99 Coolant Problems - Please Help

[retrohwam]

I have a 99 Sable that I'm experiencing a problem with that I need some help with. About 3-4 months ago I relpaced the coolant reservoir with an after market product. It was cracked and I figured it was just time. Since then I've been having a problem with the coolant "boiling over" and coming out the resevoir cap after the car has been shut off. The problem was intermittent at first but seems to be happening on a daily basis now. The last two mornings on the way to work - 10 miles - mostly 40+mpg driving - it has happened. Last night on the way home (much warmer, I live in Mississippi) I didn't have a problem. On a recent trip I stopped after about 60 miles and it happened - added H2O and didn't happen again. Replaced the thermostat less then 2-weeks ago. It's been about 1.5 years since complete flush was done by a service tech.

BTW - this auto has always had coolant that looks like it came out of a mud puddle. Thinking about replacing the water pump this weekend, but wanted to get a feel if I heading in the right direction.

Any help would be appreciated,
Duane

[brokenantimatter]

Dpes your after market resivoir have the same volume capacity as your factory part and is your resivoir filled correctly? If the answer is yes I would look into replacing the thermostat and have the radiator flushed.

[shorod]

Make sure the cooling fan is working. Normally, if the engine is hot, the cooling fan will continue to run even after you remove the key until the engine cools. Were you running the A/C the past couple of days when the coolant boiled over? The A/C and defrost should also cause the cooling fan to run.

Also, check the oil on the dipstick. Does it look like oil, or like chocolate milk?

-Rod

[Huney1]

I doubt the new reservoir is the same and you can get one for a Taurus at a salvage yard. Before I went to a lot of trouble I'd try that, replace the new one with a real Tarus tank and 16 lb cap in good condition. The coolant should be the color of the anti freze but not muddy and that calls for a cooling system and heater core flush. Overheating is the number one cause of blown head gaskets so get it fixed pronto. Boil over: You must have a 16 lb reservoir cap or the cooling system will not work the way Ford designed it. http://www.aa1car.com/library/overheat.htm

[retrohwam]

Thanks for your replies - to answer a couple of questions.
The new tank visually is identical to the old one with a cap that has 16psi
on top of it - I'll try running it with the cap from the old tank.

Oil looks good - I'm kinda anal when it comes to changing it out every 3k

Have been running the ac - haven't noticed if the fan continues to run
after shutting it down - I'll pay particular attention to that next time it
happens.

This morning on the way to work I had no problem.

Thanks again,
Duane

[Huney1]

Duane, all things considered, if the new tank is same as the old and it's boiling then it sounds like the pressure cap is bad because for every one pound of pressure you put on it it raises the boiling point three degrees. Boiling point 212F with 16 lb cap X 3 = 48, so 212 + 48 = 260F would be your boiling point, so if that sucker is boiling & steaming over it is very, very hot! DUH? That is, *IF* the cap is good and if not it's easy to understand why it boils. New caps not all that expensive and available at most auto parts stores. Heck of a lot cheaper than replacing blown gasket(s)! Let's take it one step at the time and I beleive we can solve your problem. However, a cooling system flush to get rid of the mud is an absolute must, and I mean like pronto. And while you're at it, I believe it would be a good idea to replace the thermostat with a HIGH QUALITY 'stat, not an el-cheapo. http://www.stant.com/ Most parts stores have 'em and you want the one that looks like this: http://www.saleshound.com/saleshound...ailerID=-99798

NOT the one that has a butterfly wing. OK, always glad to oblige, hope this helps and let us know how goes it.

[mwt878991]

The pressure cap is bad.

I bought one of the aftermarket (Chinese) units for my kids 99

A few days after it did the same thing.

I saved the original tank cause it wasnt broken ( I just had the brown coolant problem) and put the OEM cap back on it and havent had an issue since.


Mike

[Huney1]

"The pressure cap is bad." Good deal and glad you solved the problem. Now a good system flush and you'll be good to go for summer driving.

It's been said many times before; "The cooling system is one of the most important and most neglected components of an engine." The right way is get a new cap every few years because they don't cost that much.
Have a nice week end and enjoy your Taurus.

[retrohwam]

Eureka!

How could something so simple be so aggravating? Funny thing is that the first tank shipped to me was broken so they shipped me a second and both of those “new” caps had failed. Got a new one this weekend and problem appears to be solved.

A fortunate side note – while my system was being flushed this weekend the metal “T” on the back side of the heater bypass failed and needed to be replaced. Can’t think of a better place for it to fail

Thanks for all your help.
Duane

[brokenantimatter]

Next time spend the extra $60 and get the OEM.