First Diesel 1998 C3500 6.5

[Sramos03]

I recently purchased my first diesel truck a 1998 C3500 with the 6.5. The guy that sold it to me told me it was going through colant and that he noticed the oil pressure read 0psi so decided to park it and not move it. He gave me a really good deal and since it has a tool bed I wanted to get it running to do some landscaping jobs on the side. It has been leaking oil tried to start it and sparked but just fluttered. The batter that I had bought was dead the next day. I’m still learning about trucks so my knowledge is limited. I included some pictures, any help or guidance would be greatly appreciate as always.

 

[smdk2500]

The oil leaks could be alot of things. I would suggest that cleaning the engine off with degreaser and see where it is coming from. Looking at the pictures to looks like you could have a front main leak or possible oil pan leak. It also looks like the oil cooler lines are leaking. Those are a known problem on most GM trucks of this era. There are company's that make braided lines with correct fittings for the block and cooler.

As for the overheating issue. These engines are known for blowing head gaskets cracking heads, breaking cranks and main web cracks.

That truck should have 2 batteries not one. The starter needs all to juice it can get to crank the engine over.

The 0 psi oil pressure could be a bad sensor. Again known for being not very reliable.

How long has the truck been sitting? What shape is the fuel filter in? Is it full of algae or just plugged? Does the lift pump work? Do not use starting fluid on it. If you use it to often the engine could become additited to it and will need it every time you start it. It is also hard on rods and prechambers. Ive seen pictures of heads that have the prechambers blown out due to starting fluid usage.

After you get it running just remember that there are limitations to it. It is not going to be as powerful and any of the next diesels that came after it. It is not going to be a power house and will require a small fortune to get it close to what a 1st gen dmax is. And then it might not even be close.

Here are a couple links that might help you out with your truck.
This one is just a basically a walk through with quite a bit of good info.

Info: - 6.5 NEWBIES - **START HERE**

Be advised, this is a VERY long post (split into two), but contains information some of the more commonly asked information that’s helpful to the new (or prospective new) 6.5 owner. Reading this post (as well as the other posts marked “New Members Read This” in the 6.5 forum at the beginning...

www.dieselplace.com

This one is for the forum itself. There are alot of good knowledgeable
people there.

6.5L Diesel Engine

Discuss the 6.5 GM diesel engine & all associated components.

www.dieselplace.com

 

[Sramos03]

The oil leaks could be alot of things. I would suggest that cleaning the engine off with degreaser and see where it is coming from. Looking at the pictures to looks like you could have a front main leak or possible oil pan leak. It also looks like the oil cooler lines are leaking. Those are a known problem on most GM trucks of this era. There are company's that make braided lines with correct fittings for the block and cooler.

As for the overheating issue. These engines are known for blowing head gaskets cracking heads, breaking cranks and main web cracks.

That truck should have 2 batteries not one. The starter needs all to juice it can get to crank the engine over.

The 0 psi oil pressure could be a bad sensor. Again known for being not very reliable.

How long has the truck been sitting? What shape is the fuel filter in? Is it full of algae or just plugged? Does the lift pump work? Do not use starting fluid on it. If you use it to often the engine could become additited to it and will need it every time you start it. It is also hard on rods and prechambers. Ive seen pictures of heads that have the prechambers blown out due to starting fluid usage.

After you get it running just remember that there are limitations to it. It is not going to be as powerful and any of the next diesels that came after it. It is not going to be a power house and will require a small fortune to get it close to what a 1st gen dmax is. And then it might not even be close.

Here are a couple links that might help you out with your truck.
This one is just a basically a walk through with quite a bit of good info.

Info: - 6.5 NEWBIES - **START HERE**

Be advised, this is a VERY long post (split into two), but contains information some of the more commonly asked information that’s helpful to the new (or prospective new) 6.5 owner. Reading this post (as well as the other posts marked “New Members Read This” in the 6.5 forum at the beginning...

www.dieselplace.com

This one is for the forum itself. There are alot of good knowledgeable
people there.

6.5L Diesel Engine

Discuss the 6.5 GM diesel engine & all associated components.

www.dieselplace.com

Thank you for the information I really appreciate it. The guy was using the truck as his daily until October so it has been sitting since then. I have around 1K saved up to try to get it running. Would it be better to have it rebuilt or try to invest in a different engine. Thanks again.

 

[618 Syndicate]

Why do you want a diesel? A 6.5 sucks at doing what most people want a diesel for, because it's not particularly powerful or fuel efficient.
With common upgrades it can be made reliable and "better" but even then as noted above, you're still not in Duramax territory. Cummins or Powerstroke either.
I've owned 2 of these boat anchors, there will not be a 3rd.

 

[618 Syndicate]

I should also note that these motors have their place, and a (small) number of fans. Light duty slow towing is what they're "good" at, and then only after known issues have been addressed. Even their most dedicated fans will admit this.

 

[Z71Hobbs]

Why do you want a diesel? A 6.5 sucks at doing what most people want a diesel for, because it's not particularly powerful or fuel efficient.
With common upgrades it can be made reliable and "better" but even then as noted above, you're still not in Duramax territory. Cummins or Powerstroke either.
I've owned 2 of these boat anchors, there will not be a 3rd.

I’ll agree and disagree. They are quite affordable, and with around 400ftlbs of torque, they can do quite a bit. Now that said, they don’t do anything quickly. But they can be found for a fraction of a price of the duramax trucks and other equivalents.

Unfortunately, most people didn’t do basic maintenance- you’d be amazing how many people wouldn’t change oil at a 3-5k interval, and injectors and glow plugs pretty much never got changed.

Edit. 618’s next post summed it up!

 

[Z71Hobbs]

Thank you for the information I really appreciate it. The guy was using the truck as his daily until October so it has been sitting since then. I have around 1K saved up to try to get it running. Would it be better to have it rebuilt or try to invest in a different engine. Thanks again.

If it’s going though coolant, you really need to look at your engine oil. You might be doing more harm than good if you have a head gasket issue.

 

[smdk2500]

I agree with Z71 hobbs. I should have stated in my first post I would find where the coolant is going first before dumping any more money in it then needed. If you do have a head gasket that is blown I would almost put money on there being at least one cracked head. Last I knew the heads are in the 6-800 dollar range apiece for quality heads from reputable sources. Having it rebuilt or sourcing a different engine is a hard call with it not being my check book. I have heard it runs almost as much to rebuild one then it is to get a new optimiser. I could be wrong on that I don't know I haven't went down that road. When mine goes I don't think I will replace it. I will more then likely part the truck out. But who knows I might fix it. Time will tell.

 

[618 Syndicate]

The head gasket/cracked head is what soured me on these motors. 6.2 heads went on a 6.5 turbo'd block. Newer turbo, new crossover pipe, new glow plugs/relay and down the road she went. Cool looking truck, but I do NOT miss it.

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[Jonathanhicks]

The head gasket/cracked head is what soured me on these motors. 6.2 heads went on a 6.5 turbo'd block. Newer turbo, new crossover pipe, new glow plugs/relay and down the road she went. Cool looking truck, but I do NOT miss it.

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That is sharp truck