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Old 01-14-2009, 05:18 PM   #1
Join Date: Aug 2008
Location: Central Va.
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My 97' TJ Sport's heater doesn't seem to throw out enough heat. Temp gauge reads normal, around 210 or less, and it will drop to around 195, so I would think the thermostat is working.
Could it still be the thermostat or should I be looking at the heater core or possibly the radiator?

Also just replaced the oil pressure switch because my oil pressure would flucuate between 40 and sometimes 0.
Now I have steady pressure at around 42 pounds at idle or when driving.
Does this sound about normal?

Jeep runs good and doesn't use any oil and doesn't smoke. I also just replaced the plugs and they looked normal without any fouling of oil.

Thanks for any suggestions,

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Old 01-14-2009, 06:10 PM   #2
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How many miles are on it? The water pump could be worn bad. I'd flush the sytem, especially the heater core. Take the heater hoses off the engine and flush both sides several times.

'98 Sahara, 35's, Fully Armored?
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Old 01-14-2009, 06:23 PM   #3
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i'm pretty sure my water pump is shot, but so is my p/s. check your fluid levels. i had a leak in my radiator for about a year before the radiator finally exploded and it was bad. before the big blow up my heater would blow cold air when the fluid level was low. now i replaced the radiator but i'm pretty sure the damage was done to the water pump before the blow up.
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Old 01-14-2009, 06:32 PM   #4
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If your radiator fluid is not low then I would try the following.

Clogged heater core. Take the hoses off the core and use a piece of hose that with fit it to your water hose. Hook it up in reverse direction that it normally flows water and turn the water on. If may flow slow or may seem like it is flowing normal. Do it first in reverse direction because if there is trash in it pushing water in the same direction may lodge it in there even worse. Blow backwards first and that usually does it first try. Hook it back up and see if that takes care of it.
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Old 01-14-2009, 07:38 PM   #5
Join Date: Aug 2008
Location: Central Va.
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Thanks for the replys,

It has 112,000 miles and looks like a new radiator (I bought the Jeep used) and new hoses and is full of fluid.

Hope it's not a stupid question but how do I tell which direction the water flows in the core?
It has a smaller hose 5/8" and a larger hose 11/16". Is the smaller hose the inlet and larger the outlet?

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Old 01-14-2009, 07:42 PM   #6
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I don't know, look where the hoses are returning to and you should be able to decipher which is which. Which feeds to where, which is before pump, which is after so on and so forth. Sorry I am having a brain fart right now and not around my jeep to look. Hope that helps

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