I have a 1995 Ford Windstar, 3.8L with 170k miles. This vehicle has a coolant habit I have not been able to figure out. It goes through about a quart of coolant every 3-4 weeks, and any time the van is driven or even left to idle for a few minutes, you can smell coolant all around the vehicle, strongest near the engine compartment. There is no steam or excessive smoke from the tailpipe, the engine runs smooth as silk, has plenty of power, does not run hot, has no oil contamination, no play in the water pump impeller shaft, and there is no evidence of external leaks. A pressure test shows a loss of 2lbs of pressure over a ten minute period, and with the engine running with the pressure tester on the vehicle, system pressure will rise 8-10lbs within 3-4 minutes. I know such a rise in pressure can indicate a head gasket issue, but is this a significant and rapid enough increase in pressure to indicate something like that? The cooling system in this vehicle is tight enough that less than three strokes of the pressure tester will put you at 16lbs of pressure. What else is there that can make my coolant disappear and taunt me with its smell, but be seemingly impossible to find?
Two TSBs Apply To A 95 Windstar Losing Coolant.
Some 95 & 96 Windstars only develop leaks at the seals in the radiator between the core and end tanks at ambient temperatures below freezing.
Some Lincoln Continental 88 - 94, Mercury Sable 88 - 95, and Ford 88 - 95 Taurus & 95 Winstar
only with the 3.8L:
“Coolant may leak from the head gaskets and/or the vehicle may overheat. There may also be concerns of reduced heater output due to low coolant levels. This may be caused by insufficent sealing of the head gaskets.”
Revised head gaskets and bolts are supposed to improve sealing and clamping force.
CSA
You may need to have someone put a dye into your coolant to find the leak, although the dye that is already in it usually shows up a leak after awhile. The newer “universal” coolants seem to be better at that than the older “green” stuff. A UV dye is easier to detect with a black light and will spot the leak immediately, unlike regular dyes that may take awhile to leave build up the requisite residue.
BTW, the pressure test doesn’t include testing the cap, a new cap would not hurt, but I don’t think that it is the cause of your leak.
I found the leak. It was leaking out the lower intake gasket on the backside of the engine, in much the same way the GM 2.8/3.1/3.4 engines do. I never thought to look there, but when the engine is running, with a flashlight shining on the source of the leak, you can see a thin stream of coolant start to trickle through the gasket, down the head and bellhousing. I might just tackle this project this weekend, along with the driver’s side wheel bearing that’s been growling at me lately.