Testing for bad head gasket

The saga of the overheating Taurus continues. Someone I respect referred me to a shop & mechanic. He quoted me some good prices for water pump replacement and radiator replacement so I don't think he'll rip me off like
that. But...
He stated that he would do a full diagnosis of the cooling system to try and determine the cause before just replacing parts to see what works. Part of that includes testing the air in the coolant reservoir for the presence of hydrocarbons - he says that if there's an elevated level of hydrocarbons in the coolant tank that this would indicate a blown head gasket. Does this sound right? Is he just blowing hydrocarbons up my a** so he can make a lot of money off of me?
Here are my symptoms again: In stop and go traffic the car starts to overheat (this was intermittent for a while but now happens regularly). On interstate the temperature is about normal but heats up rapidly when I hit the exit ramp and slow down to 25 MPH or pull into the rest area. Some said thermistat so I replaced that - no help. Some said clean and flush cooling system and add fresh coolant - did that (it was time anyway) and no help. Here's some things I've noticed - 1) upper radiator hose from thermistat to radiator is hot and pressurized at normal or elevated operating temp 2) according to one mechanic the lower radiator hose from radiator to water pump seems significantly cooler than it should be (I can't reach it) at normal or elevated operating temp. This suggests restricted flow through the radiator. 3) heater return (bypass) hose is hot near water pump but cools rapidly as it approaches the firewall 4) if I turn on the heater after the car warms up it starts blowing warm air, but usually cools down to approximately 80 degrees within about 2-3 minutes - the faster the car is moving the faster it cools off. If I turn off heater and adjust temp back to low for a while, then turn heater back on and adjust temp to high, it starts blowing warm air and cools rapidly again. 5) this car uses 2 electric fans on radiator and both "appear" to be functioning normally.
There was a TSB published in 1998 pertaining to this problem with the recommendation to install a new coolant bypass kit (to keep the problem from recurring) in addition to flushing the system and replacing the fuel pump if necessary. The "Backyard Mechanic" posted the following link in another thread showing a bad water pump on a comparable car to mine: http://blizzard.zmm.com/waterpump /.
Thanks again for everyones' help,
Phil
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Phil Nospam wrote:

Good idea. I'm convinced it's the pump,but since he hasn't been involved with the car he would be remiss if he didn't do a proper diagnosis.

It's a simple test and part of proper diag. The 3.0 is a tough motor, but you never know. Although very uncommon with this motor, head gaskets are a possibility. The tester resembles a turkey baster filled with blue fluid. He'll draw the "fumes" out of the degas bottle and if there is C02 in the gas the fluid will turn yellow.

restrictor. You may want to do that along with the pump. The kit is available from the dealer.

Good luck.
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id be thinking thermostat and maybe water pump impellers worn off . not to expensive to check.
http://www.minibite.com/america/malone.htm
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