Blown Head Gasket = Cracked Or Warped Head?!?

[Bigg-Beat-Elite]

I just brought my 97' V6 into an auto shop for a motor swap with a 95'

After a little extra work and a lot of an extra shop charges, it's now been discovered that the 95' has a blown head gasket. (Something the Craigslist seller didn't mention when he sold it).

But the mechanic at the shop is trying to tell me that part of a repair will require having the head/s machined.

A blown head gasket is fairly common with these Mustangs unfortunately, I understand that. But how likely are the heads to be cracked or warped?

I appreciate any time given to my question and thanks in advance.

 

[robertsa]

Almost definitely.

 

[wmburns]

+1. Why? Because almost no one stops using the motor when the problem first appears. They run it until it won't run any more. Which means when the motor over heats. The results of over heating is far too often cracked or warped heads.

What I'm having a hard time wrapping my head around is why a compression test and/or a cylinder leak down test wasn't done on the motor while it was still on the engine stand. Especially since this problem is sooooooooo common.

Here's the other problem as I see it. IF you were doing the work your self you might decide to roll the dice and do the work without machining the heads. After all. Your labor is free. However I don't think you make that some decision when paying someone else to do the work.

 

[Nemethjames1]

I've replaced hundreds of head gaskets over the last 20 years, and MORE times than not, the head would be just fine after cleaned up and new gaskets installed.

I would say pull head and clean the mating surface, use a straight edge and even a feeler gauge and see if it is warped anywhere.

I would be one to bet that cleaning and gaskets is all it needs, check cooking system for leaks and always replace the thermostat after replacing head gaskets just for 10$ insurance!

 

[Nemethjames1]

Shops are going to push you to have the head sent to the machine shop, mostly because it is a good thing to do if you have the money and its is just one more thing to protect us from having to warranty any labor

Plus it looks really nice having the head clean as can be! A good machine shop will clean the head really good!

 

[Nemethjames1]

Shops are going to push you to have the head sent to the machine shop, mostly because it is a good thing to do if you have the money and its is just one more thing to protect us from having to warranty any labor

 

[robertsa]

I've replaced hundreds of head gaskets over the last 20 years, and MORE times than not, the head would be just fine after cleaned up and new gaskets installed.

I would say pull head and clean the mating surface, use a straight edge and even a feeler gauge and see if it is warped anywhere.

I would be one to bet that cleaning and gaskets is all it needs, check cooking system for leaks and always replace the thermostat after replacing head gaskets just for 10$ insurance!

Please don't think I'm questioning your experience, but what is the ratio of iron to aluminum heads out of the hundreds of head gaskets you've replaced over the last 20 years? In my experience, aluminum is much more prone to warping than iron.

 

[Bigg-Beat-Elite]

Please don't think I'm questioning your experience, but what is the ratio of iron to aluminum heads out of the hundreds of head gaskets you've replaced over the last 20 years? In my experience, aluminum is much more prone to warping than iron.

The aluminum to iron ratio is certainly a valid question in terms of experience, but of course aluminum heads (which my Mustang has) are much prone to warping under extreme heat opposed to iron heads.

 

[Saberstang]

If you keep running a vehicle with a blown head gasket if it overheats you will damage your cylinder heads. More time than not you will have to purchase new cylinder heads than being able to rebuild your cylinder heads. If your vehicle has a blown head gasket stop driving it until you can repair it because you will cause more damage to your engine.

 

[Neuron]

A clean up surface or fixing a warpage problem, which is it?

 

[Mattstang04]

It's a big enough project to warrant pulling out all the stops. Check everything so you don't get burned after putting it back together. Just on the off chance, do everything the first time to ensure you don't have to do it a second time.

 

[Nemethjames1]

Robertsa, clearly aluminum heads warp easier. But more times than not they are good to go. Put a straight edge on it and if straight clean it and install. Doesn't take long to inspect, or pay a professional won't cost much but I would bet they are just fine. Just the way the ratio always works out