What are reasons for overheat?????
#1
What are reasons for overheat?????
I'm having a problem with my car overheating. I recently had the thermostat changed and I'm still having this problem. It doesn't overheat all the time, just sometimes. I would notice the temp needle slowly going past the half mark toward red as I step on the gas. When I take my foot off the gasand keep it off it would slowly go back to half point. Twice the needle went to the red section. When it did that a message came up saying "Engine temp too high". I cut the car off and the engine fan continued spinning. Even when I took the keys out of the car. I guess that's a safty feature or something.
Anyway, I would like to know all possiblereasons for an overheat. Thermostat's been changed. The fan works, and due to the slow rising and falling of the temp needle I would guess that the sensor is working also. The water pump is covered under my warrentee but I haven't had that checked yet. I would like to know if there is anything else before I take it in. Please help. Thanks for reading.
Anyway, I would like to know all possiblereasons for an overheat. Thermostat's been changed. The fan works, and due to the slow rising and falling of the temp needle I would guess that the sensor is working also. The water pump is covered under my warrentee but I haven't had that checked yet. I would like to know if there is anything else before I take it in. Please help. Thanks for reading.
#2
RE: What are reasons for overheat?????
I'm not familiar with the modern S type,only with my 1965 S type.
the transmission in modern cars has an oil cooler which is sometimes connected to the radiator to cool the fluid.
Has anybody checked the transmission fluid level? A transmission with not enough fluid will overheat the engine.
A clogged radiator is a possibility but on such a young car I doubt it.
a bad Fan Clutch (one which doesn't disengage when the engine is accelerated).
assuming your car has one.
A bad water pump, but then it would leak through the "weep" hole.
Air bubble in the system, you need to "bleed" the system from air.
To check for air bubbles or to bleed/purge air from cooling system:
Loosenradiator cap to first "detente", (make sure it cannot come off)
Heater Temp all the way to Hot,Heater fan in High.
start and warm engine up to temperature, allowing thermostat to cycle through two or three openings and closings to stabilize system,
Watch as the system "regurgitates" any air for around 20 minutes after reaching normal temp.
you might see a rush of coolant come out from under the cap. Any air is now bled.
Close radiator cap tightly with a rag to avoid burning hand.
When theengine is cold again,(next morning), top up the coolant.
Hope this helps a bit.
Jose
the transmission in modern cars has an oil cooler which is sometimes connected to the radiator to cool the fluid.
Has anybody checked the transmission fluid level? A transmission with not enough fluid will overheat the engine.
A clogged radiator is a possibility but on such a young car I doubt it.
a bad Fan Clutch (one which doesn't disengage when the engine is accelerated).
assuming your car has one.
A bad water pump, but then it would leak through the "weep" hole.
Air bubble in the system, you need to "bleed" the system from air.
To check for air bubbles or to bleed/purge air from cooling system:
Loosenradiator cap to first "detente", (make sure it cannot come off)
Heater Temp all the way to Hot,Heater fan in High.
start and warm engine up to temperature, allowing thermostat to cycle through two or three openings and closings to stabilize system,
Watch as the system "regurgitates" any air for around 20 minutes after reaching normal temp.
you might see a rush of coolant come out from under the cap. Any air is now bled.
Close radiator cap tightly with a rag to avoid burning hand.
When theengine is cold again,(next morning), top up the coolant.
Hope this helps a bit.
Jose
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RE: What are reasons for overheat?????
this would help, http://members.aol.com/agspeed/overheating.htm
If the engine overheats, the first thing that will happen is a gasoline engine will start to detonate. The engine will ping and start to lose power under load as the combination of heat and pressure exceed the octane rating of the fuel. Overheating can be caused by anything that decreases the cooling system's ability to absorb, transport and dissipate heat: A low coolant level, a coolant leak (through internal or external leaks), poor heat conductivity inside the engine because of accumulated deposits in the water jackets, a defective thermostat that doesn't open, poor airflow through the radiator, a slipping fan clutch, an inoperative electric cooling fan, a collapsed lower radiator hose, an eroded or loose water pump impeller, or even a defective radiator cap.
- - > The most common problems jaguar xj6/xj40 radiator fall prey to are clogging (both internal and external) and leaks. Dirt, bugs and debris can block air flow through the core and reduce the radiator's ability to dissipate heat. Internal corrosion and an accumulation of deposits can likewise inhibit coolant circulation and reduce cooling. A good way to find clogs is to use an infrared thermometer to "scan" the surface of the radiator for cold spots. If clogged, the radiator should be removed for cleaning or replaced. Backflushing the cooling system and/or using chemical cleaners can remove rust and hard water scale, but may do little to open up a clogged radiator.
If the engine overheats, the first thing that will happen is a gasoline engine will start to detonate. The engine will ping and start to lose power under load as the combination of heat and pressure exceed the octane rating of the fuel. Overheating can be caused by anything that decreases the cooling system's ability to absorb, transport and dissipate heat: A low coolant level, a coolant leak (through internal or external leaks), poor heat conductivity inside the engine because of accumulated deposits in the water jackets, a defective thermostat that doesn't open, poor airflow through the radiator, a slipping fan clutch, an inoperative electric cooling fan, a collapsed lower radiator hose, an eroded or loose water pump impeller, or even a defective radiator cap.
- - > The most common problems jaguar xj6/xj40 radiator fall prey to are clogging (both internal and external) and leaks. Dirt, bugs and debris can block air flow through the core and reduce the radiator's ability to dissipate heat. Internal corrosion and an accumulation of deposits can likewise inhibit coolant circulation and reduce cooling. A good way to find clogs is to use an infrared thermometer to "scan" the surface of the radiator for cold spots. If clogged, the radiator should be removed for cleaning or replaced. Backflushing the cooling system and/or using chemical cleaners can remove rust and hard water scale, but may do little to open up a clogged radiator.
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