How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask AZTechBrian Your Own Question
AZTechBrian, ASE Certified Technician
Category: Mercury
Satisfied Customers: 708
Experience:  Owner
Type Your Mercury Question Here...
AZTechBrian is online now
A new question is answered every 9 seconds

I have a 2008 Mountaineer with a 4.6 it runs the coolant

Customer Question

I have a 2008 Mountaineer with a 4.6 it runs the coolant reserve dry after a few days of driving and radiator is low, no coolant on the ground no coolant in oil no coolant coming out of exhaust and heater core does not leak. any ideas
Submitted: 1 year ago.
Category: Mercury
Expert:  AZTechBrian replied 1 year ago.

Hello. My thought is that you are leaking coolant slowly and as you drive it blows away. Do you have access to a pressure tester that you can put on the system and let it be for a while to see if you end up with a puddle? It's most likely leaking from the water pump or the radiator but there are many other places it could be leaking from.

Customer: replied 1 year ago.
no pressure tester
Expert:  AZTechBrian replied 1 year ago.

Ok. If the leak is not obvious, then we will need to use a pressure tester to determine where it's leaking from. First, use a flash light and inspect everything very carefully. Something is going to be wet with coolant. Look under the water pump, bottom of the radiator, etc. If you don't find anything, then you can rent a radiator pressure tester from auto zone I believe, and I think they will return the rental fee upon return of the tool. This is the only way to know where that coolant is escaping if it can't be seen otherwise. Again, I see it often where it leaks slowly, usually from the water pump or radiator, so slowly that it only leaks when the system is hot and under pressure and it blows away while driving and you never end up with a puddle. Not until the leak gets bad enough.

Water pump is the most common cause of coolant loss though.

Customer: replied 1 year ago.
Last night I saw where it is leaking somewhere around the right rear side of the engine but can't see where it is coming from
Expert:  AZTechBrian replied 1 year ago.

Ok. It's probably the water pump leaking and running down before dripping where you see it, but it could be a freeze plug, coolant hose, etc. It may take a little investigating to find the exact location of the leak, but you will want to locate it and get it fixed before it gets very bad. You don't want to end up over heating and doing engine damage.

Customer: replied 1 year ago.
if it was the water pump it would be leaking at the front of the motor not right rear area, right?
Expert:  AZTechBrian replied 1 year ago.

The water pump is located in the front, but I have seen many times where the leak presents itself in the rear because the coolant runs down the engine and doesn't drip until it reaches the lowest point which is many times toward the rear of the engine. To determine whether or not that's the case you would have to take a look under the truck at the water pump and see if that's where it's coming from. If not, It could be a freeze plug, or a coolant hose to the heater core, etc.

Expert:  AZTechBrian replied 1 year ago.

what we can confidently rule out is a radiator leak

Customer: replied 1 year ago.
okay do not think it is the water pump could not see coolant leaking there, does this have a plastic intake that might have cracked or any pressed tubes back there that might be a cause
Expert:  AZTechBrian replied 1 year ago.

You do have a plastic intake plenum, but coolant does not flow through it on this engine. Here is a diagram of your entire cooling system. The only way to be certain of what it is, is to inspect it good and if necessary, a pressure test will amplify the leak to a point where you should definitely be able to determine the source of the leak.

Expert:  AZTechBrian replied 1 year ago.

Did you find the source of your coolant leak?