I’ve got problems with heating. All the system seems to be operating correctly and I’ve got “warm” pipes going into and out of the heater matrix, but the output from the vents is rarely better than luke-warm.
I noticed yesterday that even on a good run (40+ minutes at speeds between 20mph and 80mph) the temperature guage never indicated much over 60c.
This morning I started the car and let it idle. The upper radiator hose coming from the thermostat housing seemed to start warming slowly almost immediately so I jumped to the conclusion of a faulty thermostat and ordered a new one straight away.
A bit later, I got a break from my desk and so decided to test whether I was going to have problems removing the housing bolts and the housing itself. They came straight out (thank goodness) and so I took out the thermostat. It looks OK. It fully opened at about the right temperature and when cool appears to be closed. I can, however, see a very small gap and a glimmer of light through the top when the valve should be fully closed.
It really is the faintest of gaps, would this be enought to mean that the engine hardly ever gets up to temperature or could be some other reason for that? I used an IR thermometer to check it wasn’t the gauge itself under-reading but it seems about right.
I can’t see any topics on the forums which highlight other potential issues so interested in your feedback.
Mark
1982 XJ6 4.2 Series 3