High Idle on 85 CRX When Engine is cold

Hello everyone,

I have a 1985 Honda CRX SI. The car is running great (Just turned
340,000 miles on odometer today!!), however I am experiencing a strange
issue. When the engine is cold, the car will idle at about 2500 RPM.
Once the engine has heated up, the idle goes back to normal. I have not
noticed anything degradation in power or acceleration.

I spoke with a trusted mechanic and he told me he thought it might be
related to a sensor, but he didn't have the equipment to diagnose it
for foreign cars. Has anyone here seen or experienced this issue
before?

Thanks

 

Sounds a bit high for a "warming up" RPM.

As a start, check the level in the reservoir with the car warmed up. Should
be at about the max line. Then, after the car has sat all night and is
COMPLETELY cool, make sure the coolant level is topped off underneath the
radiator cap.

Next, do a purge of air of the cooling system. Use the manual. These are
free online at www.autozone.com . May take a half hour or more for the fan
to come on during this procedure.

 

Hmm, that could be it.... I have a slight crack in my radiator, right
at the top where you fill the reservoir. I loose a bit of coolant out
of that everytime I fill it up. I did top it off the other day and if I
remember right, the next day it didn't idle high. I will try refilling
it again and see if it has the same effect.