Changed every cooling system component - Jeep still overheats

ramathorn said:

After replacing every cooling system component, I did a block test with the engine HOT and the cooling system tested positive for exhaust gases (head gasket/cracked block). This is number 11 on old_man's list. See my picture below for how the fluid is no longer blue but has turned yellow. I would pay to have the block checked before going too much further.

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Yes sir, thanks to Old_Man and your post, I've done some research and ordered a kit. Going to perform this test this week and pray to the Jeep Gods that the liquid stays blue.

I already changed the head gasket once last year, I'm hoping everything was put together back correctly and I don't have a leak again.

Old_Man's head gasket rule. Always spray the head gasket with CopperKote before assembly. Been doing it for 50 years.

GreatOdin'sRaven said:

1. Buy better parts ($300 radiator instead of a $100 radiator)
2. Run distilled water/Water Wetter until winter time and then swap back to antifreeze 50/50

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FWIW, I found and installed the Mopar Max Cooling radiator (available if you are running a manual transmission) and have had great temps since, even w/ our 105 degree days. This after having problems overheating when its this hot and climbing hills. Now, that may also be the effect of a new radiator absent of any crusting up internally. Just mention this to echo that the OEM radiator is a good one.

GreatOdin'sRaven said:

Going to perform this test this week and pray to the Jeep Gods that the liquid stays blue.

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It will be nice to have the kit on hand for the future just in case. I want to make it super clear though, my vehicle PASSED the test when it was operating at lower temperature. It was not until I got the vehicle at overheating temperature that the test failed. This was very tricky to do because the boiling water can bubble out of the radiator cap area and onto your hands or worse. The radiator must be at least half empty or else you'll be sucking coolant into the tool instead of air.

I would have the largest safety glasses on that you own, as well as a cold hose or bucket to douse yourself in case you can scalded.

This is annoying to do but it seems to be the only way to properly test for the "head lifting off block at temp" problem. I'd be very curious to know if others have ideas.

Another possibility is to get the engine really hot and then pull all the plugs really fast and do a compression test but that still takes time to set up so by the time you test compression the engine may pass the test like normal.

ramathorn said:

It was not until I got the vehicle at overheating temperature that the test failed.

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Very interesting! I will obviously perform the test first at lower temps and see if I can get it to fail.

If not... Then I'll continue to attempt as temperature rises, thanks for the tip! I would have cashed out once it passed at low temps.

I have a bluetooth OBD Sensor where I can monitor the coolant temps on my phone while I perform the test. Things get interesting around 170 with the cap off, I suspect I'll have more time with coolant half empty.


I'll update as soon as I'm able to do this test.

A tip on installing head gaskets. Here's what I do re-installing a head after pulling the head, pressure testing it , and resurfacing it:
1. Gently scrape the block and head surfaces, then clean the surfaces with lacquer thinner and clean paper towels.
2. Keep cleaning both surfaces until you can wipe the surfaces with a lacquer thinner soaked clean paper towel and the towel STAYS CLEAN.
3. Coat the block and head surfaces with about three(3) coats of aluminum paint, i.e. the type aluminum paint that is sold for use on metal stove chimnies.
4. Also coat the gasket with aluminum paint as well.
5. Bolt the head/gasket on by incrementally increasing the torque. If a straight six, one of the front head bolts is at a lower torque than the rest of the head bolts. Check your manual to ID that head bolt.
6. Fire the engine up and warm-up to operating temperature and shut down.
7. Retorque the head, run it a week and retorque it again and maybe one more time. Keep re-torquing the head until the torque does not change after cool downs.The re-torquing is REQUIRED because the head gasket/aluminum paint is compressing down and the torque is being reduced. Likewise, the head bolts are resettling because of sealant softening on the bolt threads.

This is an "olde hot rodder's/racing trick" that works. Years ago many gaskets were aluminum paint coated. The aluminum paint fills/seals the metal surface pores but also allows the head to expand and contract WITHOUT tearing the gasket. Coating a gasket with teflon and assuming it will expand and contract without the teflon "digging in" and tearing is wishful thinking. Thermal expansions, in heads, are typically large expansions and large expansions/contractions can tear gaskets or teflon coatings. In my view, those gaskets sold to be torqued once and forgotten about -are a joke. Hope this helps!

Best regards,

CJR

Well, my nightmare is confirmed. Took about 5 min. But the liquid turned green.

Thanks for all the help guys. I probably would have never found this.

Looks like I have a nice weekend project ahead of me.

Anyone care to point me in the direction of a quality gasket kit?

Possibly a head gasket write up? It’s been awhile since I’ve done this.




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Your welcome.

I run the Mopar 043 performance metal head gasket with Copper Kote in my stroker and it has 200k+ miles.

https://www.amazon.com/401612-Copper-Coat-Aerosol-Wt/dp/B000M8NZ8E

Another thing to consider are the head bolts. Years ago when head bolts were torqued, the bolt material stretched elastically but did not yield because the bolt metal's yield stress was much higher than the stress induced by the torque. In other words, the bolt stretched but did not yield and the bolt clamping force remained constant. Those head bolts could be used again and again. When the torque was removed from this type of head bolt, the bolt would return to its original length.

It is my understanding, that somewhere in time the Jeep head bolts were changed to "yield at the applied torque". With these bolts, when the torque was removed the bolt did not go back to its original length but was slightly longer. Fel Pro recommends only using Jeep head bolts once. That means you'll need to replace the head bolts or find an ARP replacement bolt set that doesn't yield at the applied torque/temperature and can be reused again.

Best regards,

CJR

GreatOdin'sRaven said:

Well, my nightmare is confirmed. Took about 5 min. But the liquid turned green.

Anyone care to point me in the direction of a quality gasket kit?

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It is a disappointment yes BUT, this is one of the easiest head gaskets to replace. One cylinder head, no overhead cam, iron block and head, good stuff!

I'll be replacing mine as well. Below is my list of parts from Rockauto. This includes a new serp belt and belt tension measuring tool (cheap and helpful). New gromets for the PCV valve, and the valve itself. The gasket kit includes more gaskets that you'll actually need.

Other items not on this that you might need:
-Header. If it is cracked (mine is, good time to replace)
-Torque wrench (20-110 lb-ft)
-Spark plugs
-ECT sensor
-Coolant
-Thread sealant for front head bolt (white tube at parts store)
-Shop towels to stuff in the cylinders while cleaning
-12 pt. 1/2" drive socket for the head bolts (I don't know the size though)
-Include space in the budget to have the head professionally gone through/resurfaced

GreatOdin'sRaven said:

Well, my nightmare is confirmed. Took about 5 min. But the liquid turned green.

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Ouch. Hopefully, it's just the gasket.

Make sure and check the valve stem clearance. They tend to wear. NEVER allow a machine shop to knurl the valve guides as a fix. It doesn't cost that much to have them reamed and sleeved. That way they are good for 200k+ instead of 10k.

If you pull the head, change the valve seals.

While you have the head off, have it tanked and the freeze plugs replaced. A few bucks spent doing these preventative measures will yield a head that you can count on for years. Nothing worse than doing a head and next year having to pull it for smoking or leaking.

Thanks for all the tips.

I also have a lifter tick, so it will be a good time to swap the lifters out too.

The sound went away when a put a bottle of engine restore. but came back a few weeks later.

-SL

Before blindly replacing lifters, take a look at the old ones. Make sure the face is not scored in any way and that the face is flat and that they slide smoothly in the bores. If not, only replace the cam and lifters together.

Make sure and run ZDDP during break in at least, if not full time. Go through a break in period just like you would with a new cam/lifters.

Personally, I would flat lap the face with oil and 400 grit, disassemble and completely clean, then put them back in the same holes. Make sure and flush the push rods.