Yoshiod9

hey guys, i've tried searching already (i'm a big lurker here) but i'm trying to figure out what could cause my y7's water temp gauge to fluctuate from normal operating temp to almost in the red (hot) whenever i sit at a stop light for 30-60 seconds and then accelerate nominally. i've got a 96-00 civic ex header(dc 4-2-1), aftermarket high flow cat(street legal one from http://www.landspeedracing.com), apexi ws exhaust, and an aem cai/short ram. the engine has full oil and radiator fluid...what else should i have checked to find why it is so hot? my cel did come on today but i won't have access to a obdII scanner till i make my way home tomorrow.

would the reason my car is running hot be synonomous with the cel? (kinda obvious question, but i had to make sure). anyway, if anyone has any ideas as to why the engine/gauge is running hot, prior to my figuring out my cel tomorrow, please, lmk. :D
thanks for any help.
-danny

mtetro99

is your radiator fan coming on?

huntarrr

bad thermostat

mp5o

How well does your exhaust setup fit? Any welding/cutting involved? I'm trying to do a similar setup and was just wondering.... Sorry for being OT.

Yoshiod9

mtetro- lol. i honestly didn't even think to check if the rad. fan is coming on. it's late and my car is about 1/10 mile away so i'm not walking out to the garage to see what's up. tomorrow, though, i will.

vsm- how often have you heard of thermostats going bad? especially in a semi-late model car...

hopefully i'll figure out that the cel and the engine running hot is all interrelated.

mp5o- the setup fits well...with the exception of the doughnut gasket between the down pipe of the header and the high flow cat. the cat's piping diameter is too large and i could barely find a gasket to fit between the header and the cat. i had to just sandwhich the gasket between the cat and header by just wrenching the two as tight together as possible. the only thing i got welded was an extra hanger for the mid pipe(the ex exhaust has two hangers and really needs one for the ws system, as it hangs really low) of the exhaust.

Yoshiod9

ok...news update. the cel was for p0420: catalyst system efficiency below threshold. the radiator fan wasn't turning on either. so those probably aren't inter-related incidents...or are they??

i figure i'll just buy a new catalytic converter but what do i do about the fan not turning on? i checked the fuse and that was alright. i checked the wiring harness to the fan motor and unplugged it and plugged it back in but to no avail.

anyone have any ideas on what to do? thanks in advance!

mtetro99

try checking the relay for the fan, switch the one for the a/c and see if it comes on