New Problem: Temp Gauge.99 4.0 sohc

[opus007]

My temp gauge is staying way below normal and hardly registering at all.When I shut the engine off and turn the key to the on position without starting the engine the gauge rises but if I start the engine the gauge goes down.Also I am now noticing like marbles rolling around some where in the engine.The top hose is warm but the bottom house is a lot cooler.Any ideas.Thanks.

 

[Big Jim M]

My temp gauge is staying way below normal and hardly registering at all.When I shut the engine off and turn the key to the on position without starting the engine the gauge rises but if I start the engine the gauge goes down.Also I am now noticing like marbles rolling around some where in the engine.The top hose is warm but the bottom house is a lot cooler.Any ideas.Thanks.

The top hose is where the HOT coolant comes out of the engine.. It's sposed to be hot!
The bottom hose is where the coolant goes back into the engine...after it is COOLED by the radiator. It's sposed to be lots cooler than the top hose.

Find the gauge temp sendor and getcha a new one for a few bucks and see if that does the trick.. Meantime take the cap off when the engine is cold and look to see if the radiator is full of coolant.. If not then get it full of new coolqnt.
Big JIm

 

[opus007]

yes it is full of coolant and truck does not seem to overheat.Will get a new temp sensor tomorrow and hope that fixes it.

 

[opus007]

Also where is the temp sensor located?and do I need the sendor or the coolant temp gauge?

 

[Big Jim M]

These gauges are pretty reliable. It is the sendors that go away. Sometimes even a little dirt on the sendor connection will give false readings on the gauge.
Both temp sendors are on or near the thermostat. One is for the gauge and the other is a temperature switch for the computer.
Big JIm

 

[289-tiger-]

You may have a thermostat stuck in the open position, it got cold in my 93 with this issue this winter. Electric gauges and their sending units are semi-reliable, but sounds like your guages are working.

Good luck

 

[opus007]

Tested the sender and it is fine.Took my truck to Ford as the head mechanic is a friend and he also said stuck thermostat.Says stuck open.Am going to replace the theremostat and sensors to be safe today.Unfortunatly the dealer does not have the thermostat and had to order it.Since I get a employee discounts it is not a lot of money.18 bucks for the thermostat and 8 bucks each for the sensors.Also will replace all fluid.Anything I should know before I get started.Thanks.

 

[289-tiger-]

Tested the sender and it is fine.Took my truck to Ford as the head mechanic is a friend and he also said stuck thermostat.Says stuck open.Am going to replace the theremostat and sensors to be safe today.Unfortunatly the dealer does not have the thermostat and had to order it.Since I get a employee discounts it is not a lot of money.18 bucks for the thermostat and 8 bucks each for the sensors.Also will replace all fluid.Anything I should know before I get started.Thanks.

Simply follow the instructions in your repair manual (a thermostat is pretty straightforward) and make sure to burp all of the air from the system when refilling with the heating system in the loop.

A helpful hint when replacing a thermostat is that occaisionally they could have a defect when new, I always boil them in a pan of water to assure they open properly. Have fun

Good luck

 

[opus007]

installed a new thermostat.Sort of fixed the gage problem.Before I could drive my truck on a cool day and would not go near half way on the gauge.Now it goes there after 10 minuets of ideling.Also If I remove the radiator cap from a cold start and after a couple of minuets coolant slow comes out of the radiator.Never did this before.I just took the thermostat back out and put it in a pan of water and boiled it.It did not open till after 200 degrees or just when the water started to boil.I took it to Ford earlier and they checked for air in the coolant and said it was fine.It does not over heat with the new thermostat but it goes to half way on the gauge pretty quickly and stays there and goes no higher.Is this ok and what about the fluid coming out at a cold start from the radiator with the cap off after a few minuets.Any ides.Thanks

 

[Big Jim M]

ANYTHING gets larger when heated! Including coolant! So as the temp builds up in the engine the coolant GROWS in size That is what you have witnessed. Normally that coolant would build up pressure and when 16 pounds is reached the cap would allow some of the coolant to go into the coolant tank.
Then when the engine cools down the coolant inside the engine SHRINKS and causes a vacuum in the coolant system.. at this time the coolant is SUCKED back from the tank into the engine.
Thats the way it works. I'd say you have a completely NORMAL engine coolant system.
Big JIm

 

[Big Jim M]

BTW! Your engine should normally run at about 210* and will keep it's coolant inside the engine untill about 235* is reached. Because at 16 pounds pressure the water in the coolant will boil at near 235*..
Here in Austin I use pure antifreeze with no water added. MY coolant won't boil until over 300* is reached. And my engine is protected to about -5*... plenty good enough for Central Texas. Even at -5 the pure antifreeze only gets slushly and doens't freeze hard.
Big JIm

 

[opus007]

Thanks for the info that helps out a lot.
One last thing ,when I checked my transmission fluid (per owners manual) it read about a inch higher than where it should be.I had the trans fluid replaced a couple of years ago ,actually about 5 years ago and have never checked it as I ussualy take my truck in for oil change and tune up.Is there a way to drain some out or should I take it in and have new put in.I have never had any leaks or trans slippage.Thanks.

 

[Toms01PSD]

Use a fluid extractor stuck down the tranny dipstick tube.

http://www.autoexpress.co.uk/products/products/203133/house_of_hastings_fluid_extractor.html

 

[Big Jim M]

Too much tranny fluid doesn't hurt one damn thing! If it gets too high it will run out the overflow.. AND then it will be ok after it levels itself..probly still higher than the full mark.
Now too low is another thing. Too low might get the fluid too hot..or even not have enough to shift gears..or whatever. But too high only risks running out the overflow.
Big JIm

 

[Yellowsplash]

Here in Austin I use pure antifreeze with no water added. MY coolant won't boil until over 300* is reached. And my engine is protected to about -5*... plenty good enough for Central Texas. Even at -5 the pure antifreeze only gets slushly and doens't freeze hard.

Not to get picky, but I should point out a few things....
While antifreeze has a higher boiling point than that of water, water has much better thermal transfer properties that allow it to dissipate the heat much more efficiently. Pure antifreeze might not be the best for all people in different seasonal climates. This is why a 50/50 mix is usually advertised. As far as cold is concerned, 50/50 is rated to something like -28. I dont usually see negative numbers here too often, so 50/50 is adequate for me. Hell, If it werent for cold climates and rust prevention, pure demineralized/distilled water would be just fine.