Perforated Block??

amslube · **Posted:** Fri Feb 27, 2015 12:34 pm

I've had an external coolant leak for over a month now and HG replacement didn't fix the problem. The general area is at the rear corner passenger side. Yesterday I was determined to get some photos of the exact area thinking I had a cracked block. Pictures are pretty clear and it appears not to be cracked but a pin hole or porosity. Anyone ever see this before? Or am I the "lucky 1st" to experience this.

GreenDieselEngineering · **Joined:** Sun Jun 07, 2009 5:10 pm **Posts:** 1111

There must have been some issues with the casting in some batches. You might be able to clean and grind the area a bit and JB weld it. That is a bummer of a situation.

amslube · **Posted:** Fri Feb 27, 2015 2:13 pm

First I'm going to try a product from Blue Devil...Block and Radiator sealant. The manufacturer "Guarantees" or your money, back this will permanently fix block cracks. It's worth a try. My local NAPA didn't carry this particular Blue Devil product so I had to order it online. Should have it early next week.

If that fails, I'm going to pull the engine since this area can only be accessed by cell phone camera in the vehicle. My plan when the engine is out is to thoroughly clean the area, pressurize the block with compressed air to see the extent of the breech. If it's only a pin hole, I feel it can be drilled, tapped, and plugged. If the entire area is porous then grind the surface to roughen it up some and JB Weld it.

minisub · **Posted:** Fri Feb 27, 2015 6:40 pm

Sure looks like a crack in the first picture. Hard to say, could be my eyes, but I do seem to see it.

Been following your progress chasing this issue down. Here's hoping the block leak fixes it and you don't have to yank the engine.

Mike92104 · **Posted:** Fri Feb 27, 2015 11:58 pm

I think I see a crack as well.

amslube · **Posted:** Sun Mar 01, 2015 4:43 pm

Drained and flushed the cooling system today and added the Blue Devil Block and Radiator Sealer. This stuff was clear blue in color. No particles of any type in the liquid. Idled with the pressure cap on for about 30 minutes but didn't come up to temperature (no surprise for a diesel) so took out for about a 15 mile slow drive. No drips underneath for the initial run. The Bars Leak Tablets did the same with the initial run but started leaking again several days later. I'll know for sure how it does later in the week.

racertracer · **Posted:** Mon Mar 02, 2015 8:29 am

Look like a crack not a pin hole.

Sorry to hear.

JB weld has been used successfully on repairing hairline engine cracks...... but you need to sand and clean the area good before applying.

I would try at all costs to reach the leak without removing the engine.

Can the area be reached from below while using a lift?

amslube · **Posted:** Mon Mar 02, 2015 9:23 am

No chance at seeing if it is a crack or pinhole or repairing without removing the engine. The area needs to be thoroughly cleaned and closely inspected. Can't see the area from below or above with my eyes...had to wedge my arm in there with my phone camera after removing a bunch of obstacles. Even tried getting a rag in there to clean a bit and take more photos but no luck.

papaindigo · **Posted:** Mon Mar 02, 2015 9:49 am

If I'm not mistaken that area is immediately above the crank position sensor. If so you should not have to pull the engine to access. I think all you need to do is:
1. go thru all the steps to pull the turbo (includes removal and swinging to one side the coolant tank and maybe remove the vacuum tower that controls the turbo vanes to get better clearance) - for reinstall you will need the turbo to manifold gasket (be sure to soak the turbo to manifold nuts in PB Blaster or some such so they can be removed without breaking the studs which weak), oil feed line banjo bolt copper washers, and oil return line gasket.
2. remove the heat shield over the CPS
3. maybe remove the exhaust to EGR tube across the back of the engine.

That should give you plenty of space to view the area close up possible with the aid of a magnifying mirror and to clean the surface with like carb cleaner and grind/wire bush it with a Dremel type tool, maybe with a flexible extension.

If I am correct it's not "easy" but sure beats pulling the engine.

amslube · **Posted:** Mon Mar 02, 2015 10:46 am

I removed the coolant tank, heat shield behind the turbo, heat shield above the CPS, EGR crossover pipe, disconnected the downpipe from the turbo, and unbolted the support bracket for the CPS wire. This allowed me just enough room to get my phone camera in there and take a series of pictures by slightly changing the camera position. Took about 1 dozen or more shots before I was able to get the pics I posted. No way to see this spot with human eyes even with all that removed. Maybe if the exhaust manifold was removed it would provide a bit more room. At best it would be done blindly and not properly. Been in there a couple of times now with different access ideas, topside, from underneath, its a very tight spot. If the sealer I installed yesterday doesn't work I will certainly get in there to take another look before I pull the engine but at this point it seems to be the only option. Thanks for all the suggestions!!

amslube · **Posted:** Mon Mar 02, 2015 1:23 pm

Due to camera angle and camera position the pictures posted above make the area to appear on the passenger side of the block but it is actually at the rear. I borrowed a picture of the rear of the engine from papaindigo in the CRD Tech section. I circled the area and maybe now you can see the problem I'm having reaching/seeing the area.

flman · **Posted:** Mon Mar 02, 2015 2:00 pm

Too bad you did not know about this with the head off, it is not much of a reach, but a mirror would be good enough to patch it with some JB weld. Most likely less hours to partially pull the engine and tranny forward as a unit rather then pulling the head?

rancherman · **Posted:** Mon Mar 02, 2015 2:24 pm

Have I seen perforated blocks? Yes
On this engine? No. I've only been around VM's for a few months!

The end of the casting, right at a curve is a common spot for this, if and when it does happen!
Castings are flow through type castings. they have to be, otherwise air couldn't come out as the mold is filled, you'd have air pockets all over the place.
At JD foundry, iron would flow into an engine block casting and right out to the next mold, usually a non critical part... such as a wheel weight or suitcase weight.. when the lessor mold is filled, the iron 'backs up' and the previous mold is filled (engine block) They want the 'first out of the pig' to go on past the valuable mold, and wind up in either a sacrificial chunk of iron to be re cycled, or a less critical part. Such as a wheel weight or suitcase weight.
So as the molten iron is flowing, it might be picking up minute bits of loose casting sand.. and this is supposed to end up in the non critical mold.. No body cares if the wheel weight is porous!
in our situation, the blind corners of the mold sure could harbor this extra casting material and would make the iron porous..
Chances are there are several molds tied together in series, and yours may have been on the end of a run.. but still escaped the ultrasound inspection..
Not sayin yours is porous, or a crack. Just saying it is possible!

racertracer · **Posted:** Mon Mar 02, 2015 2:49 pm

Amsblue, I've tried K-seal on my leaky head gasket and it didn't work, it actually made it worse.

But using it on a cracked block may be another story.... Since it sealed a hairline crack on the block of a Land Rover discovery II.

geordi · **Posted:** Mon Mar 02, 2015 4:52 pm

Dang, that is a lousy location to have a leak. Based on the 3-4 people I've heard about with leaks at the back end of the block, it does seem like that area is a problem spot. Too bad it is such a cast-iron monster to get at!

Here's hoping your sealer does it, but I'd be more inclined to suggest pulling the head and just going silly with brake cleaner, shop air, and finally a fat wad of SteelStick all around that area.

If the engine was pulled, my solution might be a low voltage weld or even just brazing that entire area, and a pressurization to check it after. This sucks, I'm sorry for you.

amslube · **Posted:** Mon Mar 02, 2015 5:08 pm

Racer: I tried the K-Seal originally when I "thought" it was a head gasket. Didn't work, seemed to get a bit worse. The wife has the CRD out today so we'll see if the Blue Devil Block Sealant helps. I guessing it may take a few days so I will know by the end of the week whether or not the engine will be coming out. The Bars Leak Tabs worked temporarily. Flushed the entire cooling system yesterday to get all the residue out then installed Blue Devil.
If it continues to leak the engine's coming out. If it is a perforation or small hole I'm planning on plugging it. A crack, possible plugs as well. When I worked in an automotive machine shop when in high school, more years back than I want to admit to, I saw this done. Crack drilled at both ends to stop crack from spreading, then starting at one end tap the hole and chamfer a bit. Install plug tightly with a sealant on the threads. Grind plug almost flush with the block and peen with a hammer or needle scaler. Drill another hole along the crack overlapping the plug just installed, drill tap, install plug, and peen as before. Continue the process until the crack is filled. A company called LocknStitch makes plug kits http://www.locknstitch.com but when I saw this done plugs were made in the shop using a lathe.

I thought about pulling the head again but I don't think it any easier than pulling the engine and even then, not a lot of room to work back there. Fortunately I have a heated garage, tools, and engine lift to do this.

geordi · **Posted:** Mon Mar 02, 2015 9:03 pm

That technique is what I've heard about using on classic engines that can't be gotten anymore, but they didn't hit it after installing and used brass pipe plugs to thread into each drilled hole. Otherwise - as you describe. Seems like it might be a very slow process, but also seems that it is a successful option.

I don't know why a low-voltage (so low penetration) weld wouldn't also work to stitch over a weak spot like that, basically making a bandage of welding wire to cover the wound. As long as you didn't have the super-thin casting problem that plagued some of the (IIRC) Duramax engines, then it should be fine.

The biggest benefit in our setup is that the boom is contained by the cylinder sleeve, which is a MUCH stronger steel than the pig iron that the block is obviously cast from. The block only needs to hold the cylinders apart and keep the coolant jacket intact. Much easier to fix than a solid milled block that has to also contain the boom.

amslube · **Posted:** Tue Mar 03, 2015 5:20 pm

Wife drove the CRD yesterday about 60 miles. Coolant down about 1 pint in the coolant tank. Guess the Blue Devil product didn't work. Contacted their tech support to see it it seals over time and their reply was it should have sealed with the 45 minute idle time at the initial installation. They sent me a warranty claim form for a refund. Guess I know what I'll be doing soon...

diesellady · **Joined:** Fri Jun 08, 2007 1:06 pm **Posts:** 15

amslube wrote:

Wife drove the CRD yesterday about 60 miles. Coolant down about 1 pint in the coolant tank. Guess the Blue Devil product didn't work. Contacted their tech support to see it it seals over time and their reply was it should have sealed with the 45 minute idle time at the initial installation. They sent me a warranty claim form for a refund. Guess I know what I'll be doing soon...

I'm bringing this thread out of archive because I think I have the same problem. Did the timing belt and water pump and then ended up with a coolant leak behind the engine that I can't see. Just know it's getting worse and dumps around that same corner. Could you tell us what you found? Did you end up pulling the engine and fixing a crack/ hold in the block???
Thanks in advance for the help.

amslube · **Posted:** Wed Mar 04, 2015 2:28 pm

I didn't pull the engine yet...possibly later this week or the weekend. I'll post what I find along with pictures of the defect and if I was able to repair it and how the repair was made, or at least attempted.

Perforated Block??

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