Engine/Transmission (1994 - 1998) head gasket coolant leak

[BLeinart]

I'm new to this forum, just signed up. I got a 95 cummins and I started smelling coolant. Found a wet spot just below thermostat housing at the head gasket. Is this a common problem. What should I do. Thought I might be lucky with new thermostat gasket, but it looks like the head gasket.

 

[hsmith]

Yep, head gasket time. Many threads on this problem.

 

[KCanepari]

My '96 has leaked there for a long time, I just thought it was the thermostat housing leaking.

 

[BLeinart]

are there any after market gaskets that are better than cummins? I read someone talking about installing o rings, but I'm not sure what they were talking about.

 

[BLeinart]

I was also wondering if there is anything else I need to do while I got the head off. I was planning on adding some power, so now would be a good time to prepare for that.

 

[WDimig]

if you opt to do the head gasket yourself, i would reccomend that you have the head resurfaced, and thoroughly check the deck of the block, i just put a engine in a armored truck that has a ISB engine, and the gasket was blown very badly in that area, after removing the head, further inspection showed that the coolant had been leaking for so long that it had erroded a path between the coolant jacket in the block, and the outermost head bolt hole next to that passage, and the same etching was present in the head. soooo my point is, check check check eveything, if the block is out of spec, it needs to be removed to redeck the surface. good luck with your repair if you decide to do it.



wes

 

[Joseph Donnelly]

The replacement Cummins gasket is better than the original, 3283335 (-37 is . 010 thicker; -39 is . 020 thicker). Check surfaces for flatness, get them really clean. If the head is warped or eroded at the cylinder sealing rings, get it surfaced to no rougher than 60 micro-inches, equivalent to stock. You won't be able to catch a fingernail in the "scratches. "

 

[BLeinart]

How about the cosmetic gasket vs the cummins replacement, is it a better gasket. How thick is the cummins replacement(3283335)

 

[WDimig]

from what ive read, they still have having trouble getting the cometic MLS to seal, even with both deck surfaces completely flat, the cummins head gasket is very forgiving, espescially if the block is not exactly "flat", i would reccomend looking into having the head oringed, or do a fire ring setup, the principal behind the two if the same, the oring use a stock gasket, and seals against the stock crush rings to improve the combustion seal, orings can hold boost pressures up around 70 psi, while the fire ring setup is a bit different, still uses a cummins gasket, but the gasket has had the stock crush rings lazerly cut out to accept new SS fire rings that seal directly between the head, and the block, this method when done right, makes a very strong seal, and can hold boost pressures in excess of 80+, either way you go, you will have a better seal then a stock gasket. i would also reccomend a set of ARP studs, if you do orings, and highly reccomend if you do fire rings. hope this helps.



wes



edt - as joe said the 3283335 is the new stock thickness replacement gasket, 3283337 is a . 10 over thickness gakset, and 3283339 is a . 20 over gasket.

 

[Ram-Man Cummins]

Head Gasket Just replaced.

I just replaced my head gasket with a new Cummins . 20 over gasket and I had the head milled smooth with a shine. The best upgrade was the ARP head stud kit.

Get a stud kit if you decide to replace your head, ARP makes a good kit and follow the directions exactly. The stock head bolts are lame and will stretch bad. I stretched 4 stock bolts past there spec. in one year. The stud kit with a Cummins head gasket will hold up to alot of boost, up to 60lbs.

Make sure everything is straight and perfectly clean especially the head bolt thread cavities in the block. If they are not cleaned good then you will not be able to torque the head properly.

It is a good time to replace your tappet cover gasket if you can pull your fuel pump also.

Good luck.

 

[BLeinart]

Will I be able to get the head back on on with the motor in the truck when using the studs?

 

[Vaughn MacKenzie]

Yes you can. Above the back of the engine there are two plugs in the cowl you can remove which gives you room to maneuver and drop the studs into place back there. The studs screw in with an allen key in the top. I strongly recommend going down the holes with a tap to clean them up after you remove the gunk and grime. I skipped that step on my '96 and wished I hadn't. But be careful to not remove thread material in the block. . . you can pull the stud out of the block when torquing down the nut and you'll have a problem on your hands.

Unless you're going for a lot of HP/boost you should be fine with the new gasket and studs. Milling the head is a must because 12V heads are always warped when removed.

I would run the . 010" over HG, with the . 020" you start running into exhaust hazing and harder starting in cold weather due to reduced compression. . . that HG is better for twins/high HP. By the way, you can run the stock thickness HG after milling the head too if you wanted, still plenty of room for valve-to-piston clearance and of course milling the head does not increase compression like on a gas engine. Get a valve job done while you're at it if you're over 150-200k miles.