1.9 JDM engine over/underheating
i am after a bit of help if possible..... i have a 1.9 JDM unit in a car of mine, currently i am having chronic issues with over/under heating!!!
About 4 months ago the head was replaced, an injector seal was damaged and couldn't be repaired. Second hand head was sourced, skimmed and a 2 notch head gasket fitted along with new head bolts, cam belt, water pump and inlet manifold.
Recently it has started to blow water out of the header tank, over 2 days it will empty the header tank, so its quite excessive. It only does it under pressure, the header tank and cap are in good condition.
Connecting an obd reader i have managed to get real figures out of the ecu whilst driving.
Ambient temp was 9 degrees, car took ages to warm up, when it finally warmed the temp fluctuated between 72-85 degrees, and this was fast A roads.
Turned the heater on full blast at 28degrees and the temp dropped from 82 to 78 degrees very quickly.
Pottering around town at about 30mph the temp sat at 84 degrees, out on the motorway at 80 mph the temp dropped to 78 degrees.
Ran for 5 miles up the motorway temp dropped to 70 and then back up to 82, by the time I came off the slip road it was down to 75.
Pulled over and held the car on a fast idle (2000 rpm) for 5 mins, temp never moved from 80degrees
first thought was thermostat, removed it and tested it, opens perfectly, radiator flows water with no apparent blockage put it back on the car, refilled the water and ran it up to temp.
Again couldn't get it to rise above 86degrees, but this time I notice the rad was stone cold, the pipes rock hard and when I opened the drain plug on the rad the water was cold, but the engine was sat at 86 degrees!!!
with the hoses off and the engine running there is a flow of water out of the engine, so that would point to the water pump working.
the radiator fans never kick in, i dont think i have ever heard them, the temp gauge never moves from the middle of the gauge although my obd reader tells me otherwise.