Blown Head Gasket

[level1]

I'm at a loss, I have a 2000 7.3 and I blew out the right side head gasket at the front of the engine last week, along with two frost plugs. We opened up the engine and couldn't find anything wrong, it didn't show signs of overheating before it happened and we were not towing, the engine looks fine. So we replaced both head gaskets. That lasted two days, last night, we blew out part of the driver side head gasket, haven't got to see if we lost any frost plugs. Was just driving on the highway, normal temps, boost etc. We're taking it apart again, any one got any ides why the engine would be doing this, could we have gotten a bad set of gaskets, we did check the torque sequence to make sure everything was correct when we put it back together the first time, so I am at a loss.

[99 7.3]

are the heads straight? just an idea

[ABOBB]

Welcome to Powerstroke.org

Dont know what to tell you about your problem.. but I'm sure there will be a tech along soon enough.

[Logan]

Originally Posted by 99 7.3

are the heads straight? just an idea

If you warped a head or the deck is not straight, it wont reseal. Also, what happend the first time it blew?

[level1]

Not sure what you mean by what happened the first time, the gasket on the right side head front bottom corner blew out, you could see it hanging out by looking at it throught the wheel well opening, so I'm guessing at the same time it pressurized the water jacket from compression and knocked out two frost plugs. We weren't towing or driving up a hill or anything like that, now after changing both head gaskets the left side head gasket blew, small piece again on the lower side, second piston from the rear. If you looked down the drivers side of the engine you can see a piece of the gasket hanging out. So not sure if the heads could be warped or even cracked as the problem has changed sides. The original side, right side is fine this time. So any ideas would help.
Thanks a bunch.

[bigcountrysg]

When you replaced the head gaskets the first time did you replace the head bolts as well. Over time the bolts stretch. Eventually they stretch enough to cause a leak. Then the leak blows the gasket when the water passing through the water jackets is underpressure.

Check the head for warppage, take it to a machine shop, have them check it for warppage and cracks. Then check the block for any warppage or cracks. If you find warppage on the block then you will need the block redecked as well. If you find warppage on the head it will need to be decked too.

When you reinstall the heads use new head bolts and torq them properly.

Do not use any loc-tite or other type of thread locker, as this may prevent you from getting the proper torq.

[level1]

Yes we did replace the head bolts, we actually went to the studs, the book calls for 95ld/ft torque, theses studs called for a 85lb/ft torque, do you think it could be to low of torque, we will check for warpage and cracks.

Thanks to all again

[bigcountrysg]

Originally Posted by level1

Yes we did replace the head bolts, we actually went to the studs, the book calls for 95ld/ft torque, theses studs called for a 85lb/ft torque, do you think it could be to low of torque, we will check for warpage and cracks.

Thanks to all again

I do believe the problem was under torqing the bolts/studs

I don't know if 95ftlbs, or 85 ftlbs is low for torqing an engine head. Should be like double or triple that. Usually when you torq down a cyliner head you do it in 3 stages. You torq down to like 40 pounds, then 80 pounds then you finish off at like 200 pounds.

I know that the numbers used in the above statement is not the correct ftlbs of torq but I was just using them to give the person an idea of properly torqing down a cylinder head.

level1 I can look in my book when I get home and let you know the proper ftlbs of torq you should be putting on those bolts/ studs.

[mech2161]

Stock Bolts

Lightly lubricate the cylinder head retaining bolt threads and flanges with clean engine oil and install the cylinder head retaining bolts.


Tighten the bolts in the sequences shown in three stages.
Stage 1: Using the first sequence, tighten the bolts to 88 Nm (65 ft. lbs.).
Stage 2: Using the first sequence, tighten the bolts to 115 Nm (85 ft. lbs.).
Stage 3: Using the second sequence, tighten the bolts to 129 Nm (95 ft. lbs.).

The torque on the ARP studs is incorrect. I torqued my H11's to 120 ft lbs.

[bigcountrysg]

Originally Posted by mech2161

Stock Bolts

Lightly lubricate the cylinder head retaining bolt threads and flanges with clean engine oil and install the cylinder head retaining bolts.


Tighten the bolts in the sequences shown in three stages.
Stage 1: Using the first sequence, tighten the bolts to 88 Nm (65 ft. lbs.).
Stage 2: Using the first sequence, tighten the bolts to 115 Nm (85 ft. lbs.).
Stage 3: Using the second sequence, tighten the bolts to 129 Nm (95 ft. lbs.).

The torque on the ARP studs is incorrect. I torqued my H11's to 120 ft lbs.

Man 95 ft pounds seems low for a diesel engine. I figured it would be at least in the 100's