool correctly.
I have to change out the fuel pump first before I can get to the temperature issue, but, I did this first so that the cylinders can soak in the MMO while I'm changing it out.
I'll get back with pics and my results asap and without "Murphy's law" making any appearance, she should be running just fine.
More to come.
hipnhappy
 
Welcome to the forum and thanks for signing up. Seems to me GM spent lots of money designing the cooling system and these kind of modifications should not be necessary. Since you appear to have not even started the car yet I would first confirm that when the engine reaches the 215 to 225 range the fan motors come on bringing the water temperature back down to the 195 to 200 range.
 
Thanks Megs

Good to know, the old days of 165 thermostats and cooler running motors are gone :( I guess considering what they manage to get out of these things it shouldn't be surprising the revolutions are replacing the physical power of the bigger bore motors.
I'll jot these digits down and refer back to them once I'm running it for temp readings, hopefully the gauge will be reasonably accurate I know they generally are and always prefer them to an idiot light.
"when the engine reaches the 215 to 225 range the fan motors come on bringing the water temperature back down to the 195 to 200 range."
Got rained out this afternoon on the fuel pump replacement, guess I'll tackle it tomorrow. Will keep everyone advised.
BTW, do I need to secure permission to post pics? Got some basic ones of the thermostat location swap and will prolly have some from the fuel pump change out, some sites require permission from the mod to post. Let me know, thanks !
hipnhappy
 
Post the pictures and I may have to approve them.
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Confirmed so far

Alright, came back to this post before I go over and update my more recent one to report that thus far the "relocation" of the thermostat works very effectively.
After warming up the engine to normal operating temperature, with gauge functioning correctly, the cooling fan kicked on and reduced the temperature back within normal range well before any warning limit on the gauge.
I will report back again after the car has been "road tested". These results are with a "stationary" vehicle although I did put the engine under "load" holding the brakes on and engaging the transmission and increasing throttle to simulate engine strain and raise operating temperatures.
Will advise further ~
Otherwise, apparently a successful modification to correct the overheating condition "this" vehicle was experiencing.
 
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