Engine cooling system question

ford
taurus

#1

I have a 98 Ford taurus 3.0 V-6 engine. The car’s cooling system has an overflow jug which is where you put in the antifreeze when needed as you do not have direct access to the radiator. From that overflow jug there are 3 hoses I can see coming from it. One is about the size of your thumb and is on the bottom facing the radiator and looks to be the hose that directly feeds the antifreeze right into the radiator. There are then two small hoses that come to the overflow jug. One of the hoses is on the back side and it contects into a piece of pipe that then runs along the top of the engine, the other is above the hose that goes into the radiator and it contects into a pipe that runs down through the headlight casing and into another pipe. Both of these hoses are at the top of the overflow jug. So what do these two hoses do? Also I am dealing with a bad headgasket issue and have been getting antifreeze out via the overflow jug since I had the car, but now the amount is increasing, but now leaking out underneath the overflow jug.


#2

The overflow jug is actually called the surge tank. The entire system including the surge tank are under pressure once the engine and cooling system are warmed up. The tank is the highest point in the cooling system. The lower hose maintains fluid balance and the two upper hoses maintain vapor (air) balance. On a healthy engine, fluid level in the surge tank means plenty of fluid in the engine.

However, yours is not healthy. A bad head gasket allowing combustion gasses into the cooling system overcharges the cooling system with pressure. The surge tank cap should be calibrated to release this pressure, but may not be able to handle the volume of gas for the head gasket breach. This forces the system to handle too much pressure, and is stressing the tank, radiator, hoses, and other coolant seals.

Continuing to drive the car will keep spreading the damage.


#3

The cap on mine is just a twist on type, you just twist it on till you hear the clicks and then stop from what I was told. What baffles me is that the fluid I am losing now is coming from under this surge tank, where before it was coming from around where those smaller hoses connected to the surge tank. I am wondering since I have gone to more water vs. antifreeze if that is not causing more additional fluid to be lost, or it is just the degeneration of the headgasket issue.


#4

Taurus surge tanks are notorious for cracking and leaking. In fact I have seen an incorrect diagnosis of a bad head gasket when the whole problem was a cracked surge tank. Your '98 Taurus surge tank is available from any good auto supply store. I think the last one I bought was about $35. Get a new pressure cap too, if it isn’t included.


#5

How difficult is it to remove and replace? Can an idiot like myself do this or should i just buy the part and take it to my local mechanic to have him replace it?


#6

I suspect that you can handle it.


#7

From looking at it and doing some google searching, it appears to be held on with 3 bolts, but that one of the bolts is very difficult to remove due to location.