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Username Post: Over Heating        (Topic#359059)
Posts: 14

Reg: 09-07-17
12-07-19 09:16 AM - Post#2781650    

hi all been having a problem with overheating on the ol 235 it only does it on start up from cold when not used for a week or so , the temp guage will keep climbing , i keep waiting for the thermostat to open and let water through into the top hose but it just stays cold and guage will rise to boiling point if i let it, what i found today was if i let the pressure off in the radiator with the safety lever on the rad cap i get a gurgling in the block and hot water is then let through from thermostat to rad and the temp guage will drop nicely once ive been through this initial process i can drive her with no further problems , rad, water pump, thermostat, hoses and rad cap all new any ideas? thanks


"9th Year" Silver Supporting Member
Posts: 368
Loc: Chicago
Reg: 01-03-13
12-08-19 07:54 PM - Post#2781749    
    In response to stoveboltshane

Here’s a stab at what possibly might cause the symptoms you describe:

If the water level is a little low, just below the level of the thermostat when cold, the thermostat won’t sense the heat, won’t open. Then when you relieved air pressure it caused some turbulence and water to hit the bottom of thermostat, and it opened. Why that would only happen after sitting a week I can’t explain, unless latent heat from yesterday’s drive kept the water expanded just enough, just high enough to touch the thermostat.

I’m stretching here; somebody else will probably have a better explanation.

Posts: 370

Loc: Central Wisconsin
Reg: 01-16-14
12-08-19 08:02 PM - Post#2781752    
    In response to JayChicago

Before starting the engine have you checked the coolant level after the car has stood for week?

Posts: 838

Reg: 12-09-07
12-08-19 08:22 PM - Post#2781755    
    In response to stoveboltshane

Entirely possible it is a stuck thermostat. You can easily check that by removing it and putting it in hot but not boiling water and see where (if) it opens. Can also drill an 1/8" hole in the t-stat to create a bypass to prevent air pockets. Last RAISE the front end up on a jack while filling and let it run with the radiator cap off until the thermostat opens. If both heater hoses are hot your t-stat should be open. Gravity will help move any trapped air. Keep an eye on the coolant and see if there are bubble or steam coming out which could be a sign of a blown head gasket. You can pull plugs and see if any are rusty in appearance which would tell you water is getting in that cylinder. Do not fill the radiator all the way to the bottom of the filler neck, leave about a 1/2-3/4 gap. If you fill it all the way up the first few times you drive it will puke some coolant out the overflow tube as it seeks its own level. If you will it all the way up the coolant has nowhere to go when it gets hot and will end up on the ground from the overflow tube. Good luck. Let us know what you find.

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Posts: 14

Reg: 09-07-17
12-14-19 01:56 PM - Post#2782151    
    In response to stoveboltshane

all ok now i read somewhere on line some one had drilled a 4mm hole in the thermostat to release air that may be trapped , did it took her out today didnt over heat on start up , runs at half on the temp guage instead of quarter , but goes no further , im happy with that


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