M1008 cracked head gaskets, runs fine, fix? Or engine swap?

Kishmael07

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Recently bought an M1008 that my husband and I knew little to nothing about. We just thought it was an awesome ride and loved the history behind it. It drives great and has not given any trouble. After taking it to a diesel shop he found that the head gaskets were probably cracked. However, he wanted to buy the truck (can't blame him) and he went on and on about wanting to buy it. We were not sure if the cracked head gaskets story was true or not given he was REALLY working hard wanting our truck lol welllll long story short..took it to someone else and they believe this to be true. We have the 6.2 diesel and know nothing much of diesel engines before buying this...nor are we mechanics. We are debating on whether we should we have a machine shop look into it and repair it to keep the engine original ( they believe it could be 3k to have everything fixed...which to me seems like an outrageous price) or should we do an engine swap if we are having to pay that much money? Also, does 3k seem a little steep or does that sound like a reasonable price to get in there and replace the head gaskets?

Help me!
 

NDT

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Welcome and wow that is a NICE 1008. Blown head gaskets or cracked heads typically give telltale signs such as bubbles in and overpressurization of the radiator, unexplained loss of coolant, steam in the exhaust. If you don't have these symptoms, you are good.
 

Rutjes

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Wow, great looking truck! If it's as mint as it looks in that picture I'd definitely look into fixing the engine.

You said the "head gaskets" are "cracked". Head gaskets is a pretty easy/cheap fix. If so 3k is way to much in my opinion. Or did you mean the heads themselves are cracked? Heads can be bought for 300 a piece up to 900 for stronger castings. In my opinion you really don't have to be a mechanic to work on these trucks as long as you don't have 2 left hands and have some basic tools except maybe a torque wrench. There are some very good videos on YouTube explaining how to swap heads and/or head gaskets (SixFiveTurboGarage.com).

If you really can't do it yourselves then get some more quotes from different shops and try to source the parts yourselves.
 

Kishmael07

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Wow, great looking truck! If it's as mint as it looks in that picture I'd definitely look into fixing the engine.

You said the "head gaskets" are "cracked". Head gaskets is a pretty easy/cheap fix. If so 3k is way to much in my opinion. Or did you mean the heads themselves are cracked? Heads can be bought for 300 a piece up to 900 for stronger castings. In my opinion you really don't have to be a mechanic to work on these trucks as long as you don't have 2 left hands and have some basic tools except maybe a torque wrench. There are some very good videos on YouTube explaining how to swap heads and/or head gaskets (SixFiveTurboGarage.com).

If you really can't do it yourselves then get some more quotes from different shops and try to source the parts yourselves.

Haha you can tell I am a woman with no clue as to what I am talking about. 😜 I guess the head gaskets are bad or heads are cracked? Something is wrong with it between the two. At this point it has no thermostat. When the diesel mechanic put a thermostat on something was "boiling" making him think that there was something wrong with the heads or head gaskets. The other shop that looked at it said there was something in the coolant that is supposed to help with that which made them think the person we bought it from knew and had put the substance in the coolant to help with the issue. ( Again forgive me as I am still learning) 😆 and thank you all! We will definitely look into getting quotes from other shops but unfortunately have no way of getting into the engine ourselves and doing such a task.
 

Kishmael07

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Welcome and wow that is a NICE 1008. Blown head gaskets or cracked heads typically give telltale signs such as bubbles in and overpressurization of the radiator, unexplained loss of coolant, steam in the exhaust. If you don't have these symptoms, you are good.
We haven't noticed any steam in the exhaust and the other two things we are not sure of. My husband he has been unable to find green coolant for it. Where do you buy this?
 

Jeepadict

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I love threads like this...just as many opinions as there are options and influences are only compromised by budgets. I forsee a waterfall of information in the days to come!

@Kishmael07 many techs may have only theory about a diagnosis based on observation until it comes down to actually tearing the thing apart to be able to find the definitive culprit...and then sometimes it screams in your face. My suggestion is to hold off until you can find a tech in your area that truly specializes in diesel engines specifically...finding a really good diesel tech can be very hard depending on the area, sometimes it's worth traveling for a gifted tech. In my world I value my technician friends more than any life skills counselor, hahaha!!

Sent from my SM-G970U using Tapatalk
 
Last edited:

Kishmael07

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I love threads like this...just as many opinions as there are options and influences are only compromised by budgets. I forsee a waterfall of information in the days to come!



Sent from my SM-G970U using Tapatalk
I sure hope so! I'm interested in all opinions and pros and cons of each. Also interested in learning more about my truck 😊
 

Skinny

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Big picture...

Do you like and want to keep it?

How much did you buy it for?

Getting the 6.2 repaired as long as its on the top end probably is worth salvaging even at $150 an hour shop rate.

Replacing the engine with a good reman unit could be the cost of the truck but will give you something capable of driving 250,000 miles.

Doing an engine swap gets you a lot of bonuses like power, speed, noise reduction but is going to run more then an engine replacement.

All of these are doable if you bought it right. If you paid $6k for this truck you are going to end up upside down and at a loss if you decide to bail.

Whatever you do it sounds like you should not go back to that shop or sell it to the mechanic. Your best bet if you cant fix anything yourself is to find a reputable trustworthy technician who understands old trucks.

Good luck!

Sent from my SM-T380 using Tapatalk
 

NDT

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We haven't noticed any steam in the exhaust and the other two things we are not sure of. My husband he has been unable to find green coolant for it. Where do you buy this?
Green coolant comes from auto parts store or Wal Mart or anyplace really. I would put the coolant in there and drive it around and see if you get any symptoms I mentioned. There is a product called "barrs stop leak" that your mechanic may have been talking about. It is supposed to fix slight coolant leaks.
 

DeadParrot

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No one was born knowing how to fix these things. Download the TMs and start reading. Also, a M1008 is basically a 84 Chevy K30 with a few modifications for military service, the most notable is the 24V starting system. If you need parts, that is the vehicle you ask about - an 84 K30 with a 6.2. Doesn't matter what year it was really made. The only exception would be non-stock things a previous owner added.

As for the first mechanic, the Chevy/GMC 73-87 body style has greatly increased in value in the last few years. So be wary of anyone offering to "Take a problem vehicle off your hands".

As for coolant, basic Prestone or other brand green stuff works fine. Oil is 15w-40, pick your brand.
 

Kishmael07

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Kentucky
Green coolant comes from auto parts store or Wal Mart or anyplace really. I would put the coolant in there and drive it around and see if you get any symptoms I mentioned. There is a product called "barrs stop leak" that your mechanic may have been talking about. It is supposed to fix slight coolant leaks.
Yes, it's the stop leak coolant that was found. Thanks! We will try that!
 

Kishmael07

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Big picture...

Do you like and want to keep it?

How much did you buy it for?

Getting the 6.2 repaired as long as its on the top end probably is worth salvaging even at $150 an hour shop rate.

Replacing the engine with a good reman unit could be the cost of the truck but will give you something capable of driving 250,000 miles.

Doing an engine swap gets you a lot of bonuses like power, speed, noise reduction but is going to run more then an engine replacement.

All of these are doable if you bought it right. If you paid $6k for this truck you are going to end up upside down and at a loss if you decide to bail.

Whatever you do it sounds like you should not go back to that shop or sell it to the mechanic. Your best bet if you cant fix anything yourself is to find a reputable trustworthy technician who understands old trucks.

Good luck!

Sent from my SM-T380 using Tapatalk

So if I were to say we paid 10k 😬 would you say we got ripped? This on is an 87. Now mind you, this truck has had some modifications done to it and the guy who had it before us provided receipts for 6,800 worth of work that he put into it himself. We like the truck...its slow but I don't mind that. Bought to take to car shows along side my father in laws Veteran tribute truck. I guess it was bought because it's an awesome looking truck, the fact that it's a piece of military history, and for the joy of father and son going to car shows together in their military trucks. I guess if we did get ripped as far as actual value it's worth it for the memories we hope to have with it.
 

Kishmael07

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Location
Kentucky
No one was born knowing how to fix these things. Download the TMs and start reading. Also, a M1008 is basically a 84 Chevy K30 with a few modifications for military service, the most notable is the 24V starting system. If you need parts, that is the vehicle you ask about - an 84 K30 with a 6.2. Doesn't matter what year it was really made. The only exception would be non-stock things a previous owner added.

As for the first mechanic, the Chevy/GMC 73-87 body style has greatly increased in value in the last few years. So be wary of anyone offering to "Take a problem vehicle off your hands".

As for coolant, basic Prestone or other brand green stuff works fine. Oil is 15w-40, pick your brand.

Very helpful!! Thank you!!
 

LT67

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Bowdon, GA
Recently bought an M1008 that my husband and I knew little to nothing about. We just thought it was an awesome ride and loved the history behind it. It drives great and has not given any trouble. After taking it to a diesel shop he found that the head gaskets were probably cracked. However, he wanted to buy the truck (can't blame him) and he went on and on about wanting to buy it. We were not sure if the cracked head gaskets story was true or not given he was REALLY working hard wanting our truck lol welllll long story short..took it to someone else and they believe this to be true. We have the 6.2 diesel and know nothing much of diesel engines before buying this...nor are we mechanics. We are debating on whether we should we have a machine shop look into it and repair it to keep the engine original ( they believe it could be 3k to have everything fixed...which to me seems like an outrageous price) or should we do an engine swap if we are having to pay that much money? Also, does 3k seem a little steep or does that sound like a reasonable price to get in there and replace the head gaskets?

Help me!
You should have felt a leg getting pulled when the mech said cracked head gasket.. lol
 

2INSANE

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Hello and welcome to SS! Nice ride!

My advice is... Ready?

1. Do not add stop leak into your coolant! It may stop the leak but it will also clog all the coolant passages and coolant holes on your head gasket and radiator causing overheating. I know because I have done this and seen the aftermath after taking many motors apart.

2. Diesel shops are not cheap! Most charge $120+ per hour. $3000 is about right because it is very time consuming and the heads should be resurfaced. Plus that’s about what I charge for a head gasket job ;-)

3. Do a pressure test. Is it losing coolant? White or blueish smoke from exhaust after it’s warmed up? Does it overheat?

4. FYI 95% of 6.2 and 6.5 heads crack. A lot of the time the cracks do not extend to the coolant ports on the heads. If it runs fine, drive it until it blows and get an Optimizer Longblock or drop a tbi 350 in it.
Boyce Equipment I think still sells J code 6.2 low mile motors for only $2,000.

5. A 4L80E transmission would really bring out the fuel economy in that truck of yours!Does it have a turbo?

6. I would not sell such a nice truck.
 

Kishmael07

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Kentucky
You should have felt a leg getting pulled when the mech said cracked head gasket.. lol
Haha honestly that was just me not knowing exactly what I was talking about. We took it to the guy months ago and I was trying to remember what he said about it. My husband was laughing at me tonight when I told him what I posted. Yall excuse me...🤣 I need a "truck innards" book for dummies lol I will learn though!
 

Skinny

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$10k is a lot for a CUCV. My expectation is turn key, rust free, 8 out of 10 minimum in all areas.

Fixer uppers are like $3-5 on average.

I think you are on the wrong side on the money. Just be aware that anything you spend most likely you wont be recouped selling. You also wont get any decent money with an engine problem so you are in a tough spot if it needs serious repair.

Sorry for the bad news but you overpaid at $10k if the engine has major issues.

Edit: I looked at the photo again and it looks lifted, new tires, sheetmetal is straight, interior is upgraded. Probably worth $10k without engine trouble. You may be on the edge depending on what it needs.

Sent from my SM-T380 using Tapatalk
 

Kishmael07

New member
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12
3
Location
Kentucky
Hello and welcome to SS! Nice ride!

My advice is... Ready?

1. Do not add stop leak into your coolant! It may stop the leak but it will also clog all the coolant passages and coolant holes on your head gasket and radiator causing overheating. I know because I have done this and seen the aftermath after taking many motors apart.

2. Diesel shops are not cheap! Most charge $120+ per hour. $3000 is about right because it is very time consuming and the heads should be resurfaced. Plus that’s about what I charge for a head gasket job ;-)

3. Do a pressure test. Is it losing coolant? White or blueish smoke from exhaust after it’s warmed up? Does it overheat?

4. FYI 95% of 6.2 and 6.5 heads crack. A lot of the time the cracks do not extend to the coolant ports on the heads. If it runs fine, drive it until it blows and get an Optimizer Longblock or drop a tbi 350 in it.
Boyce Equipment I think still sells J code 6.2 low mile motors for only $2,000.

5. A 4L80E transmission would really bring out the fuel economy in that truck of yours!Does it have a turbo?

6. I would not sell such a nice truck.
Very helpful! It does not have a turbo that I am aware of. I think we are going to take to to another diesel shop for a second opinion and thank you for the advice and nice words about the truck! After we get it looked at again I will probably follow up with the findings
 

Kishmael07

New member
21
12
3
Location
Kentucky
$10k is a lot for a CUCV. My expectation is turn key, rust free, 8 out of 10 minimum in all areas.

Fixer uppers are like $3-5 on average.

I think you are on the wrong side on the money. Just be aware that anything you spend most likely you wont be recouped selling. You also wont get any decent money with an engine problem so you are in a tough spot if it needs serious repair.

Sorry for the bad news but you overpaid at $10k if the engine has major issues.

Edit: I looked at the photo again and it looks lifted, new tires, sheetmetal is straight, interior is upgraded. Probably worth $10k without engine trouble. You may be on the edge depending on what it needs.

Sent from my SM-T380 using Tapatalk
Awesome! It really seems to be a turn key truck. It's actually really nice without any smoke coming from exhaust. The only person that told us that it had the problem for sure was the diesel mechanic who kept wanting to buy it. It runs like a top and starts up and drove interstate home from buying it for 3+ hours without an issue. The other shop (radiator shop) said there was the stop leak substance found which made them think possibly...going to take to another diesel shop and pray the other guy was wrong but have a feeling he was right given that a lot of these have this issue (apparently)
 
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