overheating

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Apr 5, 2005 | 09:07 PM

exracer

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overheating

1993 aerostar 3 lt engine.....new tune up...rad is fairly new and new prestone and on 3rd new thermostat....problem just started recently.....run around town and backroads up to 60k and runs great..anything over that and temp climbs slowly till nearly peged..back off speed and temp comes back down to N in normal....timing is pefect at idle....any ideas ?....

Apr 6, 2005 | 03:18 AM

rlmdad

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From: Corpus Christi, Tx. 78418

Sounds like you might not have gotten all the air out of the system when you last replaced the antifreeze. Also, since the radiator is fairly new, check the upper and lower hoses to see if they may not be collapsing. The final thing to check would be the water pump.

Just my 2cents.

Ron

Apr 6, 2005 | 05:42 PM

copper_90680

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From: Southern California

I think Ron is right about the lower hose collapsing at high engine speed. The lower radiator hose usually has a metal spring inserted inside to prevent just that. However, a lot of times, a new replacement hose doesn't have that, and I normally had to remove the old spring to put it inside the new hose.

During city driving, the suction on the lower hose is probably not too bad, but I suspect that you have pretty good suction at highway speed. When this happens, you not only are choking off the flow, you are also cavitating at the impeller, which is not good.

Apr 6, 2005 | 08:37 PM

exracer

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water pump was replaced last summer....hoses were replaced same time and never had this problem till last week....i will check bottom hose tomorrow....also have drain and flushed system 2times in last 4 days....ran a rad cleaner in it just to be sure rad is clean.....made no difference....wonder if maybe computer is advancing timing to much????

Last edited by exracer; Apr 6, 2005 at 08:40 PM.

Apr 7, 2005 | 05:26 AM

rlmdad

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From: Corpus Christi, Tx. 78418

exracer,

I'd still check the lower radiator hose. BTW, is the radiator the original..could be it's blocked off just enough to work fine at lower speeds but not at higher, can't handle the flow rate at higher speeds...Had a friend who bought an SUV used. Worked fine in daily driving on city streets but he continued to overheat whenever he went on the freeway for anything over an hour. After flushing the system four times, replacing the thermostat, upper and lower hoses, and, even, the heater core...finally removed the radiator and had it tested. It was clogged on almost every other fin, had it cored and resealed, reinstalled..no more problems.

Just a thought.

Ron

Apr 7, 2005 | 08:14 PM

roree

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From: staten island

did you replace the fan clutch?

Apr 11, 2005 | 08:15 PM

exracer

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ok..its fixed.....rad was about 14 months old.....I went back to rad shop again and asked they pull it apart as I felt it was plugged......and it was under warrenty.....if clean it was going to cost me to send it back to get resealed....anyways guess what...over half the tubes were crimped and almost plugged and the rest were full size and clean.2 were never open..a factory defect for sure,,,,very poor workmanship and no quality control .....new rad installed and runs perfect