Lots of coolant in the VOD, Y-Pipe O-Ring is to blame?

[virtualchuck]

I was basically done with my rebuild project which has taken WAY longer than it should. (It's my first time though) Just before I finished, I just noticed lots of coolant in the VOD, even though I haven't even tried firing it yet. The first thing I noticed once I got everything back off, and got down to removing the Y pipe, is that the left O-ring was shredded into a few pieces.

I assume I did something wrong during the Y-pipe install? Does anyone have any tips to prevent a repeat of this? I did use a little red Permatex on all of the rings, I don't know if that helped, or hurt?

22296

Chuck

[Elvis]

I had a similar problem that cost me two head gaskets.


Use thread sealant when installing the 4 bolts that are holding the Y-pipe
as they are sitting in the coolant.

[virtualchuck]

I've been using liberal amounts of anti-seize on every bolt during this rebuild process, turns out a few of them should have gotten thread lock instead...

Thanks!

Chuck

[DMCMW Dave]

The bolt threads should have nothing to do with it, they are blind holes. Coolant should not be coming around the threads. If you see coolant at the bottom of the holes, someone overdrilled them at some point and now you should be using sealant.

Not sure how you would have shredded the O-ring, just be more careful re-installing it.

BTW - we always resurface the Y-pipe where the O-rings seat. Look at the surface there, it is always pitted. Sometimes a little, more often a lot. To resurface it be sure to use at least a good belt sander (we use a machine shop). They need to be flat and the two sides need to be level with each other.

[nullset]

I highly recommend pressure testing the coolant system before you finish reinstalling the manifold.

It's much easier to find that something is wrong that way, than to put it all together and start the engine, only to have to take it back apart again.

[virtualchuck]

The coolant was almost definitely coming from the left O ring side and not the bolts. I'll be sure to clean the Y pipe before I try again.

Any suggestions for treating the O-Rings? I've been using Permatex red?

I did do a pseudo pressure test to check all of the new rubber connections, but I could not find any real procedures for doing one anywhere?

Chuck

[DeLorean03]

I did do a pseudo pressure test to check all of the new rubber connections, but I could not find any real procedures for doing one anywhere?

Chuck

First, you need to get one of these:

http://www.summitracing.com/parts/snn-12270

That is just like the one I use here at the house. Then you take off the coolant bottle pressure cap and install the end of the pressure tester onto the coolant bottle. Once it's locked down, start pumping. You should hold 15-16 psi for a good 10 minutes without the pressure falling.

[DMCMW Dave]

The coolant was almost definitely coming from the left O ring side and not the bolts. I'll be sure to clean the Y pipe before I try again.

Any suggestions for treating the O-Rings? I've been using Permatex red?

I did do a pseudo pressure test to check all of the new rubber connections, but I could not find any real procedures for doing one anywhere?

Chuck

They should work dry. If you really want a sealant, "The Right Stuff" is the only RTV sealant we use on anything.

How is the surface? See photo:

Left is buffed, right is machined.

22300

[Elvis]

The bolt threads should have nothing to do with it, they are blind holes. Coolant should not be coming around the threads. If you see coolant at the bottom of the holes, someone overdrilled them at some point and now you should be using sealant.

...

Dave I saw this on 3 cars that the hole sare sitting in the coolant.
Two of these cars seemed to be original.

Strange...?!?!?

[DMCMW Dave]

Dave I saw this on 3 cars that the hole sare sitting in the coolant.
Two of these cars seemed to be original.

Strange...?!?!?

Could be manufacturing variances. But if so a bad design as you would have a leak path outside the O-ring.

[mluder]

First, you need to get one of these:

http://www.summitracing.com/parts/snn-12270

That is just like the one I use here at the house. Then you take off the coolant bottle pressure cap and install the end of the pressure tester onto the coolant bottle. Once it's locked down, start pumping. You should hold 15-16 psi for a good 10 minutes without the pressure falling.

Auto Zone will "rent" you one for as long as you need. You basically buy it for $80 and then return it for a full refund when you're done. FWIW it also comes with different size fixtures to test your cap too.

Cheers
Steven

[jawn101]

Auto Zone will "rent" you one for as long as you need. You basically buy it for $80 and then return it for a full refund when you're done. FWIW it also comes with different size fixtures to test your cap too.

Cheers
Steven

And the AutoZone tester (a MotoRad MT-300) is actually a fantastic and high quality piece of kit. I kept mine and don't regret it for a second, I use it every few months and every time I do I'm glad I have it.

[virtualchuck]

Thanks for the info guys, that is exactly what I was looking for!

Chuck

[Henrik]

I too had a problem with leaks from the Y-pipe. The problem was that a) the step around the ID of the O-ring was broken off and b) the Y-pipe's sealing surface was chipped (due to porosity). The Y pipe's chip was too large to re-surface so my solution was two-pronged:
1) Bought a new Y-pipe from DMCH and begged them to pick one that had smooth and intact sealing surfaces (my plead was effective:), it looked great)
2) I used over-sized ("fatter") O-rings. My auto parts store (O'Riley's) offers a full array of different sizes. I would think most auto parts store do.

It's been 2-3 years now and it is holding up just fine.

[virtualchuck]

I just wanted to bump this thread for one last question.

I rented a kit from Advanced Auto, which I am now reading doesn't have a compatible fitting. I guess O'Reilly's has one that does, so I will head there tonight. Right now the system is empty from changing all of the rubber hoses and cleaning the pipes. Does the system need to be full or at least partially full in order to test? Straight water okay? It sounds like it should have some liquid in it, so that it will spray out of any leaks and make it obvious where they are?

Chuck

[nullset]

I just wanted to bump this thread for one last question.

I rented a kit from Advanced Auto, which I am now reading doesn't have a compatible fitting. I guess O'Reilly's has one that does, so I will head there tonight. Right now the system is empty from changing all of the rubber hoses and cleaning the pipes. Does the system need to be full or at least partially full in order to test? Straight water okay? It sounds like it should have some liquid in it, so that it will spray out of any leaks and make it obvious where they are?

Chuck

You do the pressure test with the system completely full.

[virtualchuck]

That's what I thought, thanks!

Chuck

[DMCMW Dave]

That's what I thought, thanks!

Chuck

Water is ok for test but don't leave it in there or things will rust quickly. Coolant is better.


Sent from my iPhone using Tapatalk - now Free (http://tapatalk.com/m?id=1)

[David T]

That's what I thought, thanks!

Chuck

The system needs to be filled with liquid and water is OK but when you dump the water you can't dump it all, some remains which will dilute the antifreeze when you go to put that in. Best to do your testing with the system filled with 50/50 soft water and a premium anti-freeze like Prestone. If any leaks out during testing you just catch it and save it.

[virtualchuck]

I just found your old DMC News article Dave that talks about the procedure for flushing and adding the 50/50, that's what I'll do.

Thanks again!

Chuck

[DMCMW Dave]

Water ..........


Sent from my iPhone using Tapatalk - now Free (http://tapatalk.com/m?id=1)

Crap - phone upgrade and that signature thing got turned back on!:mad1:

[virtualchuck]

Found the problem...Hole in the cooling jacket caused most likely by a PO's attempt at replacing a broken bolt. Got an entirely new set of problems now...

22473

Chuck :mecry: