I'm aware of the issues with heater pumps, but understand them to usually manifest as a heater that suddenly doesn't produce hot air. My heater gets warm, but not really as hot as I'd expect - is this 'normal', or is there something I can do about it?!

Ta for any input Fingers crossed, I'll be able to spend a bit of time on the car at the weekend - I've got plenty lined up to do!

 

Many complaints over the years regarding weak-ish X300 heaters, including from me. Poor design? or a fault shared by many cars? I dunno.

In full Auto mode the system wants to warm us very gently, it seems. When I want a real blast of heat I manually adjust the settings....sorta "browbeat" the system to give me toasty air.

Let's hear what othes have to say

Cheers
DD

 

Interesting - that's about the same as mine Doug, I've not tried very hard to see how hot it can get though, as it's not got that cold here yet!

My previous daily-driver had a dealer-fit aircon system, which made for vague air conditioning and a far-poorer-than-standard heater. I'd like to get back to being warm in the winter if that's not too much to ask!

 

I crank the temp to max heat and manually go to a higher fan speed to get my toes warm....then *gradually* reduce the temp setting. Once the chill is gone I revert to "auto" setting and all's well after that.

I've had many cars with auto climate control. To be honest only one (Ser III XJ6) behaved as I would prefer/expect. In all other cases I've found the systems to be less responsive than I'd like when heat is called for. The X300s are just particularly lazy, IMHO.



Cheers
DD

 

You're probably right - as long as I can get a decent amount of heat out of it somehow, that'll do! To be honest, I never had a problem with manual controls, but 'progress' is inevitable...

While we're on the subject, whenever the HVAC is turned on it produces a buzzing noise, seemingly from the area of the far right air vent. Anything you've seen before?

 

Aspirator fan, perhaps? On LHD drive cars it's located on the left under-dash panel. I'm *assuming* the opposite on a RHD car....mounted in the right side under-dash panel.

They're known to buzz. Remove, clean, add a tiny drop of light machine oil to the shaft. Oddly, mine would buzz *only* when turning right.

Cheers
DD

 

I'll add that to the ever growing to-do list!
The noise is more like the sort of thing you'd expect from interference through a speaker than something that oil could fix, but it sounds like you're on the right track if such an assembly is to be found in that area.

Cheers

 

Ziggy, make sure your thermostat is not stuck open. That would explain "warm but not hot" for certain ambients.....

 

My heater would only get warm, noticed the temp gauge did not move so replaced thermostat now nice and toasty within about 5 mins.

 

Worth considering! Having had a fiddle on the way home last night, it does get hot, just not quite as hot as I'd like. The temp gauge behaves as I'd expect, but a new thermostat couldn't hurt anyway - these things don't last forever!

It seems that the dial for the temperature of the centre vents doesn't do a great deal - the air temp is as for the other vents, whatever position the dial's in. Unless that's likely to be a simple fix though, I really don't care very much!

 

That's fine, but if the temp gauges reaches "N" that's as good as it get with respect to the heater.

The thermo stuck "open" on my car years ago....on a small road trip in the dead of winter. Talk about cold toes ! :-)






That's just a "trim" adjustment. By design it's a rather subtle thing. Yours is probably OK.

Cheers
DD

 

It sits just below N - I'd assumed that was about normal... certainly behaves as you'd expect WRT time taken to get there & not moving once it's there.

I hadn't realised that about the centre vent, obviously! I've previously had cars with a similar arrangement that allows cold air on your face & warm on your feet... Nice to know it's probably as it should be - I don't like putting up with things not being right, even if they make no difference to me.

Perhaps if I eventually get the to-do list whittled down, I'll add a retro-fit of some heated seats... Mind you, I really should get round to doing some work on my other car if I ever get the chance!

 

Does a thermostat replacement require a gasket, o-ring, or both?

 

I didn't replace the gasket on mine as it was still perfect when i removed it.

Did not see an O ring although one came in the box.

The previous stat was a wax type which had stuck.

 

It requires whatever was there when you pulled it apart....even so an o-ring comes in the box, not a gasket. The housing breaks very easily, btw...even though you are forewarned.....STILL breaks easily...

 

Hmmm... despite my efforts to convince myself otherwise, it's definitely not right - I shouldn't still be chilly after a half hour drive with the heater on as hot as it goes!
I'll order a new thermostat, but I'm still suspicious that there's something not quite right about the heater pump/valve.

 

The pumps are known to fail.

Some guys have luck with DIY brush replacement....that's always seems to be the fault, worn brushes...sourced from a hobby store

Others remove the pump and/or valve and toss it over the hedge, re-routing the hoses in a conventional manner. I can't remember the details on that, but I know it's been done.

If your temp gauge shows "N" that's as good as it gets with respect to the heater. I don't see the point of replacing the thermo.

Cheers
DD

 

Doug,
I'm not expecting the thermostat change to fix it, but having seen the state of most other maintenance parts on the car, I'm going to change it anyway! Likewise with my temperature sender / cold start issue - the evidence suggests it won't help, but with cheap parts that are prone to failure, I'd rather do it anyway.

I'll have a look at whether the pump is running, but I'm fairly sure I'll be able to swap the brushes if that's likely to be all that's wrong with it - I've got plenty of those spare from when I used to have time for such frivolities as RC cars!

 

So, the pump works fine (tested it off the car as well as confirming it 'buzzes' when it should) and I do get hot air - just not much of it!

Temp to Hi, AC off, auto off, vents to face. With the fan set to anything up to 4, the air is hot. Above that, it gets progressively cooler.

Heater valve doing something weird? Matrix blocked? Airlock? Thoughts on a postcard...!

Edit: I've changed the thermostat btw!

 

I sounds like your heater core is partially plugged.