Gaskets & Engine Heads


#1

Bear with me a/c I’m new at this. Can a professional mechanic determine whether problem is a gasket or cracked head? Do they routinely use process of elimination?


#2

To answer your questions, yes and yes. You’ve had a mechanic tell you that you either have a cracked head or a blown head gasket and you don’t feel comfortable with his diagnosis? More information please. Year make model symptoms background.


#3

It’s really more a case of exploratory surgery. But, the chances of a cracked head can sometimes be made depending on the method of failure. Also, some engines are more prone to cracked heads due to overheating than others. But, until the head is removed and examined can anyone be certain of a blown gasket or cracked head. I always send my heads to a specialty shop to be examined and fixed. They have more specialty equipment to correct defects that can happen to cylinder heads after years of service.

I recently did a blown head gasket on a 1999 Volvo S70. The 5-cylinder engine design had an aluminum cylinder head that was prone to severe warping when overheated. My shop guy has equipment that can de-stress and re-flatten the head enough to resurface the head and return it to factory specs. He didn’t have to do it, but it was nice to know he could if necessary.


#4

Car was over-heating and “slight leak” is noted on all mechanic bills. Early Oct. they put in new water pump, thermostat & timing belt. Mon. it overheated & has been at dealer all week. Diagnosis was gasket, but today I was told I can’t get it back till next Mon. a/c mechanic "moved a bolt that broke new gasket & they have to re-order. Someone suggested to me it might have been a cracked head that they are trying to weld? Any of this make sense to you? And thanks for responding.


#5

Sorry, its a 97’ Ford Contour.


#6

As far as I’m concerned, the diagnosis of a cracked head is wrong way over 99% of the time and generally a wild guess.

There is no way of determining a cracked head with the cylinder head in place on the engine. Even when removed it may be near impossible to determine this and to knw for sure the head needs to go through some specialized tests such as X-ray, Magnaflux, Zyglo, etc.

With the head removed,what should be done before even considering the possibility of a cracked head is perform a careful inspection of the head gasket. A leaking head gasket will often leave signs of the fault. A few minutes of careul inspection is much better than blindly throwing another head gasket on or giving a diagnosis of cracked head.

(For what it’s worth, I’ve been “mechanicing” close to 40 years (over 30 with aluminum heads) and I’m still waiting to see my first performance or overheating problem caused by a cracked head).


#7

They probably would tell you if the head were cracked, they know you’d be back the next day if they put a new gasket under a cracked head. They don’t want you coming back and demanding a free fix.


#8

Is it normal to take a week to replace a gasket, and would you notice a leak there when replacing a water pump? I guess I’m just wondering why I’ve spent almost $3,000 for “over heating & a leak” and I appreciate your input.