2nd Blown Headgasket

[djr99]

Recently I saw a post on an aeration leak in the head gasket which ends up pushing coolant out of the radiator into the overflow... While on a trip on Vancouver Island BC I realized that my headgasket in my 91. 5 IC'd is doing the same thing, not overheating but in general idling rough and pushing coolant out of the rad. . The oil level does not seem to be affected, which is a releif. . So I am preparing to have installed the 2ND Headgasket in 15K!! This implies to me that maybe my head was warped the first time around and never caught? The leak in the first one was exterior at #1 cyl(above stat). Boost levels are not excessive, rarely much above 30psi,the engine has about 220K on it, how much damage can be caused by running inthis condition? (I've already put on almost 600 miles already) Any Van. Islander's out there suggest a good diesel shop? I could really use some input. .

 

[dpuckett]

I ran one with a blown HG for almost 10K. Yup, you read right- 2 oil changes. Had a really hard to describe funny noise under load. got to where I couldnt Mr Magoo it anymore without making that noise. Changed HD and no more noise. Point is, unless you are getting coolant in your oil, while it is less than ideal, it should do no permanent damage.



I would definitely get the head and block checked for flatness if yours is only 15K old. You DID lube the bolt threads and shoulders, and torque, in steps in the right sequence, to 125ft-lbs, right?



Daniel

 

[MMiller]

If compression is getting out of the cylinder, it can cut a groove in the block or head, if its ran too long this way.



Did you have the head milled? The boys at PDR don't recommend putting any 5. 9 cummins head on any block with out milling the head. Even checking it really does nothing. You also have to remember you are assaulting the head gasket with roughly twice the amount of boost a stock first gen makes.



Do you let the engine come up to operating temp before running boost? This is how my second head gasket failed. Cold day, no operating temp, and 30 psi, poof went the headgasket. Less then 10 lbs of boost, until engine gets to normal operating tem.



This time, mill the head, get some new head bolts(your choice whether or not bolts), and call the boys at PDR for thier head torquing specs and pattern. Since I did it right the last time, my head gasket has been taking 32 psi, long hills, heavy loads, but my truck ALWAYS gets operating temp before applying enough boost to move the needle, especially in the winter.



Michael

 

[djr99]

I had a heavy duty diesel shop do the HG, and i would assume that they hopefully knew what they were doing, however I got the impression they didn't do too many small trucks... .

 

[djr99]

The problem has only started occuring this summer, and I usually ensure that the temp gauge has moved before putting the pedal down. . Does the head usually have to be completely dis-assembled (valves, etc) to be milled? Is it advisable to get the springs checked, and what should the spring tension be? Also what is a normal pop-off pressure for stock injectors? Also, should I have rechecked the torque on those headbolts after a certain amount of time? Thanks