hey guys, first time here.
I searched the last 20 pages and found lots of coolant problems but not quite like mine. The other day driving home from work I exit the freeway to get gas. As I'm paying at the island I notice coolant puking down my drivers side, near the front wheel. I also heard a hissing sound. From what I recall I don't remember my temps being high. I open the hood and the coolant is leaking from my reservoir cap (the hissing was also coming from there). As I looked at it, the reservoir was full to the max on the cap side and the other half was normal level? I filled the truck w/ gas and the coolant leak subsided. I started the truck and the temp gauge was normal and the engine sounded good. I drove it home watching the gauges like a hawk and nothing out of the ordinary. When I got home it wasn't puking and everything looked good. I did find out the reservoir tank is divided? I have never had this happen and I drove the truck today and everything is great. Even the coolant level looks good after loosing some.

Now here's the wierd part. Earlier that day I cleaned my engine for the first time ever. I first squirted a industrial soap/degreaser on the motor then took a hose and squirted her down. Do you think some soap got in the reservoir and caused this coolant issue? or is this Murphy's law. I also was wondering if I have a potential problem, is this serious, or just one of those things that happen every once in a while?
I have a 2000 F-150 w/ 5.4L, and had the radiator changed out for the recall about a year ago.
Sorry about being long winded but figured the more info you have easier it may be to diagnose.

 

Hello RAS03, welcome. I hope you have some aftermarket gauges in your truck because the factory gauges are grossly inaccurate. It is possible that you may be overheating without the factory gauge indicating so.

I've never had any kind of coolant loss and I dont think it's normal. I would replace the thermostat right away because it is suspect, and because it is cheap and easy to replace.

Good luck and let us know how it turns out for you.

 

Blown head gasket...with engine cold (over night) one person starts engine and shuts off immediately...second person slowly removes the radiator cap and listens for a pressure build-up (interconnection of cylinder pressure to water jacket). Check the oil for coolant mix.
or
Stuck thermostat...test in a pan of water on the range w/thermometer
or
Collapsing lower radiator hose...is it really soft when you squeeze it? (I hear more posts coming!)
or
Funky radiator cap

 

Thank you Le Pew & 52. Area 52, I did check my oil (w/ the dipstick) when I got home that day. It was in perfect condition, or is there a better way to check the oil color? I will check the firmness of the lower hose tomorrow morning. Now for the newbie question, where is the T-stat located? Is there a proper way of removing it and installing it back on? I did notice that the cap for the puke (overflow) tank had a little spring and valve type thing on it. Also, why is the overflow tank divided? It looked like the overflow tank was full on one side with nowhere for the coolant to go except puke out of a little opening where the cap screws on. Looks like the reason for the gap in the threads.

 

RA303 -

No pressure build-up as you slowly remove the radiator cap as I mentioned above?

An indication of coolant in the crankcase is a light brown milky foamy film under the oil fill cap. Of course, if you drain the oil into a clean drain pan, you will be able to see the separation of water as you get toward the bottom of the drain pan when emptying it.

If you don't see any indication of water you can pull out the t-stat (have a replacement on hand...with gasket). The t-stat is found by following the top radiator hose back to the engine. The hose attaches to the neck of the t-stat housing. Drain part of the coolant mix from the radiator through the radiator drain valve/plug at bottom of radiator to a point where you think that the coolant level will be below the t-stat housing level.
Remove the t-stat housing bolts with the upper hose still attached (if you can reach the bolts of course...just one less thing to hassle to re-install). The t-stat will be sitting under the housing. Make note of its position. Remove to test or just replace at this time and reinstall. If you test the original t-stat, the t-stat will start to open at around 194 degrees F (factory t-stat).

Regarding the coolant resevoir being split, I will guess and say that the divider is nothing more than a "dam-like" overflow to make sure that there is sufficient coolant level to be pulled back into the radiator when your engine cools.

I haven't noticed the cap on the reservoir...but I will look at it to see what you have stated about the spring and "puke" hole.

 

Ok, I checked the bottom hose and it wasn't very squishy, it was just like the upper hose. I checked the oil again today after a 30 mile drive on the freeway, 90+ degrees, a/c on. It once again looked perfect. All gauges were on the mark during my drive also. This afternoon I did the cold start test by myself. The truck was sitting for about 1 1/2 days so I pop my hood and get everything ready. 1. Started the motor, left running for about 5 seconds then killed it. 2. I ran to the cap and unscrewed it slowly, there was a little hiss of pressure venting but nothing major? Did I do it wrong? Doesn't the coolant build up pressure anyway?

Call me stupid, but I can't find the "radiator" cap? The only cap in that engine bay for coolant is the one on the overflow tank? It has all the warnings on it not to open hot, 16psi, etc...

Somebody recently mentioned that I may have had too much coolant in the system and this hot weather finally pushed it to the puking limit?

The truck is 1 1/2 months out of warranty (go figure) and has 34,000 miles. I'm almost paid off and really don't want to trade it in for another 4 years of payments. But if I'm scared everytime I drive it then 04 F-150 here I come

 

RA...

I must apologize...forgot about no radiator cap...only the reservoir cap....so checking for pressure buildup at the reservoir is not a diagnosis. The only way to determine for sure is to get it checked by a mechanic who has the equipment to diagnosis a possible HD leak using a combusion gas detector on the cooling system.

Someone suggested an overfilled reservoir when cold...after the engine warms up, then it will force out the excess as the coolant mix expands.

If you haven't noticed a loss in power or developed an engine miss and if the reservoir was not overfilled, then I would tend to think that the thermostat hung up. If you haven't had a cooling service done (at 24-30k miles) then I would suggest do it. I would also change out the thermostat with a new factory (194 Deg) while you're flushing the system.

 

Were you driving your truck hard and was it particularly hot? How long was it from getting off the freeway to reaching the gas pumps and shutting down the engine?

Sometimes, an engine that's driven really hard will actually be hotter than normal, irregardless of what the temperature gauge, even a real one, says. If you shut down an engine that's been run real hard without allowing it to cool down by driving normally or letting it idle for a few minutes, you can end up with coolant in the engine boiling.

 

Dennis, I wasn't being too brutal on the motor. Just the occasional dropping of the gear to pass a few cars, and Floored it twice to keep a ricer behind me It was also in the evening(6:00) so the outside temps were probally in the high 70's-low 80's. The gas station was about a 1/4 mile off the freeway and i was stuck at a light for about a minute.
I keep driving the truck and it hasn't even hinted of a problem so I'll just keep monitoring my oil and gauges and hope for the best. Plus the wife is all for getting an 04 I just might bite because the dealer can't haggle w/ X-plan!

 

My 97 4.6 did that a few weeks ago, topped off coolant replaced recovery tank cap and its been fine since.