Overheating/Thermostat

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TheOGway

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Now, I've got a couple things going on with my 88 Bronco XLT. One of them, the main thing, is an overheating problem. I was living in California and it's always hot there so after about 30 mins of driving it starts to overheat. Once I get where I'm going there's hissing in the engine somewhere and I haven't found where it's coming from...I think it's the radiator hose. I got a new radiator but I haven't switched the hoses so that COULD be a problem, right? My main question is, my Bronco doesn't have a thermostat...could that cause my overheating problems? What else could be causing it? I also have a jittering or jerking when I come off a stop, once I hit the gas it jerks a little and sometimes feels like I'm not getting full power. I'm in GA now and I'm getting my truck back soon so I want to know what to work on once I get it. Thanks for the help in advance!

 

miesk5

96 Bronco 5.0
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yo T,

WELCOME!

I assume you have been adding coolant mix of 50% with clean water?

This is by Ford, Richard S, Deanna S & others.

"The mechanics have a device called a cooling system pressure tester. This allows them to create artificial pressure to test the system for leaks. It also allows them to test the pressure cap to make sure that it will retain the proper amount of pressure in the system. I know it may sound odd, but this might be nothing more than a loose clamp or at least we can hope that it is. The test will reveal your problem and then you will know what you need to deal with." by Richard S, An ASE Mechanic.

The first thing to check if your vehicle overheats often is the radiator cap. Sometimes the gasket on the cap deteriorates and lets pressure escape, which causes the cooling system to malfunction. Most service stations can test your cap for you and tell you whether it’s in good condition. or diy Pressure Test by Ford in a 96, but similar to your 88 @ http://www.diesel-dave.com/vehic/manual/stj/stj33014.htm#extract_573

and see http://www.aa1car.com/library/coolant_leaks.htm

"Leak detection dye can also be added to the coolant itself to make a slow leak easier to find. Some of these dyes glow bright green or yellow when exposed to a UV light source"

and the pressure test video @


Here are some issues that can cause a vehicle to overheat:

•Visually inspect hoses & clamps;

And A/C condenser core and radiator for obstructions, such as leaves or bugs

•Late timing: If your ignition system is malfunctioning, late timing (any pinging while accelerating?

may be causing your vehicle to overheat because the spark plugs are firing the fuel/air mixture after the piston moves back down from the top of its stroke. Late timing alone doesn’t cause an engine to overheat by more than a few degrees, but when coupled with other problems, it can bring the engine temperature to a critical point. Have a service facility place your vehicle on an electronic diagnostic machine to check your timing and adjust it if necessary.

•Plugged radiator: Because plugged radiators cut down on the system’s liquid circulation, the system can’t cool efficiently. The remedy is to have a radiator specialist remove and inspect the radiator. If you’re lucky, just steam-cleaning the radiator does the job; if you’re not, the solution may be more expensive.

•Slipping accessory belt: If you can see and reach the accessory belt that drives the water pump, check to be sure that there’s no more than about 1⁄2 inch of give. If the belt seems loose or frayed, you can try to replace it. If you can’t do the job, have a professional deal with it.

•Collapsing bottom radiator hose: Occasionally, a bottom radiator hose begins to collapse under the vacuum that the water pump creates, and the impaired circulation causes overheating.

Fan clutch is a coupling device that is located between the water pump shaft and the fan. The fan clutch is designed to improve the vehicle’s cooling system efficiency while reducing the load on the engine and loss of energy caused by the fan itself. The Fan Clutch allows the fan to operate at lower speeds and effectively detach at higher speeds when the vehicle is moving and air movement due to velocity aids to cool the engine.

freeze plugs leak; hard to see though without apply the pressure tester and sometimes the dye.

Heater core - any signs of maple syrup aroma in cab or wet passenger carpet?

•Low oil level: A vehicle that’s low on oil tends to overheat because the oil removes from 75 to 80 percent of the “waste heat” in your engine (in addition to doing its other job of cushioning the moving engine parts).

If you’re one quart low in oil and your vehicle holds five quarts, the oil will carry away 20 percent less heat than it should.

"

intake manifold or head gasket

Overheating problems due to the head gasket may be due to the Head gasket having a break in it. Depending on where the break is, you may not see coolant in the oil but the hot coolant may be mixing with cooler coolant and raising the temp. Or possibly the coolant may be entering the combustion chamber and it is burned off resulting in the need for more coolant. If coolant is entering the combustion chamber you may not see it if there isn't much passing through the head gasket however it can still affect temperature. In mild cases you can buy some time with some sort of leak stopping additive.

Overheating problems due to the head gasket may also be due to a break in the head gasket that is allowing combustion gasses to be pushed into the coolant. Depending on you engine configuration and the location of the water pump, the result could be trapped air in the water pump. Air can get trapped in a water pump stalls the pump and because automotive water pumps are not "air tight", they cannot always self prime. This could also explain a loss of coolant. As the engine cools and when the engine goes through the exhaust stroke, coolant is pushed into the combustion chamber. Some guys I know ran without the cap to hopefully allow the water to not build up pressure and push back into the cylinder but usually the result of that is a lack of "back pressure" in the coolant and the combustion gasses leak into the coolant at a faster rate. Apparently there are better water pumps to prevent air from stalling them. A guy I know would stop his car and wait, sometimes he tried rocking the car to get the air bubble out of the water pump, then start it up again and it would cool quickly. Ultimately a head gasket replacement is necessary. Again some sort of stop leak may help and buy some time.

Head gasket condition can be inspected by checking the compression pressure with a pressure gauge, or better yet, a leak-down test. Also note any indication of combustion gasses in the cooling system. Oil mixed with coolant and excessive coolant loss with no apparent cause, or presence of carbon monoxide or hydrocarbon gases in the expansion tank of the cooling system can also be signs of head gasket problems. Driving with a blown head gasket can cause additional extensive damage due to overheating or loss of lubrication.

 
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TheOGway

TheOGway

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Thank you so much. I will look into all of these things!

 

miesk5

96 Bronco 5.0
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yo OG,

yw!

btw, Most parts stores have a Loan a Tool program where you can "borrow" the Pressure Test Kit for a hefty, but fully refundable deposit; ensure rad cap Test accessories are included.

 

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