Cracked exhaust manifolds?

[PacS14]

Ok so I've had now two alternators go bad within 6 months of installation, the first was definitely because of oil leaking from the cam seal, I've since replaced those seals and timing belt, water pump, etc. I flushed the cooling system because it was due. Now I can't say about before because honestly I never paid attention to the temperature of the engine bay as I would always let it cool down before working on it, but this time I was like there must be something else since other members have reported going through alternators like I have, also read about exhaust manifolds cracking; then yesterday while waiting for my wife outside the doctor's office I noticed my temp gauge climbed up rather quickly (I hardly ever have a reason to wait for someone that long inside the car with the ac on), also the ac cold air got warmer really quick, now I know this is Houston and is hot but none of my cars AC have ever acted like this without having some sort of AC issues. Then I got out to open the hood and the hood support rod was too hot to touch and the engine bay was almost like a BBQ grill hot, I have opened the hood of other cars I have owned while hot for one or another reason and this is the first time I felt I was going to get a burn just by opening the hood. So now I'm leaning towards testing for leaks in the exhaust manifold, which I will do later on today.

1- Am I right to believe that heat soak would also be the reason for my alternators going out? I can always replace it since I got the lifetime warranty, but I want to fix the heat in the engine bay as it also affects my AC.

2- I have seen cast iron manifolds on ebay, anyone here got them on yet? I know is flea bay, but at that price range I might try it and report the outcome if no one here has tried them.

3- I will also test the clutch fan, any other suggestions?

 

[jeep-N-montero]

Mine did the same exact thing the other day at Cabela's, wife sat in Monty while I ran inside to exchange a few things, when I came out it was blowing warm air. After we got going it improved a little bit but not what you would expect, but with all of this hot weather I'm sure it takes its toll, we have been over 100 a few times already and it's not even July yet. If you had a cracked manifold you would USUALLY hear it and possibly get a CEL, but not always, but cracked or not your alternator will not like to sit and idle in this heat.

 

[PacS14]

My AC worked fine once I got going. I will look more into it as soon as I get home today. We had high temperatures and the humidity here makes it worse. I saw condensation on the metal AC lines and like I said the entire engine bay was too hot for confort.

 

[RyanY]

A cracked exhaust manifold is not going to add a significant amount of heat to the engine compartment. Your heat issue sounds like the electric fan on the front of the radiator isn't working properly, possibly in combination with a bad fan clutch. The fan should spin freely when cold, but after warming up should be almost locked to the engine - if it's not then it needs to be replaced. The electric fan should come on whenever the a/c is on.

Keep in mind that sitting and idling for an extended period of time in higher temps with the a/c on WILL cause heat soak in many areas under the hood. The cooling fans are only designed to move air through the radiator and condenser, and to a lesser degree, the engine compartment itself, but they aren't going to keep your prop rod cool nor move the same volume of air that driving does.

The most likely cause of your alternator failure is that its a cheaply rebuilt aftermarket alternator instead of an OEM Mitsubishi alternator. Having your original alternator rebuilt is always a better idea than buying a reman alternator from your local parts store, especially AutoZone.

 

[PacS14]

A cracked exhaust manifold is not going to add a significant amount of heat to the engine compartment. Your heat issue sounds like the electric fan on the front of the radiator isn't working properly, possibly in combination with a bad fan clutch. The fan should spin freely when cold, but after warming up should be almost locked to the engine - if it's not then it needs to be replaced. The electric fan should come on whenever the a/c is on.

Keep in mind that sitting and idling for an extended period of time in higher temps with the a/c on WILL cause heat soak in many areas under the hood. The cooling fans are only designed to move air through the radiator and condenser, and to a lesser degree, the engine compartment itself, but they aren't going to keep your prop rod cool nor move the same volume of air that driving does.

The most likely cause of your alternator failure is that its a cheaply rebuilt aftermarket alternator instead of an OEM Mitsubishi alternator. Having your original alternator rebuilt is always a better idea than buying a reman alternator from your local parts store, especially AutoZone.

Thanks for the info! I will test the fan clutch in the morning to make sure it works since is the only time it will be cold for sure.

 

[nwoods]

Not the fan clutch (although that could be an issue), but the electric fan in front of the radiator. Its the A/C system fan, and my runs pretty much all the time. When I first got my Monty, it wasn't working and frequently overheated at idle speeds (like, on the trail). A buddy "sourced" one from the junkyard for me, and it was literally plug and play. No more overheating. My truck is rock solid in the middle of the temp gauge....or was until the water pump died, but that is a different story for another time.

 

[PacS14]

Not the fan clutch (although that could be an issue), but the electric fan in front of the radiator. Its the A/C system fan, and my runs pretty much all the time. When I first got my Monty, it wasn't working and frequently overheated at idle speeds (like, on the trail). A buddy "sourced" one from the junkyard for me, and it was literally plug and play. No more overheating. My truck is rock solid in the middle of the temp gauge....or was until the water pump died, but that is a different story for another time.

I replaced the motor for the ac condenser fan with a new one about a month or two ago and mine works great now so i know is not that.

The clutch fan was not free spinning this morning, I mean it would spin but would come to a stop almost immediately after I pushed it. So I'm going to read more about this one because I had a Toyota T100 and supposedly that is the way it should be when cold, will look into the manual for the montero later on and see what I find.