Two Coolant Jacket Holes

[virtualchuck]

I've been trying to track down a coolant leak into the VOD, and what I have found, is very, very depressing...

Someone must have broken an intake manifold bolt and tried to make a larger hole which pierced the coolant jacket. They then decided that one puncture wasn't enough so they decided to add a second one under the first...

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So here are my potential options:

1) Find someone that can do portable aluminum welding, fill the hole(s) try and tap a new one.

2) New cylinder head assembly

3) Lawn Ornament

Anyone have any other thoughts???

Chuck

[DMC5180]

Head has to come-off no matter what you choose. You might send it too DPI and MAYBE it could be repaired. Otherwise it's find a USED head time. Which side is it?

[Jason]

You might want to try tapping the holes and threading in aluminum plugs like I did here on my engine block.

http://dmctalk.org/showthread.php?8061-Block-coolant-leak&p=119735&viewfull=1#post119735

1000 miles and so far its holding.

You could then drill and tap the plug for the intake manifold bolt hole.

A lot less work than pulling the head. And if it doesn't work you're no worse off than before.

[virtualchuck]

Josh from DPI actually took the time to contact me after seeing the photos. I think you're right it's got to come off regardless of the solution. I like the plug idea, I'm just wondering how tough it is to tap a new hole after that?

Chuck

[AdmiralSenn]

Oh, no. I had a similar problem on my car last year (mine was my own fault, broke a tap off in the same hole).

I ended up taking the head to a local cylinder head machine shop/performance house and they welded in new material and drilled/tapped/helicoiled the hole correctly. Can't even tell anything happened.

Good luck, man.

[David T]

Oh, no. I had a similar problem on my car last year (mine was my own fault, broke a tap off in the same hole).

I ended up taking the head to a local cylinder head machine shop/performance house and they welded in new material and drilled/tapped/helicoiled the hole correctly. Can't even tell anything happened.

Good luck, man.

For a good machinist with a drill it is possible to drill and tap right on the car. If you can't get anyone to the car, removing the head is the next route. A good shop should be able to drill, tap, and insert an aluminum plug into the holes and then drill and tap a new hole for the bolt. Welding is not always the best solution because you can never get it clean enough, you never know exactly what alloy you are working with, and there is the chance of warping. Besides, that is not a minor crack, it is a big hole to fill with weld!

[virtualchuck]

My main concern, is that when you look at the main hole in photo one, you can see that it punctured through the top layer, and then it almost seems as if they hit something else underneath and started drilling into it as well. Not knowing what that second item is scares me more than anything else about using any type of patch or plug?

The head will definitely be coming off regardless, which is more than I wanted to do, but it seems to be a necessity at this point.

Chuck


For a good machinist with a drill it is possible to drill and tap right on the car. If you can't get anyone to the car, removing the head is the next route. A good shop should be able to drill, tap, and insert an aluminum plug into the holes and then drill and tap a new hole for the bolt. Welding is not always the best solution because you can never get it clean enough, you never know exactly what alloy you are working with, and there is the chance of warping. Besides, that is not a minor crack, it is a big hole to fill with weld!

[jawn101]

Oh, no. I had a similar problem on my car last year (mine was my own fault, broke a tap off in the same hole).

I ended up taking the head to a local cylinder head machine shop/performance house and they welded in new material and drilled/tapped/helicoiled the hole correctly. Can't even tell anything happened.

Good luck, man.

This is actually great to hear. I never did see (maybe my fault?) what became of your situation and I'm glad to hear it got resolved. :)

[virtualchuck]

Just an update for anyone interested. I was able to find an amazing local mechanic/engine builder that was able to repair the mangled mess and tap a hole to the proper size.

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He also suggested I use an M7 bolt with an oversized head, something similar to this I believe on the intake manifold:

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Said it would grab better, any thoughts on that?

Chuck

[DMC81]

Just an update for anyone interested. I was able to find an amazing local mechanic/engine builder that was able to repair the mangled mess and tap a hole to the proper size.

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Chuck

Thanks for the update. Glad you got it all squared away, that was a real mess you had.:thumbup:

[jawn101]

Really nice work, hope it holds as good as it looks! You can't even tell.

[Ozzie]

Good recovery!
Check that a bolt with wider head in this spot, won't have any clearance issue around the mating hole on the intake.

[virtualchuck]

Good point Ozzie. I found these expensive Chrome bolts at the local hardware store that I wanted to use if possible. But you're right it might be too snug of a fit.

Chuck

[DMCMW Dave]

Those bolts are only holding the intake on, against an O-ring seal at that, so there is not much stress involved there. I'd use the original size bolts. I can't say that I've ever seen an intake fall off an engine. . . . .

[opethmike]

Those bolts are only holding the intake on, against an O-ring seal at that, so there is not much stress involved there. I'd use the original size bolts. I can't say that I've ever seen an intake fall off an engine. . . . .

And now that you say that.....

[virtualchuck]

Those bolts are only holding the intake on, against an O-ring seal at that, so there is not much stress involved there. I'd use the original size bolts. I can't say that I've ever seen an intake fall off an engine. . . . .

I am thinking he meant that since it is a new tap, that I should use anything I could find to keep from damaging it.

He also suggested the permanent stud method, but I believe you advised against that as it would be nearly impossible to get the manifold on?

Chuck

[Nicholas R]

I am thinking he meant that since it is a new tap, that I should use anything I could find to keep from damaging it.

He also suggested the permanent stud method, but I believe you advised against that as it would be nearly impossible to get the manifold on?

Chuck

It would be nearly impossible because of the angle of the studs.

I too dont see how bigger heads keep you from damaging the threads. I would just recommend using anti-seize when re-installing new bolts.

[DMCMW Dave]

I am thinking he meant that since it is a new tap, that I should use anything I could find to keep from damaging it.

He also suggested the permanent stud method, but I believe you advised against that as it would be nearly impossible to get the manifold on?

Chuck

Due to the angle it would never work.

[virtualchuck]

She held pressure!!! 10 P.S.I. for nearly an hour...Just the slightest dribble from the newly tapped hole. Going to use some RTV and/or Teflon tape, and I think we are golden. Longest VOD job in DeLorean history will soon be completed!

Thanks everyone for the help!

Chuck

[jawn101]

She held pressure!!! 10 P.S.I. for nearly an hour...Just the slightest dribble from the newly tapped hole. Going to use some RTV and/or Teflon tape, and I think we are golden. Longest VOD job in DeLorean history will soon be completed!

Thanks everyone for the help!

Chuck

Only 10? You'll want to get 16....

Still, progress! Congrats.

[virtualchuck]

Only 10? You'll want to get 16....

Still, progress! Congrats.

I thought it was 7? Okay I'll try 16 next.

Chuck

[jawn101]

I thought it was 7? Okay I'll try 16 next.

Chuck

The coolant system runs at about 15 psi and your bottle cap will blow off at 16, so I usually test my system to 16.

[virtualchuck]

The coolant system runs at about 15 psi and your bottle cap will blow off at 16, so I usually test my system to 16.

I'm curious how long I should expect it to hold pressure, indefinitely or is it normal to lose a couple of P.S.I. over the course of thirty minutes? I've done several tests to look for leaks, everything appears dry, but I do lose the slightest bit of pressure over time.

Thanks again!

Chuck

[jawn101]

I think you should stay constant for over an hour, if not more... Last time I tested mine I had 16 psi for over 2 hours even with a slight and as yet un identified pinhole leak in the water pump somewhere (pump back or shaft seal)

[DeLorean03]

Unofficial, but 20 mins at 15-16psi is good enough for me.

[virtualchuck]

Unofficial, but 20 mins at 15-16psi is good enough for me.

After the tweaking of a couple of hose clamps, I was able to hold 15 P.S.I. for well over 30 minutes, mission accomplished!

Chuck

[jawn101]

After the tweaking of a couple of hose clamps, I was able to hold 15 P.S.I. for well over 30 minutes, mission accomplished!

Chuck

Great news! :)

[DeLorean03]

After the tweaking of a couple of hose clamps, I was able to hold 15 P.S.I. for well over 30 minutes, mission accomplished!

Chuck

Awesome :thumbup:!

[Bitsyncmaster]

I'm curious how long I should expect it to hold pressure, indefinitely or is it normal to lose a couple of P.S.I. over the course of thirty minutes? I've done several tests to look for leaks, everything appears dry, but I do lose the slightest bit of pressure over time.

Thanks again!

Chuck

That's a good question. When I tested mine after VOD work, I made up my own test gauge. It start to leak down in about 10 min. I needed to put sealer on the pipe fittings of my tester and then it would hold for an hour. So very small air leaks will show up with shorter hold times.

Hose clamps really need to tightened with a torque wrench. When I started using a torque wrench for hose clamps, I was surprised how much torque they really needed. You can not get that torque using a screwdriver.

[virtualchuck]

That's a good question. When I tested mine after VOD work, I made up my own test gauge. It start to leak down in about 10 min. I needed to put sealer on the pipe fittings of my tester and then it would hold for an hour. So very small air leaks will show up with shorter hold times.

Hose clamps really need to tightened with a torque wrench. When I started using a torque wrench for hose clamps, I was surprised how much torque they really needed. You can not get that torque using a screwdriver.

I discovered that to be the case as well. Several of the leaking connections were under the car and once I started using a (7mm?) socket instead of a screwdriver for convenience I found that giving every clamp a couple of turns stopped most of the leaks.

Chuck

[jamesrguk]

I discovered that to be the case as well. Several of the leaking connections were under the car and once I started using a (7mm?) socket instead of a screwdriver for convenience I found that giving every clamp a couple of turns stopped most of the leaks.

Chuck

100% agree with using a 7mm socket rather than screw driver, much less likely to slip and stab something too!

The quality of hose clamp also effects the amount of torque they will take, the ones with the thread cut right through the band, ironically whilst appearing weaker, often will torque up better than those with just groves cut into the surface of the band.

I understand that T-Bolt hose clamps are supposed to be very good, such as these http://www.autosiliconehoses.com/silicone-hose-shop/hose-clips-clamps/t-bolt-hose-clamps.html
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The DeLorean system has a lot of joins compared to most cars, and runs at a fair pressure with quite a significant amount of coolant so it's easy for coolant to sneak out somewhere!

J

[Bitsyncmaster]

I swear by the ABA hose clamps. Everything made of stainless (even the screw) and published torque charts.

http://www.ultimategarage.com/abaprice.html

[virtualchuck]

100% agree with using a 7mm socket rather than screw driver, much less likely to slip and stab something too!

The quality of hose clamp also effects the amount of torque they will take, the ones with the thread cut right through the band, ironically whilst appearing weaker, often will torque up better than those with just groves cut into the surface of the band.

I understand that T-Bolt hose clamps are supposed to be very good, such as these http://www.autosiliconehoses.com/silicone-hose-shop/hose-clips-clamps/t-bolt-hose-clamps.html
23027

The DeLorean system has a lot of joins compared to most cars, and runs at a fair pressure with quite a significant amount of coolant so it's easy for coolant to sneak out somewhere!

J

After noticing several old leaks/repairs, I just purchased the complete hose kit and replaced every single rubber hose. It was quite the project, but well worth it. I pulled all of the water pipes to clean and inspect them, so when I was putting everything back some of the pipes didn't quite line up so it took a couple of tries to make it fit. The clamps seemed to be okay, but they really need to be cranked since the hose is so thick.

Chuck