Coolant Overpressure Help Help
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Coolant Overpressure Help Help
Navigator 5.4 1998 4x4 218000 Miles
Hello,
I'm French, writing from Normandy.
I have a Lincoln Navigator, which has a strange problem :
Start at cold, temperature engine rising normally, drive cool, in range 1500/2000 T/mn (45-50 MPH), 2-3 miles OK, when temperature falls slowly, close to zero (heater blown cold), at this time (I reproduced at idle one time) the coolant tank is full and the coolant projected out by overpressure during 4-5 mn, after in the tank the coolant decrease fast under the mini level and then temperature rise quickly at the norm ! And all is ok.
You can start all the day is ok, the problem appears only when the engine is absolutely cold.
When you open the coolant tank and smell it : it smell the gas !! As Vapor of gas were in the circuit !! That's strange !
No leak apparent. engine oil is clean. I changed the thermostat.
Have you an idea to help us (my mechanic do not understand why)
Thanks
My apologies for my poor English !
Hello,
I'm French, writing from Normandy.
I have a Lincoln Navigator, which has a strange problem :
Start at cold, temperature engine rising normally, drive cool, in range 1500/2000 T/mn (45-50 MPH), 2-3 miles OK, when temperature falls slowly, close to zero (heater blown cold), at this time (I reproduced at idle one time) the coolant tank is full and the coolant projected out by overpressure during 4-5 mn, after in the tank the coolant decrease fast under the mini level and then temperature rise quickly at the norm ! And all is ok.
You can start all the day is ok, the problem appears only when the engine is absolutely cold.
When you open the coolant tank and smell it : it smell the gas !! As Vapor of gas were in the circuit !! That's strange !
No leak apparent. engine oil is clean. I changed the thermostat.
Have you an idea to help us (my mechanic do not understand why)
Thanks
My apologies for my poor English !
Posting Guru
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Not to be mean or anything, but is he really a mechanic? All these are classic symptoms for blown head gasket. Smell of gas in the coolant is a dead give away. Do a compression test, might be on one side only if you're lucky, though might as well do both while you're at it.
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Ok we thought also a the head gasket. I will do a compression test.
But the oil is absolutely clean and the problem is only when the engine is cold, when is hot not problem with the coolant. it's the reasons why we are in the doubt .
Thanks
But the oil is absolutely clean and the problem is only when the engine is cold, when is hot not problem with the coolant. it's the reasons why we are in the doubt .
Thanks
Posting Guru
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Depends on how the head gasket failed. It does not always lead to coolant in the oil, but gas smell and pressure in the coolant is really a dead give away for failed head gasket. Did it overheat before this happened? Don't just blindly replace the head gasket, or you'll likely have the same problem again in the near future. Find the root cause for the head gasket failure, like warped head or similar.
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I bought it used, last year, and during this time never overheat. I drive fast but not at 5000T/mn. But before I bought it I did not know how was servicing !
Ok the head gasket, I will need to control the cylinder head surface .
Thanks for your help
Ok the head gasket, I will need to control the cylinder head surface .
Thanks for your help
Fleet Owner
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As the engine heats up the metals expand and close any gap that is allowing compression to pass through. Eventually it will get worse and the problem will be there when the engine is hot or cold.
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If you plan on scrapping the vehicle in a few months or selling it and make it someone elses problem, go for it. But if you plan on keeping it for a while, the stop leak stuff usually just makes things worse. It's hard enough to replace a head gasket, but after that stuff you have to clean the whole engine as well and make sure all the passages are clear and has good coolant flow.
