My father has a 2000 Ranger supercab 4x2 with the 3.0V6 and 160K miles.

About one month ago he was on way to work and the temp gage went up and he could smell coolent, then the gage went down and when he got to work and check the coolent level it was low. Took over a gallon to fill, and ever since it looses about a quart of coolent to 100 miles. He took it in to the shop taht does all of his work and they replaced the Tstat and flushed the system, but the coolent loss continued. The shop then did pressure check and put die in to check for leaks. Pressure check was ok and they say no trace of coolent in oil and they did a test for a head gasket leak that came back negitive. No coolent drips on the ground and the underside of truck is clean and dry.
The shop has given up, they can't find the leak.

I think it is leaking from the intake manifold or a hose close to the intake and as it drips it evaporates on the hot engine.

Any ideas on what hose or gasket could be leaking?
Why did it hold pressure?
He is having to fill the overflow jug daily, and no white smoke from exhaust.

Thanks for the help.
Dan

 

Keep an eye on the radiator end tanks, sometimes they like to seperate from the core and leak only when the system is under pressure.

 

A leaky intake manifold is indeed a possible cause. My brothers ranger with a 4.0 never held coolant after 100k miles. We replaced the intake gaskets and and now all is well. Another possible cause is a leaky heater core. Does your father have a problem with his windows foging up at all? Do you get any dripping in the passenger compartment? Usually if you inspect the intake manifold (the area around it) it will sometimes reveal a leaky spot.

 

Thanks guys. He says no dripps on ground or under truck, I had a rad leaking in my 92 Escort Gt and the tanks were wet and I had a puddle on the ground. He says the windows do not fog and he can smell coolent out side the truck if the engine is running and window down.

Got to be evaporating somewhere but must also be a good size leak fo rthe amount of coolent loss each day..

 

Check the heater valve. It is inline with the heater hose going into the cab. This valve is supposed to be on all the time unless the system is OFF or in MAX A/C.
I just replaced mine last year, but it is leaking again. This time I can see a small drip under the truck after I park it. But the first time it went bad I could smell antifreeze, but I could never find a leak.

 

Yeah I agree on the heater control valve. They get pretty brittle over time.

 

Sometimes coolant leaks when engine is hot only. If you feel smell, try to find where it leaks by smell.
Try to retorque all, clamps, ait intake bolts, intake manyfolds bolts.

Coolant may be in exaust. If there is coolant in exaust, try to retorque cyl. head bolt first, if leak will not dissapeare replace gaskets.

It is a good way to use stop leak adds to coolant, but I advice you to be careful, not to use too much ore to frequantly, becouse heater core may be clogged.

 

ive gotta with the intake gasket. my buddys 99 was doing the same thing in every way but it didn't use as much as your going through(maybe a gallon a week). we suspected the intake, before he could work on it the oil pump drive sheared and he blew the motor. we found a tiny crack in the intake gasket, we figured this was the problem.

was the engine warm when the guy did the pressure test? you might want to do it warm to check the heater control valve. i've seen them leak but only when running/ and warm

 

I can only assume he did the pressure check both hot and cold, as I know that my dad left the truck overnight with the shop.

I just called my dad and told him to look around the heater control valve and try to look in the valley of the motor for signs of coolent. They are driving the F150 from Minneapolis to Sioux Falls for Christmas today, so he may not get to it untill next week.
Thanks Dan

 

One thing I have learned is never assume. Mine leaks only when engine is cold. I have a small leak in the lower water pump gasket. I only lose about a pint every month(1K miles). It's been doing this for about a year. This spring I will replace water pump.

 

Look under the engine where the timing cover and block bolt together. This is where my 91 Ranger 3.0 leaked at. I put in stop leak to stop this problem.

 

I had the same problem with my 99' 4.0, dissapearing coolant with no visible signs. My mechanic checked all the hoses ect., and replaced lower intake gasket and that didnt sovle the problem. After reading sveral post on head gaskets leaking, I looked up through my wheel well and sure enough there was coolant strikes all down the side of the bock. So, like pablo-ua said, try to retorque the had bolts and if that dont stop the leak have them replaced. I hope you get it figured out.

mike

 

Thanks for all the replies, he will taking it in on Thursday or Friday to have oil changed and will tell the tech to look in thease places.

If he cannot find it still I will drive up and bring truck back to Sioux Falls to find it my self.
Dan

 

Update. After having the independent shop put in a tstat and test cooling system twice they found no leak.

Then my dad took it to the Ford dealer he bought the truck from. they had it for a few hours each on two different days and could not find the leak. Best guess from both shops was intake gasket?

I went and picked up the truck and left mine on Monday this week. I brought it back to the Ford dealer here in Sioux falls and in one hour i get call from service advisor, found leak at timing chain cover and to boot the new tstat gasket was crushed and leaking too.

I plan on driving it for another week to make sure all is good before giving back to Dad.

Thanks Dan

 

I put about half a bottle of stopleak in mine, seems to have stopped the leak for now.Its been over a year, so I hope its stopped for good.