Hello everyone,

I have an issue with my s-type v8 4.0 Jaguar concerning the heating. Maybe someone here with more experience than me might have an idea what it is.

I did a few tests with different settings on the console and here is what i found.

When A/C is turned on, no matter which setting, from low to hi, the air coming out will be cold. So cold air is no problem.

With A/C turned off, the air coming out is always warm, but only lukewarm. The heating performance is very weak and seems to be independent on if i set it to hi or low.
When driving the car, the heating performance is even weaker it seems. Standing still while the motor is running the heating performance is a little better but weak still as mentioned above.



Could this be the heater valve?

But if it was the heater valve, then wouldn't the air coming out be always cold or always very warm, rather than lukewarm as it is now, especially when driving?

Also, why would the A/C when on always produce cold air? Shouldn't if i set it to HI or 29°C the A/C simply stop, given the heater valve is damaged?


This s-type also has an extra electric water pump for the heater. I thought that this one could be damaged as well, explaining why lukewarm air is coming out still, but again, it does not seem to explain why with the A/C on i always get cold air, no matter the temperature setting.

Unfortunately i don't know much about those matters, so maybe my reasoning is flawed.
Hopefully someone can shine some light on this!

 

Duplicate post.

 

I'd read previous posts and follow what people did. Search on DCCV, for example.