EB II i6 4L Sudden Temp Fluctuation
I’ve got an EB II i6 4L, rebuilt a good few thousand k’s ago. When it was rebuilt the radiator was changed with a new one; not reco, new, I brought it myself. The cars also had a thermo fan conversion for over a year now. About 2 weeks ago I started having issues with the heater cutting out and temp rising while sitting at lights on my way home from the city. The fans would cut in, but it was not until I would start driving that hot air would start to come out of the vents gain, and no it wasn’t a vacuum issue. I replaced the thermostat and the heater issue stoped, but instead the car started to get much hotter before the thermostat would open and drop in temp. As an example I have the high series dash in my car, and normally the car would sit on the ‘N’ in relation to the word ‘Normal’ written within the gauges normal operating range, and get about half way up before opening the thermostat, but it started to sit a little higher and would get all the way up to the ‘L’ now before you would suddenly see it drop. I decided to replace the thermostat again with a different brand. The one I now have also has a predrilled hole in it with a small valve that appears to allow some coolant flow while the thermostat is shut. This one however is no better than the last. On top of doing opening late and running much hotter, now about half way, it is also fluctuating while I drive, even at 100kmh along the freeway it will still be going up and down in temp. Anyone with some past experience able to shed some light on this issue? I went through the cooling system air purge procedure last night but today on the way to work it was still doing the same thing.
Another note, after reading a few posts on the forums, no, I don’t believe the performance has dropped off either. Fluid level and oil levels are fine, using coolant with correct mix for the engine, and running high quality oil, same stuff I’ve been using since the rebuild, changed at regular intervals. I have not fully investigated the issue yet, but I’m after anyone’s experiences with this so I have something to go by when I have a look again tonight.
Thanks in advance,