Long story - the bypass, and the heater core.
Hi, I'm a new member (Canada - Eastern Ontario)
Own a 2000 Taurus SE sedan - 3.0 L V6 Vulcan Engine. Over 200,000 km now.
I read with much interest all the the heater core / cooling system issues that everyone is writing about.
I too have had some of these issues. Long story - but I'll try and fit it in.
1. 5 years or more ago started to develop a slow drip coolant leak from the front engine cover. Too small a leak to worry about for about the next year and a half / two years - but the leak got worse. Plus, it was leaking down on a hot exhaust part (cat convertor?) and then vapourizing / steaming up into the engine compartment - and then could smell in car - being taken into the vent system. Worse at a stop light. Not good. Not healthy. Gross smell. Had to fix at that point. Plus loosing too much coolant. Bad for the environment. Expensive.
2. Maybe 4 years ago, tried a stop leak product in the coolant. Helped slow the leak for awhile, maybe a year, but had other serious consequences. ( ex. Ended up plugging up the heater core - and then no heat in winter - added expense and trouble to have system flushed. )
[ SO I DO NOT RECOMMEND EVER USING A STOP LEAK PRODUCT IN YOUR COOLING SYSTEM - There are too many consequences and trouble later on. Don't do it. Plan to fix the problem correctly - without using any stop leak product. ]
3. Eventually had to have the Engine, front cover gasket replaced since it was leaking too much coolant. That was expensive and took some time at the shop. I had them replace the water pump and front crank seal (?) at the same time - it just made sense to do that at the same time since all those parts are off and accessible at that time. So new water pump - for sure.
In order to do this work, the oil pan had to come down - so they tell me. So they needed a new oil pan gasket also. That is some kind of special rubber gasket from Ford - so it was expensive. More than a hundred bucks just for the special oil pan gasket.
4. The use of Stop Leak in the coolant back when, eventually plugged up/restricted the heater core. No heat in winter. So a couple years ago, took it to a Cooling system and Rad specialty shop. They Flushed the system and did a special Heater Core Flush separately - and that brought back all the heat. Great.
BUT ... The RAD SHOP also cut the short little heater core BYPASS hose, that runs between the black steel pipes on the firewall, and plugged the two short ends with short 1/2 inch bolts - cut short, inserted as plugs, and hose clamps to seal.
So the RAD SHOP blocked my heater core bypass tube completely on me.
Great - that got more hot coolant to flow through the heater core - but had other consequences later on.
[ SO - I DO *NOT* RECOMMEND YOU PERMANENTLY BLOCK YOUR HEATER CORE BYPASS TUBE / HOSE - RE: MY PRACTICAL EXPERIENCE - PLEASE READ ON ]
5. Summer comes, and when things get HOT, I notice my temperature guage on the dash is fluctuating up and down alot. From mid position to up near the hot mark. Never did that before. Plus the electric rad fans are cycling on and off a LOT more than normal.
I investigate, find the bypass plugs installed by the rad shop, and remove them, and replace them myself with a short piece of 1/2 copper tube.
Things go back to normal and work as before. No guage fluctuation. No rad fans cycling alot.
6. Few months later, I replace, and extend the bypass hoses upwards to the upper firewall area, where they can be easily accessed. The hoses come up in a curved loop fashion and I installed an EVERCO heater control valve in the bypass circuit. Controlled manually from the cabin with a choke pull off cable. Not easy - but I did it.
7. Couple years later - now - lack of heat again in the cabin.
So I go to a garage, explain the issue, and he does a system flush for me - but we decide to not do a separate heater core flush yet. Just do a simple system flush (without heater core flush for now). Installs a new thermostat at the same time. Fine.
No luck. Still only about half the heat I should have in the car. And winter is coming on in Canada. Need full heat to de-ice / defrost the car.
So I did the Heater Core flush myself after at home. And that gave me full heat again.
Read on ...
8. Did Heater Core Flush myself at home.
Since last year, I already had extended the bypass hose connections up to the top of the engine compartment - I now have easy access to them.
Disconnect the EVERCO heater control valve I installed- gain access to the two 5/8 hoses I installed. Put in two garden hose fittings / nipples and clamp.
Using 2 pair of vice grip, slip over the jaws, some short pieces of extra hose to protect, and clamp off / plug by squeezing - the lines from the water pump to the heater core, and the one from the heater core back to the engine / thermostat.
The heater core is now isolated from the rest of the cooling system - so you can flush it independently.
Flush, first in backwards direction, through one heater core bypass lines access point, with garden hose connected to hot water from inside house.
On first flush, out blows rust, sludge, and couple gallons of brown filty coolant (and that is *after* the garage system flush !) No wonder no heat.
So there was definitely a sludged up restriction there.
Flush a few times back and forth. Out comes more brown stuff and rust particles.
Introduce a safe rad cleaner product into heater core only - Kleen Flo rad cleaner and flush, cut with warm water to make maybe half a gallon's worth - with a funnel elevated into one of the hoses - and out the other hose into container. Let sit for awhile - as instructed.
Re-flush back and forth a few times with warm water.
Final flush with cold water - let the cool water run thru the core for a couple minutes till it looks clear enough.
Re-fill heater core with 50/50 water and new coolant - same method - funnel into one of the bypass hoses - displace liquid out the other into bucket - till you see green coolant coming out.
Close everything up, put everything together, remove the vice grips hose squeezers.
[ Be very careful - don't recommend using harsh cleaner products. CLR I tested pure - eats zinc coating off galvanized nails. Not to hard on aluminum or copper - but did oxidize them a little. I think best to try a safe and recommended coolant system cleaner product FIRST. Don't recommend DRANO. There's steel pipes on the firewall. ]
9. Got an anti-rust spray product in a can and sprayed those steel coolant system pipes on the firewall. The ones everyone says rust out and leak. To slow down rusting from the outside.
SO I'M FLUSHING FROM THE BYPASS TUBES POINTS, AND CLAMPING OFF THE HOSES TO AND FROM THE ENGINE TO ISOLATE THE HEATER CORE.
THAT MADE THE JOB FAIRLY EASY FOR ME. LESS TO DISCONNECT AND RECONNECT. BUT STILL A MESSY AND TIME CONSUMING JOB TO DO AT HOME YOURSELF.
FOR MOST PEOPLE - RECOMMEND TAKE IT TO A SHOP - AND MAKE SURE THEY DO A SEPARATE HEATER CORE FLUSH IN ADDITION TO A FULL SYSTEM FLUSH. EVERY TWO YEARS. THAT WILL SAVE YOU LOTS OF TROUBLE AND PROBLEMS IN THE FUTURE.
I RECOMMEND - MAKE SURE THEY DO *NOT* PERMANANENTLY PLUG YOUR HEATER CORE BYPASS PASSAGE. I FEEL QUITE CONFIDENT THAT BYPASS PASSAGE SERVES AN IMPORTANT FUNCTION. I HAVE PROVEN THAT PRACTICALLY FOR MYSELF.