Man, I've looked all over this 98's engine. I'm loosing maybe a cup every couple of days. No mixing in the oil or radiator. I crawled under and can see the dreaded green fluid collecting between the tranny and the oil pan. Right dab smack in their middle. (but basically only drops of fluid at a time) So, I looked from topside, and can see fluid nearest the #6 cylander. If I stand on a stand and look over the BHAF, I can see green on a ledge above the 4" exhaust down pipe. But nowhere can I see the actual leak...
I fear it's a head gasket. The water pump is new, maybe two months ago. I sure wish for sure that I knew where it was comming from. Any ideas?

Tom

 

Man, Hopefully it isnt a 53 block casualty, I havent heard of a 12V 53 cracking, You may be the first If it isnt that, May be a headgasket. You would be better off with the 2nd possibility.

 

My headgasket is leaking coolant externally right at the passenger side of #1 cylinder, directly under the t-stat housing. It was difficult to pin down, but I added the UV dye that can be purchased at many parts stores. All you do is add it to your radiator, bring it up to temp., then when it's dark, break out the black light and the coolant will glow. You may need to spray things down a time or two, until you locate the source of the leak. By the way, the dye is really hard to get off of skin and fabric.

 

You have a freeze plug on the back of the engine (head?), that may be the leak.

 

check this out. its a 98 12 valve

http://www.stamey.info/Truck/Cummins...NewInformation

 

might not be anything but check the water pump gasket make sure it didnt get kinked or anything never know just to be safe ya know

 

Well, a 53 block it isn't! Thank god. The problem is that without a mirror in the right spot, can't see spit. I notice that after a freeway run, THEN I can see some green. I just need a mirror to see the actual source....The leak originates above the freeze plugs. So, it's eith a block issue or a head gasket issue. One things for sure.....not good.

I'm thinking of driving north to BC and letting DAS do the work....

Tom

 

There is a large freeze plug on the very backside of the head........2-5/16" diameter or so. Mine blew completely out, but I could imagine that it could also leak. If you have a leak at the back of the engine, based on my experience, I would put money that is where it is.

Let us know what you find out.

Waylan

 

WALEXA....

Man, I hope your right! I'll check on Sunday...

Tom

 

You can reach back there and feel the freeze plug where it's depression is into the head. It is very hard to get to to change it out.......I ran across a wealth of information on TDR when mine blew out. Others have dropped the transmission to get to it. I know you don't want to do this. What I would do, although I don't normally ever recommend a fix in a bottle, is to look into that steel seal. I've read up on it and it looks like a good product. It would probably run you $90 plus shipping for 2 bottles of this product, and a couple hours time and a change of antifreeze, but it would be way less than dropping the transmission or pulling the head to address that plug. Check it out and let us know. I've read alot on head gaskets, and I can't remember ever reading where one blew at the back of the head. I would guess that surely it's happened, but I've only read about it between cylinders or at the front of the engine. Good luck and keep us posted.

Waylan

 

Sounds like the headgasket to me, especially since you said it was after a freeway run where you build more boost.

 

Jambbii,

He didn't say it originated after a highway run at high boost, he just said he notices that it leaks after a highway run. I interpret that as meaning when the engine is real good and warm. My highway running normally produces the lowest boost pressures since it is at a steady speed.

Don't get me wrong, it is possible that it could be a head gasket leak, but I just think it is more probable that the rear freeze plug could be the culprit. Until I had my incident with that rear freeze plug blowing out, I had never read anything about it. Then once it happened, I ran across a thread over on TDR where I believe Jim Fulmer had the exact same thing happen to him. Then it was like people came out of the woodwork talking about that problem. The way it was explained to me is that since the cummins is such a low rpm engine, the water pump is made for high flow at low rpm. Throw in a gsk to increase the max rpm, and I read that it can pressurize the system to 70-80 psi. Take into account the size of that plug, and I believe it was over 250 pounds of force on that large plug, whereas the smaller plugs would only have 35 pounds of force on them. This makes that plug the most prone to have problems out of. I can visualize that plug either suffering from heavy corrosion and leaking or else almost pushed out........enough to leak. It's very possible that I'm wrong though, but I would check that plug out before doing anything else based on the area that he described it is coming from. Sure be a bummer to pull the head and then find it's just the freeze plug.

One more thing, just because your oil isn't milky doesn't mean that you don't have an internal head leak. A cup every couple days or so in the oil isn't alot, and a large percentage of that should evaporate off.......at least the water portion, and the oil could still be black. Might want to take an oil sample and get oil analysis done just to be sure that you aren't slowly destroying that expensive engine.

Waylan

 

There is one other thing you might check. I chased a coolant disappearance for a while without any luck. I opened the hood right after I had driven it for quite a while and found a pin hole leak in a heater hose. It would only leak when the coolant system was under pressure and stopped within 20 seconds or so. In my instance it was squirting right onto the exhaust manifold and evaporating, so I could never see any coolant on the ground.

 

Waylan, I have had similar experiences where my headgasket leaked only after continuous highway driving. Still could be the rear freeze plug but after a sustained level of boost (unlike driving around town) a blown headgasket can rear its ugly face at you

 

A real quick look yesterday with a tiny mirror shows some white streaks that are very small, dab smack in the middle of the gasket right above the rear facing freeze plug. (behind & 6) It looks like fluid actually pools in the indentation of the freeze plug. Of course then the coolant equally flows down between the tranny and oil pan. I am really depressed. I baby this **** truck. I absolutely dog the 97 and......oh well. I will look again this afternoon to confirm.

Ok...it's confirmed. It's the head gasket. Seems like the corner. I wonder if I can just retorq the Head. I found the diagram as to the pattern, but no numbers. What do you guys think? Retorq? What are the foot pound req's?