Blown motor or head gasket?

[Spiderplow]

This past march I had a pretty loud tap on start up and then it would go away when warm. I had an appt to bring to the dealer, and the day before I lost my heat in the car. I was on the highway and my 03 MM started shutting down. I limped off the highway and she wouldn't budge. Had it towed to the closest dealer and they said I had the wrong thermostat, but it could be bigger problems since it would only run under 40mph. Been sitting in the garage ever since and have been deciding what to do. It has 189k of my miles on it, and not sure what is wrong or what to invest to fix or find out. Any easy way to tell if its a blown motor or just a head gasket? Dealer could tell without more $$$.

[fastblackmerc]

This past march I had a pretty loud tap on start up and then it would go away when warm. I had an appt to bring to the dealer, and the day before I lost my heat in the car. I was on the highway and my 03 MM started shutting down. I limped off the highway and she wouldn't budge. Had it towed to the closest dealer and they said I had the wrong thermostat, but it could be bigger problems since it would only run under 40mph. Been sitting in the garage ever since and have been deciding what to do. It has 189k of my miles on it, and not sure what is wrong or what to invest to fix or find out. Any easy way to tell if its a blown motor or just a head gasket? Dealer could tell without more $$$.

Was the correct stat installed and system burped?

[MMBLUE]

If it spins over, try taking out the stat and run it without it and see what happens. It wouldn't cost you anything to give it a try. It's pretty easy to get to and take out.

[crouse]

Donate it to this guy.

http://www.mercurymarauder.net/forums/showthread.php?t=95002

[Bigdogjim]

If it was running under 40MPH then the fail safe kicked in.

[EMAS]

Do not run it w/o a thermostat that will cause it to overheat since the thermostat is of the bottom bypass blocking type and w/o the thermostat in place the coolant won't go to the radiator it will return to the block.

When it gets hot it goes into fail safe mode that limits power output and eventually shuts it down when it gets hot enough.

So make sure it has the correct thermostat in it and the system is burped and drive it. Then see if you can find out if there is a leak.

[RF Overlord]

Do not run it w/o a thermostat that will cause it to overheat since the thermostat is of the bottom bypass blocking type and w/o the thermostat in place the coolant won't go to the radiator it will return to the block.Excellent info, thanks!

[MMBLUE]

Do not run it w/o a thermostat that will cause it to overheat since the thermostat is of the bottom bypass blocking type and w/o the thermostat in place the coolant won't go to the radiator it will return to the block.

When it gets hot it goes into fail safe mode that limits power output and eventually shuts it down when it gets hot enough.

So make sure it has the correct thermostat in it and the system is burped and drive it. Then see if you can find out if there is a leak.


Running it for a few minutes without the stat isn't going to hurt nothing. Are you saying that the water isn't going to flow because of a T-stat out??? That is what a water pump does.

[sflrainmaker01]

Running it for a few minutes without the stat isn't going to hurt nothing. Are you saying that the water isn't going to flow because of a T-stat out??? That is what a water pump does.

He's saying that with the thermostat out, water will not get routed to the radiator for cooling. The water will circulate back through the engine and get even hotter. At least, that's what I got out of it.... ;)

[fastblackmerc]

It won't hurt to run w/o the stat for a few minutes.

[EMAS]

It won't hurt to run w/o the stat for a few minutes.

But running it for the short period you can get away with w/o the thermostat won't tell you anything that you can't figure out with the thermostat in place. So pulling the thermostat, putting it back together, and going through the process of properly burping it wastes a lot of time.

[Bigdogjim]

Funny that this topic pop up because my marauder been sitting for 5 months with an overheating issue:mad:

[vegasmarauder]

I'll bet about half to 3/4 of the overheating issues are due to low coolant. It seems that every place (including the Ford dealers) just looks at the degass bottle (overflow tank) and of course it always will look full even if you are up to a gallon low on coolant. You have to pull the plug from the crossover tube to properly check the coolant level. If it's low, then fill/burp according to (numerous) previous posts. I have fixed 2 MMs with overheating issues by simply filling the coolant. Of course, one did have a seeping crossover tube o-ring that was causing the coolant loss, so look for tiny leaks anywhere in the system as well.

[massacre]

All the more reason to get the On3 kit and put the thermostat in the upper hose like a normal car, instead of the stock remote thermostat in the lower hose.

[Spiderplow]

Why is your plan BigDog with the MM?

[CrownVictorious]

x100 on everything said. Was your car throwing codes? Your car may be overheating due to a blocked radiator. This or other cooling issue such as low coolant or blockage would cause the car to overheat. Does your car buck with acceleration like a misfire? The car has a failsafe that triggers through the CHT sensor. This sensor detects a heat range and once it gets hot enough it will first shut off every other cylinder in an effort to dissipate the heat - it will also shut off operation to any AC setting. If the heat continues to rise, the car will shutoff the engine in an effort to save itself from any further damage.

Hope this helps

[Bigdogjim]

Why is your plan BigDog with the MM?

What is my plan? Fair question. Let it rust!:help: