I came home, the next day filled the radiator with water and let it run for a while.
You mentioned this a couple times. Water is a poor coolant by itself; it boils cooler, freezes sooner, and promotes corrosion. If you’re running much less than 50% coolant/ 50% H2O, that could explain your overheating right there.
Well I believe I forgot to put the cap back on the reservoir but it overheat on the way home. When I pop the hood the cap was off the reservoir boiling hot water and steam was coming out of the reservoir.
Well, that’s understandable. Coolant boils higher under pressure, and the typical auto cooling system operates around 5-10 PSI higher than ambient. Operating unpressurized causes the coolant to boil as it heats up; this in turn causes the hot parts of the engine to be surronded by steam, not liquid. As steam is a poor heat transfer medium, it only makes the problem worse–a feedback loop.
The next day i took the thermostat out and it still overheated.
Your original complaint–overheat when not moving–sounds like a bad thermostatically-operated fan. Has anybody checked the operation of the radiator fan? Also, you don’t sound terribly car savvy…not to criticise, just an observation. Are you certain you took out the thermostat, not the radiator cap, or even the coolant temp sensor? Removing the thermostat would entail disconnecting two rad hoses, unbolting the housing, scraping off the old gasket, and sealing everything back up with a new gasket and/or RTV. I have a little bit of skepticism you actually did all that, leading to the question, exactly what DID you do?
@insightful and @texases:
I’m still in the “we don’t have enough information” camp because of what I remember from my college days when I studied this. That was long ago, I don’t remember all of it, so this is simply to have a discussion rather than to prove right or wrong.
If we were in an engine design lab, where we could control the coolant temperature entering the radiator, the rate of flow, the capacity of the radiator, the efficiency of the radiator (simulating buildup), the air temp flowing over the radiator fins, and the velocity of air flowing over the radiator fins, don’t you think somewhere on those coolant temp curves there would be a points where the coolant temp leaving the radiator would be higher as a function of higher flow rate?
Or are you saying, even with all the other variables, that higher flow rates will always produce lower exiting coolant temps?
+1 to Meanjoe’s comments!
While the overheating problem may have originated because of an inoperative cooling fan or a clogged radiator, or possibly other factors, the OP has undoubtedly made the situation worse by using “straight” water, rather than the proper water/coolant mix.
Then, operating the car w/o the radiator cap in place just added more fuel to the fire (so to speak), and at this point, I would question the overall health of the engine in this mystery vehicle.
If it is…let’s say…a '48 Chrysler with a very stout thick-walled cast iron engine, it may have withstood all of these overheating incidents w/o too much damage. However, it the unknown vehicle is of more modern vintage–and especially if it has aluminum cylinder heads–I think that the numerous overheating incidents have likely led to a breached head gasket and/or a warped cylinder head. And then there is the issue of damage to bearings and other internal engine parts from repeated overheating.
Could the OP reveal the make, model, model year, and odometer mileage of this vehicle?
That information would help us to give advice that is more specific.
@JoeMario - Let’s put an engine in a test bed, hooked up to a radiator with a fan blowing a constant amount of air over it. Let’s use an electric motor to drive the water pump. With the engine at a set load and rpm, I’m pretty sure that the INLET temp of the radiator (once it stabilizes) will drop as we increase the water pump speed. Not in direct proportion, but higher throughput will yield higher heat exchange efficiency.
It’s the coolant temperature in the engine we’re concerned about, so that’s why I’d look at the inlet temp of the radiator. Otherwise, turn off the pump! The outlet temp of the radiator will be very low, even thought the engine’s overheating.
Some engines have a bypass cooling system and the thermostat has a plunger on its base that restricts flow to the bypass as it opens to divert coolant to the radiator. Removing bypass thermostats will cause the engine to overheat due to the coolant continuously flowing in bypass mode.
The overheating problem with removing thermostats back in the “good ole days” was that with the large, unobstructed outlet engine coolant flowing from the water pump to the outlet would form channels that followed the path of least resistance. That path would leave coolant static in areas where the coolant would actually boil away and result in isolated dry pockets where the metal temperature would rise to the point of cracking the engine, usually in the head at exhaust valves toward the rear of the engine. The temperature gauge would never indicate overheating because the sending unit would be near the thermostat in the “channel.”
“Or are you saying, even with all the other variables, that higher flow rates will always produce lower exiting coolant temps?”
Not saying that at all. Like @texases said, consider the engine-radiator system together. More circulation = more heat transfer. Another take: As circulation through the block and radiator increases, the coolant temperature throughout the radiator and block becomes more uniform and the average coolant temperature in the block must come down. Lower coolant temperature in the block means more heat transferred from the cylinders to the coolant (heat transfer proportional to temperature difference) so the radiator must be transferring more heat to the air.
@Rod_Knox’s comment about bypass t-stats is right. These are very common now. This type places the t-stat in the block where the lower (return) radiator hose connects and controls the coolant temp entering the block. The “old style” t-stat controlled the coolant temp leaving the block.
ksteed94,
You’ll have to excuse us while we argue amongst ourselves. It’s one of those things about this web site. we have opinions and like to share - sometimes quite loudly!
But to add to your situation. It sounds to me like you’ve got a head gasket problem. I had the same symptoms on my Taurus. The one symptom that always puzzled me was the fact that sitting at a light the temperature would go up, and when I started moving it would go down - and, of course, the fan never went on. I suspect that is because the fan switch is measuring “water” temp, while the temp gauge is measuring “steam”.
Nevertheless, have someone do a leak down test on the cooling system.
And back to the discussion on removing the thermostat.
I’ve had a lot of overheating problems over the years - and I’ve removed the thermostat on numerous occasions - always to no effect.
So I’m not buying that having a restriction in the cooling system is a big deal. I can see the restriction as fine tuning, but as far as the difference between overheating and not…