99 GSR integra with B18C. Car started to over heat some what a few weeks back. Assumed it was low, filled it up and went on. Yesterday, the car started to over heat on the highway, managed to limp 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 kick 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. Thanks

 

is the new thermo from honda or what?
did you test it before installing?
if not pull and test. if it's ok then
verify head gasket failure before digging in.

https://www.civicforums.com/forums/7...ad-gasket.html

 

Ill pull the thermostat after work today. Is if normal for them to open randomly? It appears to open at idle, the lower hose gets rather warm. After a short drive, the hose is now cool, not cold, but more like room temp water warm.

 

Pulled thermostat and boiled, actually boiled all three. All three are opening at their rated temps. Is there a way to tell if the waterpump isnt pumping?

 

Anyone know if an engine coolant temp sensor can cause a no start? Havent touched the car since Monday, went to mess with it last night, and itll crank but no start. Havent had time to diagnose, just curious if that sensor would cause a no start.

 

I'd check the timing belt side of the engine for coolant leaks. The timing belt and water pump are recommended for replacement every 90k miles. The water pump has a "weep hole" that will drip coolant, basically to tell you the pump has failed, or is failing. I'd start with the coolant temp sensor, since it's cheap and very easy to replace. My integra is pushing 300,000 miles, and I've done the water pump twice in the last 100k. The last time I used a "Gates racing" water pump and belt, since my economy water pump failed after only 50k. If your hoses aren't hot it's likely the thermostat, but could be affected by the temp sensor.

 

Only issue is, its not actually loosing coolant, did replace the coolant temp sensor, but car currently wont start. I believe its ignition coil. It has spark, but its very weak.

 

No start has been fixed

Now on to the car. Jacked up the front, let it bleed for a while, let the fans cycle 4 times. Car bled fine. Compression tested the engine, 175-180 across all four cylinders. Car does not overheat at idle, only under load while driving. Can rev the car all day at idle, temp needle never moves. Fan still cycles if needle does move.

Now, I do have full water in there now. Mostly tap water. I do not plan on leaving that in there, but COULD all water cause an overheat?

 

Solved, head gasket was leaking gases into the coolant. Had the coolant tested and sure enough, combustion gases present. Swapped out the gasket yesterday, and shes all good now.