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Tim Mohr
Tim Mohr, ASE MASTER TECH
Category: Ford
Satisfied Customers: 15121
Experience:  30 YRS EXPERIENCE, FOREIGN AND DOMESTIC, GAS AND DEISEL
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WHY DOES COOLANT LEAK FROM 1999 FORD EXPEDITION

Customer Question

WHY DOES COOLANT LEAK FROM 1999 FORD EXPEDITION
Submitted: 7 years ago.
Category: Ford
Expert:  Tim Mohr replied 7 years ago.
Hi, my name is XXXXX XXXXX area of the engine compartment is the leak coming from?
Customer: replied 7 years ago.
RESOVIOR
Expert:  Tim Mohr replied 7 years ago.
the coolant is coming out of the resevoir? if it is, then suspect the head gasket is bad, does the gauge run hot?
Customer: replied 7 years ago.
i HAVE HAD A CERTIFIED MECHANIC LOOK AT MY TRUCK, HE RAN A PRESSURE TEST TOLD ME NO GHEAD GASKET LEAK, JUST TOOK ON AN 800 MILE TRIP RUNS GREAT, THE TEMP GAUGE WILL GO TO HOT FOR A FEW SECONDS THAN BACK TO NORMAL, THIS PROBLEM DID NOT START UNTIL A NEW WATER PUMP WAS INSTALLED, CHANGE THE TERMOSTAT 6 TIMES
Customer: replied 7 years ago.
have you come up with anything
Expert:  Tim Mohr replied 7 years ago.

so this happend after waterpump replacement?

Customer: replied 7 years ago.
yesreplaceed in April then again with a new one this past Sat, the mechanic thought maybe the water pump was defected still having same problem coolant leak all out on to outside of truck
Expert:  Tim Mohr replied 7 years ago.
This is still leading to bad head gasket, you need to do a simple chemical test to determinr this, you can get the test kit at most autoparts stores, and it is very accurate and can find miniscual exhaust gases in the system,if it is blowing out the recovery bottle, then you are some how pressurizing the system, which is almost always abad gasket,Tim
Customer: replied 7 years ago.
had a pressure test done, the mechanic said all was good NO HEAD Gasket problem, he had the truck for 8 hours testing and can not come up with anything.
Expert:  Tim Mohr replied 7 years ago.
A pressure test will not determine a head gasket leak, a cylinder leak down test, or a chemical test must be done, pressure test will only test for external leaks, not an internal head gasket leak,Tim
Customer: replied 7 years ago.
he ran the test with chemical
Expert:  Tim Mohr replied 7 years ago.
what is the pressure building to in the system when it comes out the resevoir?
Customer: replied 7 years ago.
how do I determine this, as the truck run greats while driving, just leaks coolant out of the reservoir
Expert:  Tim Mohr replied 7 years ago.
you must put a pressure tester on it and run it, then how high the pressure is getting, does it blow out the resevoir with out it overheating?
Customer: replied 7 years ago.
yes blows h=out while not registering hot
Expert:  Tim Mohr replied 7 years ago.
there is only 2 ways for pressure to build in the system, one is overheating, and you say it blows without overheating, and the other is exhaust gasses entering the system, there is no other way to build pressure in the cooling system, so its either a bad head gasket or a cracked head, Tim
Customer: replied 7 years ago.
but if it a bad head gskt or crack head, how does it still run so good like i said just took 800 mile trip with no getting hot probles just coolant leaking
Expert:  Tim Mohr replied 7 years ago.
because the leak is not big enough to put coolant into the motor, but even a small leak will pressurize the system,Tim
Customer: replied 7 years ago.
someone said that if a blow gasket the oil would be mucking and it is not is the correct
Expert:  Tim Mohr replied 7 years ago.
not always, if the leak is small enough it wont, but it will pressurize the system, like i said earlier, there are only 2 ways for the system to get pressurized, one is heat and the other is from exhaust gasses entering the system, there is no other way,Tim
Tim Mohr and 3 other Ford Specialists are ready to help you
Customer: replied 7 years ago.
Thanks for your help
Expert:  Tim Mohr replied 7 years ago.
anytime my riend, let me know,Tim

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