Thread repair, aluminum block

[LostinTheDesert]

I have a 2011 Dodge Journey Mainstreet with a Chrysler Pentastar 3.6 vvt V6 suffering from the Oil Filter Housing\Oil Cooler failure; iirc bad design leads to damage to oil filter housing\oil cooler due to easily overtightening the filter cap, and causing damage to the housing\cooler and leak of coolant (and maybe oil, but I'm not sure). 
My problem is in the block and bolt threads. 

Upon initially installing the new unit (fancy aluminum job, 'sposed to be better), a thread in the block would give when almost to torque. Following the recommended pattern for the 5 bolts, and tightening only handtight (in pattern) and slowly seating and snuggin' and re-checking, 1 or 2 at a time they would  strip. This is only 7 ft lbs. 

I got a helicoil repair kit for the size needed (6mm x1) and soon found out that someone else has done this before on this engine. VERY Carefully, I cleaned out the block holes, carefully re-drilled and tapped them, and using new bolts for this engine (anyone know where to find them under $10 a piece?) began again to install the part. And every time at least 1 bolt or thread\helicoiled would strip- I think the bolt because of the depth of the helicoil and the little tab you have to knock off, might have done the bolt in. 

I've read ideas about things like setting the bolts in the block and attaching nuts to their end to fix the part into place, or going a size up (which seems to be 8x1.25?) which seems like a pretty big bolt; will I have problems leaking because of torque? Does torque change when using a larger size bolt? Should I try a different type or size of thread repair and what kind? Should I use some kind of loc-tite and the same size helicoils?

Thanks in advanced. 

Edited December 27, 2022 by LostinTheDesert

[tsteves5]

I've had issues with stripped bolt holes in aluminum transmissions (specifically the transmission pan bolts) in the past and the only solution that has worked reliably for me is to re-tap the holes for a larger bolt.  At that point, using the same torque spec as the smaller bolt seems to work fine.

[John/Horace]

I agree with tsteve5 post. Drop of blue loctite is often a good idea, bigger bolt and same torque spec. When I changed my oil cooler I used a fairly new inch pound torque wrench that I knew was accurate. Don’t go to full 84 inch pounds in one step. It’s better to do it in two or three steps. Torque wrenches should be recalibrated some times.
Go to a fastener company for bolts and ask them to match the grade up in the bigger size (bring the smaller bolt). Up here we have Fastenal, Brofasco.   I doubt they are a grade 8 hardened bolt, so should be cheap. Your old bolts at 84 inch pounds shouldn’t be stretched or stripped. But it is a pain to change the cooler out,  and using larger bolts means buying new ones any way.

 

 

[John/Horace]

I guess he figured things out, or he is now stranded in the desert ….with a Journey.  Good link with pictures, torque specs of the dreaded oil cooler assembly swap.  From the Jeep people.

 

https://www.jk-forum.com/forums/jk-member-write-ups-250/3-6-oil-filter-housing-357022/