hey guys,
got a baffling problem with the coolant temp. So...I changed my heater core in november. Broke my heater control valve in the process and changed that with an MR2 heater control valve. Also swapped turbos to an oil cooled one so the turbo coolant feed and return on the engine are capped. the issue described below only started to happen after i changed the heater core, heater control valve, and turbo.
ever since then my temp gauge acts funny. it heats up (2/3 the gauge) then drops to normal position really fast. after a while it will move to halfway and then drop to normal. This only happens if i drive around. the cycle of the temp needle repeats as described randomly while drive (i.e. under load and not under a lot of load but does not happen when idling). I can let it sit there for ever idling and nothing happens to the gauge other than sitting at normal. temps are in F unless noted. I installed an aftermarket temp gauge and it reads 187 idle, drive around cruising and it goes to 190-199 and sudden drop to 180ish but doesn't stay at 180ish sometimes goes up to 190-197 and drops again to 180ish. drive it hard goes to 220 fairly quick and then after cruising drops down to 197 sometimes 180ish. I have the toyota 88*C stat in it so the idle temp makes sense. the up and down temp sort of makes sense. I am not loosing coolant...weird. i have "burped" the system multiple times. but no change. changed the fan clutch and same thing, changed to a brand new stat from yota and same thing. I suspected the head or a crack. I just did a headgasket leak check with the napa block tester and the test is negative (so no head gasket leaks or cracks in the block or head).
WTF!? the stat acts like there's air in the system. possible not burping the system correctly or well enough? or is the headgasket actually gone and i got a false negative with the napa tester? MLS gasket with arp studs might be causing the napa tester to not read any thing under idle do to lower cylinder pressure vs. higher cylinder pressure under load (so no leaks while idle but leaks under load)?
any help would be appreciated.
got a baffling problem with the coolant temp. So...I changed my heater core in november. Broke my heater control valve in the process and changed that with an MR2 heater control valve. Also swapped turbos to an oil cooled one so the turbo coolant feed and return on the engine are capped. the issue described below only started to happen after i changed the heater core, heater control valve, and turbo.
ever since then my temp gauge acts funny. it heats up (2/3 the gauge) then drops to normal position really fast. after a while it will move to halfway and then drop to normal. This only happens if i drive around. the cycle of the temp needle repeats as described randomly while drive (i.e. under load and not under a lot of load but does not happen when idling). I can let it sit there for ever idling and nothing happens to the gauge other than sitting at normal. temps are in F unless noted. I installed an aftermarket temp gauge and it reads 187 idle, drive around cruising and it goes to 190-199 and sudden drop to 180ish but doesn't stay at 180ish sometimes goes up to 190-197 and drops again to 180ish. drive it hard goes to 220 fairly quick and then after cruising drops down to 197 sometimes 180ish. I have the toyota 88*C stat in it so the idle temp makes sense. the up and down temp sort of makes sense. I am not loosing coolant...weird. i have "burped" the system multiple times. but no change. changed the fan clutch and same thing, changed to a brand new stat from yota and same thing. I suspected the head or a crack. I just did a headgasket leak check with the napa block tester and the test is negative (so no head gasket leaks or cracks in the block or head).
WTF!? the stat acts like there's air in the system. possible not burping the system correctly or well enough? or is the headgasket actually gone and i got a false negative with the napa tester? MLS gasket with arp studs might be causing the napa tester to not read any thing under idle do to lower cylinder pressure vs. higher cylinder pressure under load (so no leaks while idle but leaks under load)?
any help would be appreciated.
