flusher said:
I thought about cutting the wings off the petcock on my 135 and using a deep 9/16" socket. I'll do that after I try the long open end wrench approach.
No hurry on the 135 overheat problem. I'm busy with my late summer project (a Japanese garden with koi pond). I'd like to finish the pond this month. And my younger son is getting married in early Sep in Sacramento so I'm helping out with the arrangements.
Good luck finding an MF with sick engine. I'm sure they're around in your neck of the woods, judging by what I see on eBay and TractorHouse.com.
Got ambitious today. Removed the wings from the block petcock (channel locks plus metal fatigue) and used a deep 9/16" socket to unscrew the petcock from the block. No sweat, it came out with no trouble (PB Blaster may have helped).
Result: got strong flow of 50/50 coolant out of the block (about 2 quarts).
The 135 cooling system capacity is 10.5 quarts. I can get 8 quarts into and out of the radiator and now another 2+ quarts from the block. Coolant all present or accounted for.
I'm certain that the coolant came from the block and not the radiator because I drained the radiator and filled it with straight water a few days ago for the water pump test (see previous post in this thread). I got 50/50 coolant out of the block, not straight water.
Unless I'm missing something, the flow I got out of the block pretty much guarantees that there's no major problem with coolant flow through the block. Didn't know what to expect from a 43-year-old tractor, but it looks like this Perkins has had fairly good maintenance so far.
Status check:
Block coolant system seems OK.
Water pump is strong.
Getting strong air flow through the radiator.
Both thermostats (old and new) open in the 180-190F range
Radiator takes most of the flow from a garden hose OK. Note: this radiator has a plate that separates the core from the top fill so some water from the hose is bound to spill out of the top fill when you try to force full flow from the hose through the radiator.
Haven't checked for collapsed hoses yet with the engine running. I'm a little leery of working around that 135 when it's running because of concerns about the 43-year old transmission jumping into gear.
I think I'll just reinstall the old thermostat and refill the cooling system. I could use the aspirin trick to hold the thermostat open while refilling. Or I could refill the radiator, run until the thermostat opens, stop the engine and quickly add more coolant.
Once I have 10 quarts or so in the radiator/block, I'll run the engine and carefully note what's happening with the temp gauge and the radiator overflow. Hopefully I'll learn something useful this time.