300tdi cooling system pressurized.

Before I part this truck out I need some advice. Motor ran fine for 80k miles. In December I noticed the oil pressure was starting to drop on acold start ups. So I pulled the motor and found one destroyed cam bearing. New cam/bearings where installed as well as new crank bearings. Motor went back together smoothly and ran the best it ever had for two weeks and started to pressurize the cooling system. Thinking this was due to not having the head skimmed(machine shop was closed during the holidays) I pulled the head and had it surfaced new head gasket installed and all is great again for exactly another 2 weeks. Then the cooling system starting building pressure and push coolant into the expansion tank.
At this point I had to tend family matters in NY and parked the truck till I returned. While there I ordered a new AMC head from Turner another fresh Elring head gasket and new bolts. At this point thinking all is well 2 weeks to the day the cooling system is pressurized pushing coolant into the expansion tank. The block surface looks fine and was spotlessly cleaned ever time. For the hell of it I replaced the radiator with no change. Thermostat was replaced as well.

Any help would be much appreciated as I’m at the end of ideas.
 

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Napalm00

Technical Excellence Contributor
With all the work that you've done I think the only thing that could be a culprit here would be a cracked block? The real only way to tell would be to take off the head and have it magnafluxed. This can be done with the block in the truck.
 

Napalm00

Technical Excellence Contributor
Never seen that before. Ive used the large yoke electromagnet and ferrite dust to find cracks, the standard magnaflux kit.

Are you using angle torque when installing the head bolts or just ft lbs ?
 
All bolts where torqued to 40nm then 60 degrees twice and finally the ones specified went another 20 degrees.
If the block checks out crack free I’m going to try a different torque wrench and buy a digital angle gauge.
 

Napalm00

Technical Excellence Contributor
Check around the bore as well, maybe your block has been lined and it is slipping high or low.
 
Your initial problem description is throwing me off. You say that your cooling system is pressuring and pushing fluid in to your expansion tank? I'm assuming you mean that your cooling system is over-pressurizing - and pushing cooling out of the expansion tank cap?

To state the obvious, you should have pressure in your cooling system. Just trying to clarify where/what your issue is.
 
Your initial problem description is throwing me off. You say that your cooling system is pressuring and pushing fluid in to your expansion tank? I'm assuming you mean that your cooling system is over-pressurizing - and pushing cooling out of the expansion tank cap?

To state the obvious, you should have pressure in your cooling system. Just trying to clarify where/what your issue is.
Sorry for the confusion. Yes it is pushing coolant out of the expansion tank.
 
Head gasket is definitely compromised. I checked the block for warping as far as I can tell it’s flat. A .002 inch feeler gauge will not slide under the straight edge.
Still waiting on the dye penetrant to be delivered.
 

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Napalm00

Technical Excellence Contributor
If you have the coin may I suggest moving over to ARP studs and the MLS style 300 TDI gasket.

The studs you can do a much higher clamping force and if both the head and block are in good face condition the MLS will seal better. The composite gasket you are currently using is much more forgiving but, less resilient.

I'm running the Brazilian 2.8 L 300 TDI head gasket and ARP studs at 35psi boost. Works great.

The studs are expensive prob close to $500 now
 
That was the head gasket Turner recommended. I have another Elring gasket here ready to go if the block checks out crack free. I’ll put that one on for now and see what happens. If it blows again I’ll grab an mls like you suggested.
Are the ARP studs a kit or did you piece it together yourself?
 

Napalm00

Technical Excellence Contributor
I pieced it together. This was a few years ago and there are better part numbers now that require less work.


edit: im not surprised Turner recommended that gasket, its more forgiving in most cases. if you going hardcore studs and MLS is the way but, surface prep is super important
 
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I had a 300 Auto, every summer, head gasket failure. 3 heads, each one skimmed at least once, I gave up and had a second hand engine fitted.

Sadly that one suffered a runaway failure after which, being my sister's truck she stopped chucking money at it.
 
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