StayKrafty

Posted over in the Teg forums, but those seem to get less love these days. So lets assume this, 95 Civic Si, with a JDM B18C, P28 ECU, tuned on netptune. Car started to show some signs of the needle moving towards hot, topped off coolant, has been fine since. Now it started to overheat bad, turning heat on didnt help, so limped it home.

What has been changed:
Thermostat x2
Rad cap
Radiator
Hoses
Flushed
bled numerous times

Now, car will bleed while at idle just fine. Thermostat opens, fans cycle. Normal temp achieved. Drive the car for maybe half a mile, temp starts to climb again. Pull over, top hose is hot, bottom hose is some what cool. Much like the thermostat never opened back up once I put the rad cap back on. Hoses are pressurized, coolant flows to over flow (granted, a few times it was so full it was spewing out) but doesnt appear to return to the radiator. Heat is and has been hot. I cant imagine I would still have air, unless the head gasket is gone and its pressurizing the rad. Car runs and drives normal, no smoke, no oil in coolant, no coolant in oil. Just looking for some other suggestions before I go the route of changing the head gasket. Also, coolant smells of coolant, no gas smell from it.

That this was written Monday when I last touched the car. My current question is, can the engine coolant temp sensor cause a no start? Messed with the car last night and couldnt get it to start. It would crank, but not fire. I get off rather late at night, so didnt have time to see if it was getting spark. Keep in mind, car would start and run fine Monday, but now its not. What should the coolant temp sensor read for ohms when cold? tried testing and from what I could gather read OPEN, but some times would read 1.8k ish, but most of the testing read OPEN. Cant test when warm if I cant get the car to start. Going to be checking more into it when I get off work tonight, just looking for options.

StayKrafty

Bumpity bump

civicservice

Given you've had issues with abnormally high engine temperatures and those incidents with the reservoir overflowing, a problem with the block might be the cause.

Before replacing anything, though, you might want to do a leakdown test - or at least a compression test. Poor compression could be why the engine doesn't start.