Leak in a head gasket requires a COMPLETE engine rebuild is that so or poppycock?

[Soul Reputation]

I have an '87 Mustang that a mechanic told me has a small leak in the head gasket area. He told me that on a scale of 1 to 10 it was a 1 (a minor issue) and that I could continue to drive it without incurring any damage. He basically said 'At this point I wouldn't worry about it. It's a small leak so go ahead and drive the thing.' Yep, a mechanic actually turned me away as we stood standing in front of my car with the hood open while staring at the problem area thereby declining the opportunity to make a few bucks for himself.
Later this one person comes along (we'll call him 'Jim') and Jim says and I quote 'A head gasket is a huge deal! That is a motor rebuild!!' Can I trust Jim? Talk about two opinions that differ like night and day.
A motor rebuild? My mechanic never said nothing about a complete engine rebuild.
Now it's time to rate what Jim said. Rank what Jim said on a scale from 1 to 10 with #1 being an over the top moronic statement and #10 being an on-the-money mechanical genius-like statement. I need to find out what's what so no matter what you're opinion is on this subject even if it's bad news please don't hesitate and scroll down to the bottom of this post if you need to define poppycock.

poppycock [ˈpɒpɪˌkɒk] noun
Informal senseless chatter; nonsense
[from Dutch dialect pappekak, literally: soft excrement, from pap soft + kak dung; see pap1]
Collins English Dictionary – Complete and Unabridged 6th Edition 2003. © William Collins Sons & Co. Ltd 1979, 1986 © HarperCollins

 

[Lotheron]

In a word No a complete rebuild is not required. As long as there is nothing else wrong with the engine then the heads will need to be removed and a new gasket placed.

I would try to find out what caused the head gasket to fail though.

 

[Fenixgoon]

IANAM (i a not a mechanic), but it's about half and half IMO with the favor going towards your mech. You definitely don't need a full rebuild - you just need to take off the head to replace the gasket (which can be quite time-consuming).

 

[JulesMaximus]

With all due respect, I would say that Jim is out of his freaking mind. All you need to do is remove the head and replace the gasket. It's not a small job by any means (you have to remove the intake and exhaust manifold to remove the cylinder head) but it does not need a full engine rebuild.

A typical engine rebuild would see you removing the engine from the car, removing the pistons & crankshaft, honing the cylinder bores, new rings, main bearings, timing chain, and all engine gaskets. This CAN be done with the engine in the car (depends on the car) but it is much easier to do with the engine out. It's probably one of the biggest jobs you would ever have to tackle on a car short of a complete body off restoration.

 

[Airborne!]

If it is your head gasket then the gasket needs to be replaced no matter how small the leak. If the blown gasket allowed coolant to leak into the cylinders then yes the engine would probably need some type of a rebuild. That is probably what 'Jim' is thinking about.
That being said. If your mechanic said "small leak in the head gasket AREA" then he might not be talking about the head gasket at all. You probably need to clarify with the mechanic what he means. I have never heard of a mechanic worth his salt telling someone to drive with a head gasket issue of any kind.

 

[Pacfanweb]

Here's where "Jim" was coming from:

Full rebuild, because nearly any mechanic that touches that car is going to find a lot more things wrong when he tries to replace the head gasket.

Furthermore, anything that goes wrong with the engine from here on out, the customer is going to blame it on him, and want it fixed for free. So if he replaces one head gasket for you and 3 months from now the other one starts leaking, you will probably be bitching at him, while claiming he should have been clairvoyant and known that would happen.

Also, if he's experienced, he knows that just disturbing an engine that's been together for a long time is very likely to cause other things to break, either while he's taking it apart, or shortly after you get the car back....and again, the customer will blame that on the mechanic.
You wouldn't think that removing an old part that is working perfectly and reinstalling it will cause it to fail, but by God, I've seen it happen literally HUNDREDS of times, and every experienced mechanic out that has, also.

So, IMO, most mechanics don't really WANT to rebuild the entire engine.....but they recommend this in order to cover their own asses because of the way customers are.

On the other hand, most of these same mechanics will also do just the head gasket if you really ask them to.....if they are smart, they'll ask you to sign something saying there's no guarantee that other stuff won't break soon after, etc, but most will do it.

 

[JulesMaximus]

Here's where "Jim" was coming from:

Full rebuild, because nearly any mechanic that touches that car is going to find a lot more things wrong when he tries to replace the head gasket.

Furthermore, anything that goes wrong with the engine from here on out, the customer is going to blame it on him, and want it fixed for free. So if he replaces one head gasket for you and 3 months from now the other one starts leaking, you will probably be bitching at him, while claiming he should have been clairvoyant and known that would happen.

Also, if he's experienced, he knows that just disturbing an engine that's been together for a long time is very likely to cause other things to break, either while he's taking it apart, or shortly after you get the car back....and again, the customer will blame that on the mechanic.
You wouldn't think that removing an old part that is working perfectly and reinstalling it will cause it to fail, but by God, I've seen it happen literally HUNDREDS of times, and every experienced mechanic out that has, also.

So, IMO, most mechanics don't really WANT to rebuild the entire engine.....but they recommend this in order to cover their own asses because of the way customers are.

On the other hand, most of these same mechanics will also do just the head gasket if you really ask them to.....if they are smart, they'll ask you to sign something saying there's no guarantee that other stuff won't break soon after, etc, but most will do it.

Complete and utter nonsense. Once the head is off he can check to see if he thinks it needs a valve job or resurfacing, he can also see if there is coolant in the engine before he even starts to disassemble it by checking the oil. If it needs a valve job and it's a V8 it's just a matter of taking off the other cylinder head and doing the valve job on both heads at the same time. Removing the cylinder heads is not going to cause other things to break and as long as the engine has been well maintained there is no reason to assume that working on it will cause other issues or bring to light other issues.

I wouldn't advise someone to just ignore a cylinder head gasket leak but at the same time I wouldn't be recommending a complete engine rebuild either.

Just out of curiousity, how many miles are on this engine anyway?

 

[AMCRambler]

You'll have to take your intake manifold apart/remove it and remove the heads. Beyond the new head gaskets and couple of gaskets/seals for the intake assembly, you won't be replacing anything else. It's not an engine rebuild.

An engine rebuild would be pulling the pistons, honing the cylinder bores, new rings, main bearings, timing set, etc. Only an issue if your head gasket is leaking a lot and the engine is not getting proper cooling or lubrication and you have a catastrophic failure. Spun bearing, thrown rod or the like.

 

[Lotheron]

You'll have to take your intake manifold apart/remove it and remove the heads. Beyond the new head gaskets and couple of gaskets/seals for the intake assembly, you won't be replacing anything else. It's not an engine rebuild.

An engine rebuild would be pulling the pistons, honing the cylinder bores, new rings, main bearings, timing set, etc. Only an issue if your head gasket is leaking a lot and the engine is not getting proper cooling or lubrication and you have a catastrophic failure. Spun bearing, thrown rod or the like.

If it really is the head gasket that is needing replaced and depending on the reason (such as an overheating engine) the heads might need to be looked at, but you're right, everything else you listed should still be fine.

 

[JulesMaximus]

I'm wondering if it is really a head gasket and not just an exhaust manifold gasket leak. Although, you'd think a decent mechanic would know the difference.

What is the compression like in each of the cylinders? Did you have a compression check done? Is there any coolant in the oil? Or sweet smelling white smoke coming out the tailpipe?

 

[AMCRambler]

If it really is the head gasket that is needing replaced and depending on the reason (such as an overheating engine) the heads might need to be looked at, but you're right, everything else you listed should still be fine.

Yeah that's true. Could warp the heads or fry the valve seats if it overheated. The heads would need to be rebuilt/replaced if that happened. If it were me, I wouldn't screw around with a leaking head gasket though. I'd get it replaced. The cost of an engine rebuild if it did suddenly get worse isn't worth delaying the work.

 

[Soul Reputation]

That being said. If your mechanic said "small leak in the head gasket AREA" then he might not be talking about the head gasket at all. You probably need to clarify with the mechanic what he means.

No, the mechanic didn't use the word 'area' i did. Anyway, most mechanical-savvy people who've seen the car notice a bit of oil in that area, as did this mechanic, in which case almost all of them say something like 'Hey looks to me like you've got a bad head gasket there' evidently it's kind of a no-brainer dealio for the mechanically inclined man or woman.

 

[Soul Reputation]

I'm wondering if it is really a head gasket and not just an exhaust manifold gasket leak. Although, you'd think a decent mechanic would know the difference.

What is the compression like in each of the cylinders? Did you have a compression check done? Is there any coolant in the oil? Or sweet smelling white smoke coming out the tailpipe?

It was a while back I can't remember if a compression check was performed but there was never any smoke coming from the pipe and plus I never changed the oil I always took it to a shop for that and none of the mechanics ever said anything about coolant in the oil. In checking the dipstick I never saw any coolant on it.

 

[Pacfanweb]

Complete and utter nonsense.

Says someone who's never done it for a living.

Mechanics all over the country, every working hour of every work day, recommend rebuilding/replacing engines and transmissions that could be repaired for the very reasons I gave.

To say that doesn't happen shows a complete lack of understanding how this industry works.

Now, that said, could the head gasket simply be replaced? Sure, and I said as much. Never even implied differently.....although I'd bet dollars to doughnuts that on an older car like that you'd find some other issues along the way.

But yes, it could be done. And that Jim fellow might well do it if pressed to. But to cover his own ass, his RECOMMENDATION would be to rebuild/replace the engine.

 

[Pacfanweb]

I'm wondering if it is really a head gasket and not just an exhaust manifold gasket leak. Although, you'd think a decent mechanic would know the difference.

What is the compression like in each of the cylinders? Did you have a compression check done? Is there any coolant in the oil? Or sweet smelling white smoke coming out the tailpipe?

Can't believe any competent mechanic would recommend engine work for an exhaust leak. That would be absurd. You don't even have to be a decent mechanic to know the difference.


OP: Are you leaking fluid? If so, what? Oil or coolant? That's all that could come out of a head gasket.

 

[Stefan Payne]

Complete and utter nonsense.

No, he's right!
A 23 years old engine isn't in a pretty good shape, it will have some 'battle damage' and will fail sometime.

And most of the damage done can't be seen, so a complete rebuilt is recommed.
The question is what's necessary for a complete rebuild.

I wouldn't advise someone to just ignore a cylinder head gasket leak but at the same time I wouldn't be recommending a complete engine rebuild either.

That's true, a damage head gasket has to be replaced - if not there will be massive damage to the engine!

And the complete engine rebuilt is recommed due to age, what is really necessary, you can only say after disassembling the engine.

Just out of curiousity, how many miles are on this engine anyway?

The milage doesn't say a thing.
It's more important how it was used.

You'll have to take your intake manifold apart/remove it and remove the heads. Beyond the new head gaskets and couple of gaskets/seals for the intake assembly, you won't be replacing anything else. It's not an engine rebuild.

You forgot to measure the block and head!
See if everything is as it should be.

It can happen that a head can be deformed.

An engine rebuild would be pulling the pistons, honing the cylinder bores, new rings, main bearings, timing set, etc. Only an issue if your head gasket is leaking a lot and the engine is not getting proper cooling or lubrication and you have a catastrophic failure. Spun bearing, thrown rod or the like.

An engine rebuilt starts with measuring the engine parts and see what has to be done and what's OK.
After that it's decided if the cylincers bores must be honed, if the pistons must be replaced or what else has to be done.

 

[JulesMaximus]

The milage doesn't say a thing.
It's more important how it was used.

How it was maintained is equally important. A 20 year old engine with 150k miles on it that was well maintained and not thrashed should not need a rebuild. A 20 year old engine with 150k miles on it with a spotty service history may very well need to be rebuilt. A 5 year old engine with a blower running high compression and 2000 miles of hard drag racing will probably need a rebuild.

 

[bruceb]

A lot depends on age and mileage on the motor. If you are at or over 100K miles, it may pay to do a full rebuild and be good for another 100K or so. Plus you will end up with better reliability as all the problem parts would be changed, like bearings, water & oil pump. And you car will feel like new, since as it ages, it does lose some horsepower.

 

[Pacfanweb]

How it was maintained is equally important. A 20 year old engine with 150k miles on it that was well maintained and not thrashed should not need a rebuild. A 20 year old engine with 150k miles on it with a spotty service history may very well need to be rebuilt.

Correct on both counts, and I never said different.

What I DID say was, most shops WILL recommend rebuilding/replacing an engine that old with that much mileage, regardless. Simply a C.Y.A. recommendation. That is a fact.

 

[SooperDave]

If it needs a valve job and it's a V8 it's just a matter of taking off the other cylinder head and doing the valve job on both heads at the same time. Removing the cylinder heads is not going to cause other things to break and as long as the engine has been well maintained there is no reason to assume that working on it will cause other issues or bring to light other issues.

I wouldn't advise someone to just ignore a cylinder head gasket leak but at the same time I wouldn't be recommending a complete engine rebuild either.

Just out of curiousity, how many miles are on this engine anyway?

In your own words complete and utter nonsense. You do a valve job on a high mileage engine you raise the compression ratio. Not to long after a rod knock, excessive blow by, or timing chain slap can follow. And I have seen every one of these issues more than once from just that. Hows that for other issues coming to light?

 

[JulesMaximus]

In your own words complete and utter nonsense. You do a valve job on a high mileage engine you raise the compression ratio. Not to long after a rod knock, excessive blow by, or timing chain slap can follow. And I have seen every one of these issues more than once from just that. Hows that for other issues coming to light?

Right, I recommend he restore the entire car...it's the only way to be sure.

I've had a head gasket fail on a few older high mileage cars. Nobody EVER recommended I rebuild the entire engine.

 

[SooperDave]

Right, I recommend he restore the entire car...it's the only way to be sure.

I've had a head gasket fail on a few older high mileage cars. Nobody EVER recommended I rebuild the entire engine.

Cool story. The fact is you said it will not bring other issues to light and you are flat wrong.

 

[JulesMaximus]

Cool story. The fact is you said it will not bring other issues to light and you are flat wrong.

I said, not if it was in good condition otherwise. Just the fact that it's old and needs a headgasket is no reason to believe that doing anything other than replacing the headgasket is needed.

 

[SooperDave]

I said, not if it was in good condition otherwise. Just the fact that it's old and needs a headgasket is no reason to believe that doing anything other than replacing the headgasket is needed.

You did not. No where in this post does it say that:

Complete and utter nonsense. Once the head is off he can check to see if he thinks it needs a valve job or resurfacing, he can also see if there is coolant in the engine before he even starts to disassemble it by checking the oil. If it needs a valve job and it's a V8 it's just a matter of taking off the other cylinder head and doing the valve job on both heads at the same time. Removing the cylinder heads is not going to cause other things to break and as long as the engine has been well maintained there is no reason to assume that working on it will cause other issues or bring to light other issues.

I wouldn't advise someone to just ignore a cylinder head gasket leak but at the same time I wouldn't be recommending a complete engine rebuild either.

Just out of curiousity, how many miles are on this engine anyway?

Well maintained does not mean it does not have worn out parts. You know, like bearings and valve guides and seats and rings and timing components. And a valve job certainly can bring those issues to light. You are wrong.

 

[JulesMaximus]

You did not. No where in this post does it say that:


Well maintained does not mean it does not have worn out parts. You know, like bearings and valve guides and seats and rings and timing components. And a valve job certainly can bring those issues to light. You are wrong.

You don't find out about worn main bearing by pulling a cylinder head off and a simple compression check will tell you if the rings are worn and need to be replaced...

Obviously, if he has blue smoke coming out of the tailpipe and low compression in addition to the head gasket problem then he would definitely need an engine rebuild.