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Scoot
New User
Jun 19, 2008, 7:12 PM
Post #1 of 3
(5693 views)
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Jeep Overheating Dilemma
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I have a 2000 Jeep Cherokee with 90,000 miles that began overheating about 3 months ago. It happened after a freeway drive of about an hour up in the mountains on some twisty roads. Luckily the trouble began AFTER I was off the mountain!
I took it to one mechanic who looked at it for two seconds and said, "new radiator." I felt suspicious as this shop is known for unneeded repairs, so I went to another guy. This guy kept the car for a couple days, running all kinds of tests. No radiator problem, no leaky hoses. And he could NOT get the thing to overheat. He ended up doing a flush and adding some fluids, but basically said - "I can't see a problem with this car."
I then continued driving it with no problems. But I only drive it about 3 miles to and from work, so it's hard to tell. I've taken a few weekend trips since then without incident - some up to 2 hours away. No problems. But every once in awhile, lately, I'll get a little scent of water mixed with engine - the smell you get when a car overheats. Just a hint, though, and no actual overheating.
Well, today I headed up to the mountains again, and whammo. Same exact overheating problem returns.
Is it something caused by elevation (this mountain is about 4000 feet, and I'm usually at sea level.) Or is it the strain on the engine going uphill? (It's a twisty road, but well graded and navigable at 40 - 55 mph.
By the way, both times when the car overheated, it SUDDENLY shot up into the red zone, then just as suddenly went back to normal. Then....drive some more - Bang! it goes back up....then back down. Very weird. Almost as if it reaches a certain point and the flow is suddenly cut off or being splashed over the engine. (LOTS of steam.)
Any advice is much appreciated....
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Jun 20, 2008, 7:17 AM
Post #2 of 3
(5682 views)
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Re: Jeep Overheating Dilemma
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A few things come to mind with altitude: There's a lot less air in the air to cool your radiator! Any uphill grade is a lot of load on the engine - load=heat.
Caloric value of water vs anti-freeze. Water wins big time for exchanging heat over anti-freeze -- lowering concentration with extremes helps but needs changing more often. Concentrations over 50% cause problems! Stronger is NOT better at all!
Pressure cap. Boilding points are seriously lower with less pressure. Water = 212F at sea level which is under 14.7 psi without knowing it. Properly working 15lb pressure cap adds 45F to temp before boiling and boiling liquids don't exchange heat for diddle.
Fan clutches: They lose about 10-15% of pulling power per year! Toss an old one for a quality thermostatic new one.
Those are the items that need to be perfect for higher altitude performance of cooling systems,
T
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jeep driver
Novice
Jun 26, 2008, 3:10 AM
Post #3 of 3
(5667 views)
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Re: Jeep Overheating Dilemma
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you can also upgrade to an electric fan instead of the clutch fan witch will work better without pulling power from your engine so therefore you gain cooler running temp and gain horsepower, which is always a plus!!!!! you can buy an awesome upgrade kit which will replace the electric and clutch fans for three electric fans. for around 300.00 on ebay. I bought one for my 1995 jeep cherokee with 313,000 miles on it. it is well worth the money. also you can upgrade the thermostat for a lower temp. thats about a 6.00 fix!!!!!
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