• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

Second go Around

NVW

Well-Known Member
Messages
9,012
Reaction score
2,145
Location
Castor, AB.
My 95 K3500 was rebuilt 3 years ago, after about each and every month I would have to add a bit of coolant. There was a slight vapor under the oil fill cap. Then the WP gasket let go and I fixed that thinking my problem was fixed. No go. I thought maybe the head studs had a poor seal but I could put 16 psi to the cooling system with my Mighty Vac and 24 hrs later it would be at 15 psi.

Last summer I used pure water and the leak stopped, I know antifreeze will leak where water won't, then I switched back to a mixture and the coolant loss reappeared.

This winter I was using RO water from town which uses Chloramine instead of Chlorine for water treatment. Some say it eats chrome fixtures. Anyway it has since developed an extreme dump of coolant into the oil.

I had suspected the head studs but am at a loss on the pressure tests, I even did one with the engine at operating temp and had the same results.

I'm thinking there is a crack in a head intake runner/coolant passage, or the head studs that let coolant through under expansion due to heat. The Chloramine may have eaten out the Locktite on the threads.

Oh, 4 cylinders compression tests at 380+ psi and 4 test at 400+. Not a head gasket IMO. No hard coolant upper hose.

BTW the engine is on it's way out for an inspection and bearings.
 
Last edited:

WarWagon

Well it hits on 7 of 8...
Messages
9,352
Reaction score
4,806
Location
AZ
Rebuild the turbo as well from the coolant contaminated oil. And oil pump... Donno why, but, I have run into places not replacing the oil pump during rebuilds and it cost me a couple months of downtime while they rebuilt the engine again.
 

NVW

Well-Known Member
Messages
9,012
Reaction score
2,145
Location
Castor, AB.
Turbo bearings seem to be OK on both sides, it's already out. valve covers are off, I was hoping to see if the head studs were washed out, just a mess under the covers.
 

WarWagon

Well it hits on 7 of 8...
Messages
9,352
Reaction score
4,806
Location
AZ
Turbo bearings seem to be OK on both sides, it's already out. valve covers are off, I was hoping to see if the head studs were washed out, just a mess under the covers.
You pressured up the cooling system with the covers off?

Have the turbo apart or just checked free play? Just saying turbo bearings get hurt the worst and first from coolant in oil. So if you are *assumed* rebuilding the engine over coolant the small extreme speed turbo bearings did worse. (Coolant is quicker at corroding and ultimately ruining bearings than the US Gov't Clunker Bomb that couldn't lock up a 6.5...) It's on record that Marvel Mystery Oil will wipe out ATT bearings. Rebuild kits are available for the ATT if that's what your are running.
 

NVW

Well-Known Member
Messages
9,012
Reaction score
2,145
Location
Castor, AB.
You pressured up the cooling system with the covers off?

Have the turbo apart or just checked free play? Just saying turbo bearings get hurt the worst and first from coolant in oil. So if you are *assumed* rebuilding the engine over coolant the small extreme speed turbo bearings did worse. (Coolant is quicker at corroding and ultimately ruining bearings than the US Gov't Clunker Bomb that couldn't lock up a 6.5...) It's on record that Marvel Mystery Oil will wipe out ATT bearings. Rebuild kits are available for the ATT if that's what your are running.
No I didn't, I still can. The coolant I use isn't as harmful as the green.
 

NVW

Well-Known Member
Messages
9,012
Reaction score
2,145
Location
Castor, AB.
Put the coolant back in and pressured to 16 psi and left it for a couple hours while visiting a friend who stopped by, no leakage visible and no pressure loss. I am going to leave it over night. It has to be the studs, they must expand at a different rate than the head castings. A gasket or a crack would leak IMO.
 

WarWagon

Well it hits on 7 of 8...
Messages
9,352
Reaction score
4,806
Location
AZ
I have had head that was cracked on a 1988 6.2 from the block heater falling out at 75 MPH... It would only leak when hot. We had to warm the engine up for 2 min with the water pump belts off and crossover off to see what side the bubbles started from. It would blow coolant out so may not apply to you.

I would put the injector lines back on with the covers off and warm the engine up. Careful from the pushrods spitting oil. I agree it's better to see where it's coming from.

It's possible the leak is in the water pump area or timing cover.
 

NVW

Well-Known Member
Messages
9,012
Reaction score
2,145
Location
Castor, AB.
Coolant has never gone out the overflow. I have an extra set of valve covers, I may cut the top off them so it doesn't puke oil all over.

The cooling system was still at 15 psi at noon today. 1 psi drop since 3:00 P.M. yesterday.

Last fall I did a hot pressure test and the psi dropped 2 or 3 psi, I can't remember exactly. The cooling of the liquid would have a pressure drop of it's own.
 

NVW

Well-Known Member
Messages
9,012
Reaction score
2,145
Location
Castor, AB.
Looks like a couple studs on each head could have been leaking. When the heads were lifted a bit of coolant dropped out of each of those head stud passages. There are also 2 other stud threads that had rust. I think those may be due to when I ran straight water.

I was tight with the thread locker when I applied it, thinking I didn't want to fight it, if and when it came apart again. When this one was using a bit of coolant, I slopped it on the next engine, no leaks on it.:) This one will get a generous amount when it goes back together.
 

Will L.

Well-Known Member
Messages
11,275
Reaction score
14,416
Location
Boulder City Nv
What do you think about the oring mod at the top of the head? This is the one issue I have any fear of when I redo my optimizer. All the other stuff just do it by the book and ya don’t have to worry. TTY known failures and proven to cause so many of the headgasket losses vs arp known leakers. Smh.

How friggin hard is it to not have wet holes in design?!? Rant not over just on hold for now...

Gonna do anything else inside this engine different while it’s apart? Gapless rings, coated bearings, etc?
 

Husker6.5

135' diagonal 16:9HD, 25KW sound!
Messages
2,460
Reaction score
2,540
Location
Lincoln, NE
Just have to brush on LOTS of Teflon sealer on those wet hole ARP studs! Seems everything is a compromise of some sort on these engines.
 

NVW

Well-Known Member
Messages
9,012
Reaction score
2,145
Location
Castor, AB.
What do you think about the oring mod at the top of the head? This is the one issue I have any fear of when I redo my optimizer. All the other stuff just do it by the book and ya don’t have to worry. TTY known failures and proven to cause so many of the headgasket losses vs arp known leakers. Smh.

How friggin hard is it to not have wet holes in design?!? Rant not over just on hold for now...

Gonna do anything else inside this engine different while it’s apart? Gapless rings, coated bearings, etc?
I don't think I'll do anything different other than be more liberal with the Blue Loctite. I only put a drop on them the first time.

This truck is only used for work anymore and doesn't see many miles.
 

WarWagon

Well it hits on 7 of 8...
Messages
9,352
Reaction score
4,806
Location
AZ
I also tighten the studs into the block by using a double-nut arrangement. This allows the lock tight to do it's job better. The risk is dimple of the block around the stud. So be careful as to how tight. I got them as tight as I could with a hand wrench. YMMV.

Yes, coat the ARP studs in lock tight like you don't want to see em again. I run them in a little, back out some and in the rest of the way to help coat everything. Seriously I used Red... They are never coming back out. :jawdrop:

The Oring to me is a waste. You don't want it to get past the block threads. If it does you already lost the battle.
 

Will L.

Well-Known Member
Messages
11,275
Reaction score
14,416
Location
Boulder City Nv
The tty bolts even use a sealer on the bolt head flange though. GM new some gets past the theads, thats why they do it.
023AE84F-E96C-4C7B-8BCA-1148D9005CAF.jpeg
That is why I’m thinkin about the oring seal idea. Just thinking how hot does the head surface get and what is that oring going to withstand.

I agree 100% seal at the threads is what is really desired. I want some crap that seals up nuclear power plant tubs, ya know? Haha
 
Top