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      Sean T. is the new TSOC President!   03/27/16

      As some of you may know, I started this forum back in 2010 in response to TCCA being sold to AutoGuide. I originally made this forum and called it the Taurus Club of Michigan (or something like that) purely as a joke, except a bunch of members from TCCA started joining. We eventually changed the name to the Taurus and Sable Owners Club, and we instantly started getting tons of signups from TCCA members in search of a new forum to join.  I only had my Taurus for about 6 months, and have moved on to the Mopar side. After 6 years, it seems weird for me to be president of TSOC. So as of today, I am 'stepping down' as President of the club and hereby hand the title of TSOC President to Sean T! I would say that most of you already know who he is, and I think he will do a great job as TSOC President. I will remain an admin of the forum and will continue to manage the server and forum software. Sean will be taking over all other responsibilities, including being in charge of the TSOC donations and money management. I will continue to pay for domain renewals, forum license renewals, and any other forum expenses, with Seans approval. Everybody please welcome Sean as the new President! Click here to view the full thread. ->
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      Having trouble logging in after the update?   04/25/16

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-chart-

Radiator Cap Fail

9 posts in this topic

Some warnings and some info on radiator caps.

Since I had a failure on my ’02 Lin Cont, and replaced it, and took the old one apart, I have some first hand ifno.

Two U-Tube plays, but much is bogus. Failure has nothing to do with what the cap is used on.

The little spring does not set the popoff pressure like 16#. It is the big spring in the top.

The little spring lets air in to prevent hose collapse when it gets cold, and resets the starting pressure to near zero cold.

The little very soft spring in the bottom is OK but it sometimes fails to reseal. When that happens, you have same as no radiator cap. You loose coolant, as I did. Fortunately I was close to home and limped home without overheat. Also fortunate, the Lin has low coolant warning. No steam, no sign of coolant loss for me.

My cap checked just fine on the tester, but still did not seal on the car. My op is, the quick pressure up of the tester seated the small valve, but on the car, slow pressure did not seat it and no pressure was had.

So, a failure can happen on any Ford product, as the same cap was used from ’92 to present on nearly all US made products. Ford changed the part and it’s number at the dealers.

As for me, I will not trust aftermarket, or possible aftermarket of old stock Ford parts. Dealer charged me $10 so it is minor, and I got the new stock for sure. Does not look like the OE part.

 

 

-chart-

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The small spring getting weak/failing on the vent valve happens on many brands from my experience. Simple check, if it doesn't snap shut, it's bad.

Big spring rarely fails.

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The small spring getting weak/failing on the vent valve happens on many brands from my experience. Simple check, if it doesn't snap shut, it's bad.

Big spring rarely fails.

The springs are made of SS and likely never weaken. The rubber gasket on the air intake side (light spring) likely ages and fails to seat. it opens many times over the age of the vehicle. The big spring and it's rubber seat likely never open over the life of the car. Only in a overheat case, or if the tank is overfilled.

I still have two vehicles with more miles with factory caps.

As to the guy testing all the failed truck caps, I would like to see him test a new cap and see if his tester works. The fellow who tested my Lin cap and my Sable cap saw the same thing "good" , at least within the acceptable range. (the range is #14-18#) Neither leaked off in the short testing time. The Lin cap on the Lin simply did not generate any pressure, as I squeezed the hose when hot and it was limp. The Sable cap built pressure and easy to feel good pressure.

The cap must be able to hold pressure over many hours with absolutely no seapage.

Well to remember, the control engine temp is one thing, but down where the heat is, it hotter and likely boils some even under pressure, but that is within the design. No pressure and you will get a steam pocket and overheat.

Just my take.

Once burned, twice shy.

Keep cool.

-chart-

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Chart said:

"The rubber gasket on the air intake side (light spring) likely ages and fails to seat"

I've always kept a healthy supply of radiator caps in the inventory because we seem to go thru them a lot on the buses.

One of the mechanics finally asked why I don't just keep a supply of the gasket because that's what fails !

So I reduced the number of new caps, added the gaskets, and voila.. everyone is happy and I'm saving a bit of inventory costs.

I just love it when a mechanic says "come here, let me show you something".... it means I'm about to learn something new about engines !

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Chart said:

"The rubber gasket on the air intake side (light spring) likely ages and fails to seat"

I've always kept a healthy supply of radiator caps in the inventory because we seem to go thru them a lot on the buses.

One of the mechanics finally asked why I don't just keep a supply of the gasket because that's what fails !

So I reduced the number of new caps, added the gaskets, and voila.. everyone is happy and I'm saving a bit of inventory costs.

I just love it when a mechanic says "come here, let me show you something".... it means I'm about to learn something new about engines !

Information is a good thing. Remembering it is quite another. Now, where were?

Oh yes.

There are two issues here.

The gasket from the cap to the top of the tank can leak, even ever so slightly and be a problem. Testers do not test that.

As what I saw, they just test the over pressure setting. That overpressure should never happen in normal use.

Ok, the other is the rubber gasket on the light spring air intake, or no vacuum system. That is part of the cap and cannot be changed. If it fails to seat completely, then the slow rise of pressure from coolant expansion, then you have no pressure. The light spring holds the gasket lightly and may not seat it when it gets old.

Problem is, in my view, you can't easily test it. Testing does not duplicate what the car does. RockAuto gets ~$5 for Motorcraft cap. Half that if you want to trust aftermarket parts.

And on the car, it works today, works tomorrow, then it fails the next day and it is a real high risk to your vehicle. I was fortunate to get a warning.

I have good reason to think this one has failed before, and cost someone lots of $$$ for a bad diag. I had the FEAR of head gasket failure, before getting some common sense and tried the cap off the Sable.

And while on my soapbox. Lincoln is pathetic on the coolant tank. Taurus/Sable is thoughful. Cold fill lines, and you can check in a few seconds.

The Lin you have to cold take the cap off and measure 70mm. DUMB! ( or is it 60mm?) Still DUMB.

Have a nice winter. Snowed here, this am. wet heavy, snow blower did not like it. My new shovel did like it. Just got a new one yesterday.

-chart-

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Replaced the caps on both the 97 and the 00. The temperature gauge on the 00 doesn't go as high up anymore.

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Been in the JY today, up and down every Ford row, looking for a seat and headlamp.

OK my observation as I went.

Many, if not most rad caps missing.

Wonder, why would anyone buy a used one from the JY.

Imporoved design at Rockauto is $5.68 and it is the NEW design, not the failing OEM design.

Also, so many Taurus/Sables with the coolant tank gone. I am sure they have crack issues BUT:

How many times is a bad rad cap mis-dag as a bad tank?

I do not believe a bad cap can be tested. Based on my exp only. I had a friend test mine and it tested fine. I watched it test. But put it on the lin, warm it up and coolant all over the place. New revised cap from Ford, ~$11 including tax.

Just my take.

My rant.

Sharing here.

-chart-

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I am having over heating problems on my 2007 Ford Taurus SE. When my my car is running it wants to overheat. I replaced the thermostat, still the same problem. Checked the fans, no problem there. The radiator cap seems to work fine also. I really don't know what else to look at and replace in order to keep it from overheating.

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The coolant degasser bottle caps on these cars (and all Ford products from the same era) are known to fail. Visually they look fine. The problem is the spring inside loses its temper and can't hold the proper pressure in the cooling system. Did you check the system pressure with a gauge while hot? A replacement cap with a better spring is only ~$5 at Advance (should be similarly priced at other retailers.) I would try replacing the cap first. If that doesn't fix it I would look at the water pump next as the impeller blades are known to rust away if the coolant isn't changed regularly (assuming you have the Vulcan, which you should for your trim level.)

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