My mechanic has replaced the thermostat and housing, still leaking, then he replaced the water pump and pressure tested all seemed well. Still losing coolant so he did the test with the dye in the coolant to check for head gasket, he said it passed, there is no sign of a leak, no oil in antifreeze or antifreeze bin oil. Any ideas??? What about intake gaskets. I ordered a new coolant reservoir with cap, just haven't put it on yet

 

Did you check the bleeder housing. It is plastic and is a common problem on the 2.7's. It can leak around the base and not be very noticeable.

John

 

Try changing the cap on the plastic coolant tank. It's a radiator type cap and it can let coolant escape when it starts to wear out. There is a hole in the side of the tank where coolant can escape.

 

I will check that, thank you.

 

I ordered a new coolant tank with cap, will change it out, any one use the coolant sealing pellets to seal leaks?

 

"any one use the coolant sealing pellets to seal leaks?"

Stay away from those things. They can clog the system up. Which engine do you have?

 

02 2.7l with 91000 miles. The pressure release valve was changed last year. Could it need changed again? Also there is a strong odor of fumes or exhaust (not straight fuel) in the engine bay which makes it way through the cabin vents, thought the heater core but the floor is dry as a bone. Still have to change coolant tank could a bad tank or cap cause the loss and not see an actual drip. We are putting a gallon of 50/50 mix coolant in every 4-6 weeks
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Replacing the water pump on the 2.7 L engine is a BIG operation. It requires taking off the timing chains and pretty much everything else on the front of the engine. If you paid for all of that work and you still have a leak then perhaps you should sit down and have a serious talk with your mechanic. As for bleeding the system, if you turned the bleed screw on top of the engine, chances are very good that you stripped out the seat into which the bleed screw sits. It is a metal seat that is not retained very well in the plastic housing. Turning the screw causes the seat to turn, stripping out the plastic and causing a leak. Been there, done that. The best way to bleed the system is to let it bleed itself in the course of a few warm-up and cool-down cycles and then top up.
There are leak detection additives you can put in the system that will show up under "black light".
If you are getting an exhaust fume smell in the engine compartment, that's a totally separate problem. However, you may be smelling antifreeze running onto hot engine parts. If that's the case, your leak is on top of the engine somewhere. The bleed screw in the water outlet manifold on top of the engine would be a prime suspect.
The only "pressure release valve" is the radiator cap. They don't last forever and are cheap and easy to replace. If the cap is bad, there will be a loss of coolant under the car, but it's conceivable it might only blow off while the car is in motion and you might not notice it when parked.

 

If you are leaking that much coolant there's no way it could pass a pressure test. I have to question your mechanics competence or honesty. How much did you pay to have the water pump replaced. Most mechanics will charge between $1000-1300 for parts and labor to do it. If you paid substantially less then the pump wasn't replaced.

John

 

Well I put on the new tank and purged via the bleed valve, but noticed prior to changing and after that the lower radiator hose never gets hot. Suspected a plugged radiator, well, had the hole system flushed yesterday and still after running it for an hour purging and adding we still have a cool lower radiator hose, has not overheated, and heat works good, till you turn it off. As soon as you restart it the heat soils down, but as soon as you give it gas boom it blows hot again