mystery coolant leak - and the answer is...

[bigbillyboy]

So, I found out where the coolant is going:
[IMG][/IMG]
[IMG][/IMG]
That's what I get for hoping its just a head gasket. A pretty good little crack between the valve and the prechamber.

The other three cylinders look fantastic. So, is this head scrap metal now? Is it worth running it down to the shop for test.

If I need to replace it, what is the best one to use? my suburban is just used for commuting with the family.

The head has "ACH" cast into it. Does that mean anything?

Thanks for any and all input. I appreciate it.

Jason

[twaddle]

OUCH!!!!

Any signs of what may have caused it, radiator blockage, low coolant?

Jim

[redbird2]

clearwater cylinder heads from Clearwater FL can get new head for 325.00 plus shipping complete ready to install have been running these for several years with no problem to date have 25 or 30 sets running on truck. I noticed some one on e-bay from CA selling blanks they say new GM casting 213.00 however never dealt with them Clearwater will want your old head back they reuse the valves springs want ever they can salvage that is useable

good luck

[simon]

yea scrap allright, no need for testing

[Kennedy]

How old is the engine and what is the history on it?

The ACH tells me Alabama Cylinder Head. These would be the "new and improved" China heads. The Clearwater connection would be the same thing no?

[Robyn]

I have a set of the Clear water heads on the 94 and they seem fine although I need to be honest, they dont have a lot of miles yet.

They looked great right out of the box and the fit and finish were wonderful.
I removed two valves from each head to have a look see before I bolted them on and the valve seats and such was great looking.

Not a bad price.
$670 for a pair to my door and they sent along a prepaid ticket to get the old ones back.

These are new castings with some used parts such as valves, springs and such.
Mine looked to have all new exhaust valves as well as new keepers.

If you are planning to keep the truck I would bolt on a set and be done with it.
If one head went its a good bet the other and or gasket are close to going too.

While you have the top off its easy to do both.
Replace the rocker guide buttons too while your there.
A fresh set of injector nozzles would probably be in order to restore good power and economy while your at it.

I am completely happy with what I bought.

Robyn

[bigbillyboy]

The truck has 119K miles total and 30K on the reman REVIVA engine. I bought the truck a couple of weeks ago and so I have only put on 800 miles. Prior to pulling it down, it was one of the easiest starting, smoke free diesels I have driven. I looked for a long time to find a really nice 'burban diesel for the family. It's a little disappointing to start this way, but at least I will know for sure the top end is in good shape, and that is the typical question mark with these trucks.

As for the cause, I can't be sure, since I am pretty sure that I inherited this problem, However, the truck definitely has a new radiator and most of the hoses are new as well. Should have probably been an indication, but when I started it cold, there was no pressure in the hose, no bubbling in the coolant tank, no smoke (except for on little puff at startup), no steam from the crankcase, etc. It was about halfway home on my 800 mile drive, that I started to notice missing coolant.

How do I get in touch with clearwater?
is this the same clearwater you are talking about:
http://cgi.ebay.com/ebaymotors/GM-CH...em180131225056

once again, thanks to all for the help. I reserve the right to ask more questions as things progress....
Jason

[bigbillyboy]

The guy at the cylinder head shop (Robyn, Central Cylinder head in Portland...do you know anything about them?) suggested since they look good, and look like there is only one crack that I might consider just having them welded. What is the general opinion of a welded head? Wouldn't that be the same as "reman" head.

Just wondering, as it would be SIGNIFICANTLY cheaper.

thanks

[hayhauler69]

Here's their homepage
http://www.cylinder-heads.com/index.cfm
Looks to be same outfit on ebay

[Slim shady]

The guy at the cylinder head shop (Robyn, Central Cylinder head in Portland...do you know anything about them?) suggested since they look good, and look like there is only one crack that I might consider just having them welded. What is the general opinion of a welded head? Wouldn't that be the same as "reman" head.

Just wondering, as it would be SIGNIFICANTLY cheaper.

thanks

Contact a good machine shop they can cold weld heads by metal stitching (the process is as old as the machine repair business) Actually there is a place that sells a repair kit which I have, and use, to repair that type of crack and more. I have a set of heads that I repaired on my truck now and have not had any problems them. I repaired them because of cracks between the valves and one right through the valve seat (exhaust and intake valve). I have not had one problem yet. I doubt that they can repair a hole that is missing pieces, and welding the head would be inadvisable. The weld will crack after the first thermal cycle ( hot / cold ) if the head was not heated before the welding process and then cooled at a controlled rate after.

This is the outfit I bought my crack repair kit from http://www.locknstitch.com/ and have been very satisfied with the repairs that are possible. They have good info that you can use to make an informed decision. Good luck

[bigbillyboy]

I was on Ebay and saw this:
http://cgi.ebay.com/ebaymotors/Chevy...em120136392550
seems like a good price

then I saw this:
http://cgi.ebay.com/ebaymotors/6-5-6...em220123881753
"crack proof"!?!?! Can it be true?

I am leaning toward the Clearwater heads since I haven't read any bad things about them, but "crack proof" that seems too good be true!

thoughts? Any experinece with Proline?

[Robyn]

I have not heard all that much good about any welding on a 6.5 head.

Bite the bullet and replace the heads with a set from Clearwater.
Find them on the net.

Clearwater cyl head in a search engine will fetch them right up.

Call them on the phone.

I would not waste my money or time even thinking about welding a 6.5 head.

The castings are too thin and the ones I have seen welded broke again in short order.

DONT DO IT

I can not be more specific than that..

Big truck Cats and Cummins and detroits are a whole different bag of worms and are welded all the time with reasonable good results.

For $670 a pair to your door plus a set of gaskets is a steal.

Hope this helps.

If you want to chat about it PM me and I will give you my cell number.

Robyn

[bigbillyboy]

Thanks Robyn!

So is it safe to say that "reman" head is a head that has more than likely been welded and should be avoided?

Also,
I've heard about the different casting numbers. Are there ones i should avoid? Or does that matter with the clearwater heads?

[Robyn]

Well not always

A reman head for one of these engine thats done by anyone thats honest wont be welded.

I would only buy a set of remans from a shop I know and trust.

To be of good quality they need to be magnafluxed then if thats OK they need to be heated in very hot water and pressure tested for small leaks that the mag wont show.

The cracks between valves can be repaired by machining the water passage and pressing in a bronze sleeve.
The valve grind and such is a no brainer, just simple good tech and your good to go there.

Any head with cracks on the firedeck should be scrapped. Small cracks in the precup are ok as long as they dont cross the gasket fire ring area.

As much work as it is to do a set of heads plus new bolts and gaskets every time why mess with anything thats questionable.

Cause you know, its not going to quit in the driveway, its gonna be out in the sticks somewhere.

I M H O go with a set of fresh heads. If you want to spend the big $$$ get a fresh set of GM heads.

My money was bet on the Clearwater heads and so far so good and the reports are all good that I have heard.

I have no stake in Clearwater but they treated me good with good service and fast shipping so thats about all I can offer there.

I would however do both heads while you have the top off. Takes very little more effort once you have the intake and the lines off.

Then you can sleep nights knowing that there is not a little monster lurking under the hood waiting to jump out and bite you when you least need it..

Good luck
Keep us posted.

Robyn

[Robyn]

That ebay ad for $249 each may very well be a deal.
The fellow has 100% good feedback.
Check his shipping costs to be sure its not a ripoff.

These heads may be surplus Govmt stuff from Hummers.
Not sure.
There is so much stuff that comes up for sale thats good for cheap prices.

$249 for a new head is not at all bad.

[bigbillyboy]

That ebay ad for $249 each may very well be a deal.

These heads may be surplus Govmt stuff from Hummers.
Not sure.

$249 for a new head is not at all bad.

I assume that the government surplus hummer equipment is good, as it probably cast by AM General?

I agree with you Robyn. Really, what is a couple hundred dollars extra at this stage. It's worth a lot more than that to know the family won't get stranded! It would cost more than that in family counseling if I make the wife drive something that breaks down alongside the freeway in August

On a side note, I spoke with the warranty guy at REVIVA this morning. We had been playing phone tag for a couple of weeks, my engine is definately off warranty by 2.5 years. (30K on the complete drop in engine in 4.5 years = low yearly mileage). He spent about a 1/2 hour on the phone with me answering any and all questions about the engine in my truck. Not only that, but he was very helpful and a wealth of knowledge specific to the GM 6.5 diesels. He did verify that they use blocks and heads from AM General in their rebuilds now, but may or may not have when my engine was built. It sounds like they do alot of reman engines for dealers, and fleets, etc. He said that the best thing that happened to the cylinder heads on these engines was when AM General purchased the rights and changed the metal content of these heads.... anyway.

I guess I'll have to get replacement heads on the way soon, or plant flowers in the suburban sure would like to know if those heads on ebay for $250 are am general heads...

jason

[bigbillyboy]

So I found out that the one of the ebay sets of heads are government overstock. They are "buy it now" price of $250/each. It would seem that if they are government overstock, that they are probably genuine AM General heads. Is there any reason you can see to steer clear of these?
The dude selling them has lots of feedback and it all positive

[bigbillyboy]

So after numerous calls and photos, I bought a set off of the guy with the government surplus heads. They look to be in excellent shape, and he cut me a deal on two ($350 for both plus shipping). He was nice enough to run a straight edge along them to make sure they weren't warped. Apparently they were purchased in a lot of about 30 sets of which about half had water damage. He should be shipping them out Monday, hopefully I'll get them before the end of the week. New Felpro gaskets and stud bolts, we should be back on the road. I'll keep you posted.

thanks for all the input.