RichardSEL
Active Member
Did the 65 mile round trip to the Merc mechanic's workshop yesterday, motorway light foot max 65mph on petrol. iCarsoft continuously connected measuring coolant temperature showing 229ºF (109.4ºC) without variation. Checked that when going up a hill and down variation + 10º max. Dash temp gauge never varied off the vertical (unless you count ½ a needle's width up then fall back)
Checked coolant gasses staying on petrol -- lots of bubbling up which changed the fluid from blue to yellow eventually. So from your info sniffer fluid will only change when subjected to combustion gasses, must assume the worst
No idea which bank (or both) has the bad head gasket -- wasn't able to do compression tests as mech is a Merc mech and backed up with work for next month and not taking in anymore non-Merc work. Still no mayo on dip stick, or coolant resovoir cap.
Collected old electric thermostat and bridge. Mech says he checked continuity and was OK. But I could'nt see how
any mechanical movement could result from heating the element so gunked the innards were with chalk . Rubber gasket had about 1" of it missing Which is how mech found it. So guess that and the leeching on the rear of bell housing hose to heater and union were doing the job of purging until such time as "Low Coolant" message came up on dash. Removal of coolant resovoir cap (on arrival after 35 miles) didn't show any coolant loss at all. 18.2mpg
Tried removing electric thermostat element and internal coil connections broke. But for those following:
No discernable indication of operating temperature marked
Some moisture noted around coolant tank cap and purge screw. Could've been not completely tightened yesterday
½ litre of water added this morning, and purge procedure as above done again
Flapping about on the interweb found:
"It cost me just under £90 to get it to the uk via amazon so the 80 degree mod is cheaper"
This is a non-electrically operated thermostat of the standard spring construction that poster says he's used on both 4.4L L322 and his V8
https://www.amazon.co.uk/dp/B00HAH8AU8/ref..._ttl_sol_0
Checked coolant gasses staying on petrol -- lots of bubbling up which changed the fluid from blue to yellow eventually. So from your info sniffer fluid will only change when subjected to combustion gasses, must assume the worst
No idea which bank (or both) has the bad head gasket -- wasn't able to do compression tests as mech is a Merc mech and backed up with work for next month and not taking in anymore non-Merc work. Still no mayo on dip stick, or coolant resovoir cap.
Collected old electric thermostat and bridge. Mech says he checked continuity and was OK. But I could'nt see how
any mechanical movement could result from heating the element so gunked the innards were with chalk . Rubber gasket had about 1" of it missing
Which is how mech found it. So guess that and the leeching on the rear of bell housing hose to heater and union were doing the job of purging until such time as "Low Coolant" message came up on dash. Removal of coolant resovoir cap (on arrival after 35 miles) didn't show any coolant loss at all. 18.2mpgTried removing electric thermostat element and internal coil connections broke. But for those following:
No discernable indication of operating temperature marked
Some moisture noted around coolant tank cap and purge screw. Could've been not completely tightened yesterday
½ litre of water added this morning, and purge procedure as above done again
Flapping about on the interweb found:
"It cost me just under £90 to get it to the uk via amazon so the 80 degree mod is cheaper"
This is a non-electrically operated thermostat of the standard spring construction that poster says he's used on both 4.4L L322 and his V8
https://www.amazon.co.uk/dp/B00HAH8AU8/ref..._ttl_sol_0
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