My son's 2010 Civic DX-VP has a major issue with overheating during a long drive or anytime it is going faster than about 60. Runs about 2/3 to 3/4 of gauge normally, but tops out when under any load. Must implement mass heater-blow to cool down.

• Originally, we discovered a seam leak on the radiator and replaced it and both hoses.
• The fan blade had also disintegrated and we replaced the unit. Still overheated.
• Replaced the thermostat and the lower ECT.
• Replaced the ECM and had it reprogrammed/updated by Honda dealer.

• All relays are good
• Fans run appropriately
• No water in oil
• No condensation under filler cap
• Coolant pressure test -extremely slow leak down-about one drop/2 or 3 minutes, external to engine
• Runs well
• Compression check

#1 188

#2 184

#3 180

#4 190

 

Let's start simple, has the rad cap/coolant reservoir cap (whichever one you have) been tested/replaced?

 

Yes it has.

 

Replaced water pump. Old one was fine. Next stop, head gasket.

 

So, I replaced the head gasket and got everything all buttoned up again. Engine started right up. Topped off fluids. Turned off engine. Checked tire pressures.

The "D" for Drive was blinking and the service engine light was on. Not knowing what the blinking D was all about, I read the codes and cleared them. I expected codes, due to all the disconnecting and reconnecting, so I didn't really pay much attention to them. One was the camshaft position sensor, and the other may have been the some, or maybe crankshaft sensor. Anyway, now the engine won't start at all. It cranks for a while and then one little putt and then cranks some more. D still blinks.

Any ideas??

 

Well, that little interruption has been solved. Found the camshaft position sensor disconnected. Plugged it in and the blinking went away, engine purrs, and car still runs hot. Not a warped head, because I just installed a fresh resurfaced pressure tested head.
Just put in a 170 thermostat to see if it makes any difference. Maybe the old one went bad?

 

Well did the Thermostat work? issue gone?

 

No, made no difference. Finally threw in the towel and sold it to someone who was willing to take a shot at it.