Coolant consumption when hot

[windymiller]

Have 94 Samurai sj413 with Asian carb, 60K miles, problem with coolant consumption ,approx 1 litre 3 hours increase condensation level in exhaust emission Tried couple of bottles of "Steel Seal" in clean water system fill
Starts on button, Clean fuel. no misfire when hot . No condensation on initial startup, normal condensation after 10 secs from exhaust tail pipe, normal condensation when thermostat opens and coolant circulation through rad. but when temp gauge registers (needle at 7 o' clock) steam emission more evident, extreme when engine revved (increase vacuum) emission dissipates quickly , no oil burn, check with clean rag at tail pipe, no residue on rag just damp
Suspect head gasket --Cylinder head removed : head gasket fire rings intact, slight over heat discolouration on gasket but not blown, head bolts may have stretched on cyl 4, came out easier than rest, Cylinder head sent away for skim and pressure checked "passed" , Valves seating, no brown discolouration on valves. Cylinder head has bypass exhaust recirculation gallery on rear cylinder which was choked with soot, gallery runs across to inlet manifold - cleaned out the port before intake/ exhaust manifold reassembly
No evidence of discoloration of spark plugs, cylinder head exhaust ports/ inlet ports , piston carbon deposits -no marking on cylinder walls
Checked surface of block with level plate / feeler gauge -no distortion
Compression 195-200psi on all 4 cyl, cold ,no significant change when hot, no oil consumption, no water in oil, no oil in water
Coolant system pressure checked when hot no overheat or coolant loss through overflo bottle,thermostat removed , no increase or decrease in coolant pressure when engine running , turned engine over by hand ,incase of crack/ pin hole below cylinder compression rings no change in coolant pressure
Asian Carb has coolant circulation for auto choke , coolant pipes to carb disconnected and plugged to remove possible coolant leak into carb venturi
Coolant at exhaust tail pipe problem still evident!!
is there a possible leak on intake manifold ? no discolouration or wash down of inlet ports , Manifold gasket replaced, is there a EGR valve on engine intake manifold with coolant gallery connection could no see one!
Any ideas before intake manifold or engine replacement?

[ScottieJ]

Well looks like you have checked nearly everything.

If it was a cracked inlet manifold or leaking manifold gasket this would normally show with a misfire and wet/washed sparkplugs so I'd say we can probably rule that out. As far as I'm aware only SPI engines had an EGR valve on the inlet so no issue there either.

I'm a bit stumped if I'm honest, deffo no sign of coolant leaks anywhere?